In the past, hardware calibration feature was limited to premium wide-gamut models from companies like NEC or Eizo. Those models offer wide gamut, great uniformity and advanced calibration features…but at a fairly high price. Affordable wide gamut solutions with hardware calibration started in 2013 with Dell and after that other companies like LG, BenQ and Samsung begun to offer “similar” products with more or less success. It is important to point out that LG and Samsung wide gamut models cannot be properly calibrated internally with the i1Display Pro colorimeter using their software and the same applies to some BenQ models like SW2700PT and its Palette Master Elements software. The main issue with those models is that they bundle an outdated X-Rite SDK (Software Development Kit) in their software without GB-LED support, which is the current main* (see the footnote at the end of the article below) LED wide gamut backlight technology. Hence, their software won’t get the same accurate readings as with the proper correction, which in turn leads to less accurate calibration than it should. The BenQ PG2401PT and its Palette Master software, on the other hand, come with proper GB-LED support.
Updated on 06/06/2018: X-Rite / Dell released a new version of DUCCS software 1.6.5 – please see the notes below. All current Dell Wide Gamut monitor owners are highly encouraged to update and recalibrate their screens to get better accuracy.
These low-budget wide gamut monitors were an interesting option for hobbyists and professionals, who cannot or do not want to spend more than $1,500 on a fully-featured premium wide gamut monitor from NEC or Eizo. The release of Eizo CS240 in late 2014 lowered that budget gap, since it is a near fully-featured wide gamut monitor for $850-900 USD and was one of the most sensible and affordable choices.
Since 2013 Dell has released several GB-LED models with hardware calibration. Here is a brief overview of their features:
- sRGB, AdobeRGB and for new models DCI-P3 factory gamut emulation, also called factory calibration. Factory calibration is done at default brightness and contrast OSD values, 50%, which means a high cd/m2 output. Factory calibration white point is not accurate at all but gamut, gray balance and TRC is more or less accurate. You will need graphics card calibration on most units to make use of them (white point correction). You cannot fix factory calibration “inside” your monitor.
- 10-bit / channel input to monitor, for compatible hardware and software.
- “Custom Color” OSD mode with full native gamut, and fully customizable values for RGB gain and offset controls, to help with graphics card LUT calibration.
- Two OSD modes serve as independent “memory slots” for user’s hardware calibration, CAL1 and CAL2.
- Uniformity compensation feature, with limited usability and not available at all for some OSD modes.
And below are their issues:
- 2013 Models: U2413, U3713H, U3014. These were 1st generation of Dell’s GB-LED monitors with AH-IPS panel. They have more or less “good enough” uniformity but serious overshoot (ghosting) issues. In order to get faster response times and advertise magic “8ms” number, a strong pixel response policy is applied to electronics. This kind of strong and fast change when changing a pixel value from dark grey (let’s say 80/256) to a lighter grey (let’s say 160/256) made that pixel bright with a much more lighter grey during a short time interval (let’s say 200/256 as an example), which caused overshoot ghosting. For example, while scrolling text in an internet browser, ghost images of moving letters appear as you scroll up or down. A uniformity compensation feature was advertised but cannot be enabled in hardware calibration OSD modes CAL1/CAL2, and if enabled in other OSD modes, it will block OSD brightness and contrast controls at 50%: this means a very high cd/m2 output not suitable for some applications. 1st generation was bundled with the very first version of Dell Color Solution software (DUCCS v1.0.x), a customized Color Munki Display software, which was buggy and inaccurate. v1.0.x versions work only with Windows and i1Display Pro colorimeter. To use exclusively i1Display Pro was not a real limitation, since it’s the only good and affordable colorimeter which has X-rite support for hardware calibration.
- 2014 Models (4K GBLED): UP2414Q and UP3214QThese were the very first 4K IZGO GBLED models available to public. Being the first out, there were some issues and limitations. Bad backlight brightness control was applied to the 32″ model: slow under 1KHz Pulse Width Modulation (PWM) was used for this task which may be a problem to some users, leading to visual fatigue. Also, they use DisplayPort and MST for 4K resolution at 60Hz, but MST makes some OSes think that there are two monitors with half the resolution attached to the DisplayPort output of a graphics card. With these 2014 models Dell released a new DUCCS version, 1.5.x, which is now i1Profiler customized software. More accurate than the infamous v1.0.x version, with more profiling options. This new DUCCS version is available too for the 2013 models like U2713H, which is obviously good news for their owners. Now DUCCS supports i1Pro2 spectrophotometer (and i1Pro is reported to work too) but keep in mind that these devices are less accurate than i1Display Pro colorimeter for a GB-LED display. Also, the first OSX versions of DUCCS were released but it seems that they only worked with 4K models – they won’t write LUT data to CAL1/CAL2 in 2013 models.
- 2015 (5K GBLED model): UP2715K. 1st GBLED 5K available to public, there are issues related to bad color uniformity in a significant number of units. New DUCCS version released to support this monitor, which turned out to be very buggy. A new OSX version was released too.
- 2016: UP2516D, UP2716D, UP3216Q. It is a refresh of the previous GBLED generation with a backlight (a little different, in red wavelengths). This is not really a problem since i1Display Pro filters are almost equal to CIE 1931 2º in those wavelengths. At this point of time there is not an EDR from X-Rite with that specific backlight… maybe because i1Display Pro is well behaved in those wavelengths, so we are going to call them “GB-LED” in order to not to confuse our readers. Dell users have reported very bad quality control, uniformity issues everywhere and uniformity issues beyond 6 deltaC (Spanish Canon DSLR forums) which are unacceptable values. Dell released DUCCS v1.5.10 to support these new displays but it offers less functionality than v1.5.3. Some of these new units need a firmware update to work with v1.5.10. Hardware calibration for 32″ 4K model seemed to be broken since DUCCS was unable to upload an accurate LUT (banding issues, grey coloration artifacts…) at least for some units. Dell also modified uniformity compensation feature, but it still cannot be enabled in CAL1/CAL2 OSD modes. If this feature is enabled in “Custom Color” OSD mode, it will block RGB gain control, so the user is unable to change the white point inside the monitor. Despite this, now users can use brightness or contrast control to lower or raise cd/m2 output even when uniformity compensation is enabled. If the native white point is close enough to your desired white point, you can see it as an improvement, but users will need GPU LUT calibration to fix white point, grey and TRC.
This is the sad tale of affordable wide gamut monitors, a promise that could be, but wasn’t. Some of them truly offer value for their price and still can be purchased today if they are sold for a fair price: U2413, U2713H or UP2414Q…and even UP2516D / UP2716D but it’s highly recommended to check color uniformity (ArgyllCMS/DisplayCAL).
When looking at its competitors in its price range, the sad tale becomes a tragedy:
- LG: very serious uniformity issues, reported to be >4deltaC (unacceptable), in its two 27″ QHD and 31″ DCI-4K wide gamut models. Software unable to make i1Display Pro measure a GB-LED properly (and that colorimeter is the only real choice). The reason is SDK issue discussed earlier.
- Samsung: unable to make i1Display Pro measure a GB-LED properly (same SDK issue and Spyder won’t measure it properly like with other GB-LEDs) and pretty low contrast after uniformity compensation is enabled. That means about 600:1 contrast at daylight 6500K (D65) white for such an expensive monitor, almost unsuitable for video or even sRGB content…since a “good enough” sRGB 24″ monitor has more than 1000:1 contrast for much less. It’s a bad deal unless it is used just for soft-proofing purposes. Low contrast means “more glow” on IPS displays, so you will need to sit further from the monitor to lower this effect. NEC or Eizo’s 32″ 4K models can get superb uniformity without sacrificing too much contrast but they are a lot more expensive.
- BenQ: has an overpriced PG2410PT model that is unable to offer the same features as NEC/Eizo counterparts in its price range. The software for this model, Palette Master, is like DUCCS, a customized i1Profiler and comes with proper GB-LED support. They have another model, SW2700PT, with bad quality control and uniformity issues like 2016 models from Dell and its software is unable to make i1Display Pro measure a GB-LED properly (same SDK issue, again). New SW271 and SW320 models offer good features, but the same uniformity issues remain.
- HP: has an expensive 27” model with hardware calibration within its firmware, without a computer. The sad tale is that built-in calibration is not very configurable, just a few presets, and it needs a specific i1Display Pro OEM version from HP which is a ridiculous requirement. HP offers an SDK for calibration under Windows, Linux or OSX, but AFAIK there is no user-friendly software that can calibrate them with a retail i1Display Pro. If you have very good programming skills it could be interesting to bring ArgyllCMS features to that HP internal calibration. This monitor is not bad, but it’s too expensive for what it offers and lacks user-friendly software. HP also offers a 32” 4K wide gamut with hardware calibration and proper GB-LED support for i1Display Pro (it comes with de-updated SDK and GBLED EDR).
Given these facts, I would stay away from any of these Dell models with high prices since they are not worth it: the risk of bad uniformity units is too high for the bigger screens and software for hardware calibration has some issues as we will see in this article. I would stay further away from LG or BenQ models since their cheap models have worse uniformity issues than Dells (at least worse than 2013 models) and their software is unable to measure them properly with a colorimeter. Crippled contrast after you enable uniformity compensation in Samsung’s 32” 4K wide gamut is not appealing for such an expensive monitor…you can get a fully featured 27” QHD wide gamut from NEC for that price and NEC offers 5-step uniformity compensation trade-off between max contrast and max uniformity.
This does not mean there is no hope for hobbyists or professionals with limited budgets. As I have pointed out before, models like U2413, U2713H or UP2414Q seem to be a sensible choice… but only if found for a fair (I mean low) price for their value, since they are pretty old models. Customers need to be aware of these Dell limitations before buying. This is the point of this article: to learn, evaluate and if possible fix their flaws.
Eizo CS240 (24” 1920×1200, like U2413) had an affordable price too and it’s very likely that it will show better color uniformity than Dell. It offers true uniformity compensation feature but it’s only an ON/OFF feature, there is no tradeoff for contrast-uniformity. Its price is about the price of a 27” QHD GB-LED Dell like UP2716D, so this Eizo is another sensible choice for limited budgets.
For better uniformity or more calibration and color space emulation features, save money for middle-high (Multisync PA) or high end (Spectraview PA) GB-LED models from NEC since they are cheaper than Eizo counterparts. NEC’s Spectraview PAs offer the same quality as ColorEdge CG Eizos and the cheaper Multisync PA models offer better features than Eizo CX series.
Dell Color Calibration Solution (DUCCS)
After GB-LED family presentation, let’s see what these Dell owners can get out of their monitors and DUCCS software. Since v1.0.x versions were useless, this is a guide to the 1.5.x and 1.6.x family:
-1.5.3 which works with 2014 generation or older models. This is the recommended version for that monitors unless you notice bugs.
-1.6.5 is the latest version that is needed for the most current Dell monitor models.
Quick notes on the latest 1.6.5 release:
- You can choose (constant) gammas other that 2.2 and sRGB. Previous versions when user selected a different gamma than those two, it reverted to 2.2 gamma in calibration process. L* and custom target TRC are still missing although we suggested X-rite that this would be a nice feature
- You can choose “Native gamut” as preset and at the same time configure a custom white point and gamma. Very nice feature, very useful for printing purposes.
LUT-Matrix-LUT inspection from log files and USB communication showed true native gamut with an emulation matrix equal to identity matrix (no gamut emulation). You can forget the tricks we explained in previous versions article to get native gamut xy coordinates for RGB primaries. Easier for you, good!
- The number of calibration patches increased from 11 to 24 per black to R+G+B+W native gamma ramp. This allows DCCS to capture color oscillations in uncalibrated grey ramp in a more accurate way. One of the flaws of previous versions is that some Dell monitors come with a bad grey neutrality out of the box (Standard, Custom color, CALx… all but sRGB / AdobeRGB and such presets). If you take too few measurements of native uncalibrated gamma ramp… you cannot expect to correct such bad behavior because these issues may not exist at all in those few patches measured. Now with 24 patches a calibrated troublesome U2713H showed grey range a*b* going from 1.8-2.2 to 1.4 or lower against a true neutral grey reference (not a profile reference which would be easier to attain). Good work!
The “grey range a*b*” is a measure of color oscillations across grey ramp, such as if you have one grey with a small pink pint and another one with a slight green tint (tinting going in very different “color directions”). The worse these tints are, the higher gray range will be. You can obtain this value with a profile verification in DisplayCAL or you can see this concept as “range” value in monitor reviews of prad.de.
- White point accuracy against desired target gets a good but not perfect accuracy. Brightness OSD control is modified after DUCCS wrote LUT contents into the monitor, and in some GB-LED models white point drifts a little when you mess around with brightness OSD control. It’s about 2dE from desired target at D65 (white point after DUCCS was between daylight and black body curves ~2dE from each one, in the middle) … but it was very accurate with “printing environment” white points like D50, more accurate than any other previous version. DisplayCAL could correct that small drift in GPU LUTs without effort if your graphics card has appropriate hardware (high bit depth LUTs and dithering).
This update seems to work with all DUCCS compatible monitors including old models like U2413, U2713H… etc. on Windows 10. You should update DUCCS to this new version. I’ve seen no USB communication errors or crashes but if you find issues report them to Dell/X-rite.
As a side note, with DUCCS 1.6.5 comes an update to X-rite Services. That update carries a new EDR spectral correction called “Panasonic VVX17P051J00 in Lenovo P70” with a gamut close to but smaller than P3. This spectral correction is not intended to be used with current photo wide gamut monitors. Spectral power distribution (SPD) of this backlight once plotted in a 2D graph is close to SPD from a new “P3 iMac” but its gamut is just a little bit smaller than those iMacs which are almost full P3. It is also smaller (by a huge amount, like iMacs) than the gamut of newer Dell UPs or newer CG Eizos like CG247x, CG2420,
I would like that X-rite include a spectral correction for these new wide gamuts (usually called “W-LED” backlight where W is not like WLED -white led- backlight of sRGB LED displays). They have it, at least one sample called “HP_DreamColor_Z24x_NewPanel”, but they offer it just to HP hardware calibration software. You can import that HP spectral correction manually (go to HP website) if you want to measure an UP2716D with DisplayCAL or make a graphic card LUT calibration with DisplayCAL in these Dell’s “Custom Color” OSD mode… but you cannot use it in i1Profiler or DUCCS (limited to GB-LED, called “RG Phosphor” in X-rite’s naming). X-rite tools available to their customers need an update regarding this subject: more EDRs (spectral corrections) for current backlights.
User interface and almost every option are common to all 1.5.x and 1.6.x versions, so unless stated otherwise this guide works with all of them. The following instructions are for the Windows version of DUCCS, OSX version should behave in a similar way unless bugs or Apple hardware limitations or incompatibilities are found. Ask Apple support team if DUCCS does not work for you…you are on your own since it seems that there is no official support of Dell monitors with Apple proprietary hardware configurations.
DUCCS included on your monitor driver CD may be outdated. They can be downloaded from Dell or Xrite websites. Below are the links to Windows versions (Windows 7 or newer is required):
DUCCS 1.5.3 (don’t worry about the model name on the page, it works with all 2014 and older models):
DUCCS 1.6.5 (the latest version)
Installation will need administration privileges; it will also install i1Display Pro SDK, X-rite Services and .NET Runtime. After installation, which may require a reboot, you may want to check Windows Update for .NET Runtime security updates. Al the end of the process you should have a desktop shortcut to DUCCS. Before running DUCCS, plug in the i1Display Pro colorimeter. Windows may want to install is as a HID device (like a mouse, keyboard…), let it do the job.
The newer 2016 Dell UltraSharp models may need a firmware update (at your own risk).
While newer versions of DUCCS may work with a dual monitor setup, it is strongly recommended that there is only one widegamut LED Dell connected to your computer when running DUCCS (or even one monitor at all). Calibrate each display separately.
Now run DUCCS. If you are running 1.5.3 and have Internet access, it will prompt you to update to 1.6.5. This new version is worth trying for the new features and bug fixes. After it starts you should see DUCCS main screen which looks like X-Rite’s i1Profiler for those familiar with the program:
On the middle of the screen you will see a “User Mode” selection. Go ahead and pick the “Advanced” option so that you can see all the available calibration options.
Next, click “Display -> Profiling” to proceed with internal Calibration. The next screen will show your Dell monitor with its serial number and a set of presets for calibration target. If you do not see this screen and you see the usual i1Profiler calibration target with white point, luminance and contrast, then your monitor is not recognized by DUCCS as a Dell with hardware calibration. Unfortunately, it is a common issue for 2013 Dells under OSX. Here is how the screen should look like:
A brief explanation of the presets:
- sRGB: it will create a LUT-matrix calibration that emulates sRGB gamut, with D65 white and “sRGB gamma”. sRGB gamma is not equal to a 2.2 gamma, it is close to 2.2 but is lower (brighter grey) near black and higher (darker grey) near white.
- AdobeRGB: it will create a LUT-matrix calibration that emulates AdobeRGB gamut, with D65 white and “2.2 gamma”. It will try to get as close as it can to full AdobeRGB gamut.
- “Custom xy”: it will create a LUT-matrix calibration with gamut defined by CIE xy coordinates of R, G and B primaries. “Custom xy” preset has a customizable white point target with a few presets like D50 or D65, custom daylight color temperature and a full custom white under “xy” for CIE xy color coordinates. There is also a “measure” option to match whites but due to DUCCS limitations it is not useful with i1Display Pro when matching another display: you can use an external program to properly measure xy coordinates of whatever white you want to match. There is a combo box for Gamma (TRC) selection. You may choose between a constant value or “sRGB” TRC. There was a bug in versions between 1.5.3 and 1.6.5 that only allowed you to choose between 2.2 and sRGB, now it’s solved. Unfortunately there is no L* gamma preset, or a custom curve defined in a text file although I’ve asked X-rite team for this feature.
- Native: Native gamut with custom white point, gamma. Very useful setup for soft-proofing.
You may have noticed that “sRGB” and “AdobeRGB” presets are just particular configurations of “Custom xy” and it’s true. You only need to know CIE xy color coordinates for R, G and B of sRGB and AdobeRGB (available on Wikipedia for example) in order to manually set an AdobeRGB calibration target without presets.
It is very useful if you want to calibrate to sRGB/Rec709 gamut, D65 white but 2.35 or 2.4 gamma for video purposes: just go to Wikipedia, get xy coordinates and setup your desired white and gamma.
DCCS does not allow custom contrast value, it will aim to the best contrast that fit its needs. If you need a fixed contrast value (paper) you cannot do it with DCCS, you will need GPU LUT calibration and tweak monitor’s brightness and contrast controls under “Custom Color” OSD mode.
After choosing your calibration target, click next. Now you are prompted to choose a profile configuration, the way monitor behavior will be stored in an ICC/ICM file after calibration:
Here is a short explanation of the options:
- Chromatic Adaptation: is about translation of coordinates from your desired gamut and white to a Profile Connection Space (PCS) defined at D50. This PCS is where color management operations are done. There is lot of free information about color math involved, but we are trying to keep this guide simple (no formulas). Bradford or CIECAT02 will work fine.
- ICC profile version: it MUST be version 2. If you choose version 4, you won’t be able to validate profile with ArgyllCMS and some incompatibilities with other programs may happen too. Choose version 2 in this step, always.
- Profile type: Matrix profile will create one of the simplest profile types. If will assume that after calibration your display has a neutral grey, be it true or not, so profile TRC values will be equal for R, G and B channel. Table profile will create a complex profile with a more accurate description of actual after-calibration behavior. It will make 3 independent TRC for each channel. Firefox is a color-managed browser but it will not understand X-Rite’s table profiles, even tweaking its advanced configuration, so you are better off keeping it as Matrix profile if you want to use Firefox.
After choosing profiling options, click next.
Now you are prompted to choose a number of color patches for profiling. These patches are not for calibration, just to profile your monitor. With DUCCS you cannot choose patch set for calibration and this is one of the former main reasons of its inaccuracy. The bigger the patch set, the more information DUCCS can use to compute display’s profile in an accurate way. The simple nature of matrix profiles makes them suitable for a low number of color patches.
Now you must choose where to store calibration: Calibration 1 (CAL1) or Calibration 2 (CAL2):
If this screen does not show up, you are not able to hardware-calibrate your Dell because of some software or hardware issue. If an error shows with information about “no USB cable plugged from monitor to computer”, check it, but maybe monitor’s USB hub drivers are not properly installed, or maybe it’s a DUCCS bug. Sadly, if this happens, you are on your own. You can report this problem to Dell or X-rite.
At this DUCCS step, the software tries to communicate with your monitor in two ways (DDC/CI and USB) to read the serial number. If any of these operations fail, this kind of error happens.
If there are no errors, proceed by clicking “Start Measurement”.
At this point of calibration, DUCCS will go fullscreen and will prompt you to uncover the i1Display Pro lens and place the device on the center of screen. When done, click next.
Now, the actual calibration starts. User has no control during this process so just sit and wait:
- The chosen CAL1 or CAL2 will reset to factory configuration, erasing previous internal LUT data
- It will measure a few white and R, G and B patches and change contrast OSD control for that CAL OSD mode until measurements meet its needs (whatever they are, DUCCS is just a black box, not GNU software). That means that you can get lower contrast (-200) than its nominal 1000:1 value near native white, and even lower contrast for warmer whites which are far from native white point. User has no control over it.
- With contrast configured, it will measure several calibration patches in order to measure uncalibrated monitor response: it will read 24 patches for native gamma for every channel plus grey (24×4). Former versions only took 10-11 per channel and that one of the most severe issues with previous DUCCS. If there is some kind of bad behavior (pink-green tint for example) between those measures (read my first article), DCCS cannot correct that grey because this bad behavior does not exist for DUCCS. It didn’t measure it! Next, it reads several patches for gamut measurement: secondary colors, etc.
- With that information DUCCS will compute actual LUT-matrix data that brings that uncalibrated state to target calibration values with more or less accuracy. A pre-lut (target gamma), matrix (gamut emulation) and post-lut (de-gamma, neutral grey and white point calibration) data for internal LUT are computed, compressed and sent to monitor. White color may change to pink or some weird color during this process. Hardware calibration for the new 32” 4K UP3216Q seems to be broken here with DUCCS 1.5.11, it seemed to be unable to write or to compute an adequate LUT3D for this model. Maybe this hardware has another LUT format, or it is just another DUCCS bugs. We have not tested v1.6.5 with that model.
- After internal LUT is written, DUCCS will try to fix luminance, trying a few brightness OSD values till it gets the closest OSD control value to desired value. There isn’t a fine tune for desired luminance, just a best effort. Since LUT calibration was written, white point may drift a little from desired value if DUCCS changes brightness. This is another source of inaccuracies of DUCCS calibration, improved in v1.6.5. but not totally solved. Some monitors drift more with OSD brightness changes, it could be accurate for you or it could go up to 2dE from desired target.
At this point CAL1 or CAL2 are calibrated to our desired target, but you need an ICC profile too because color managed applications need to now actual monitor behavior to manage color properly. DUCCS starts a series of patch measurements (chosen in profile configuration step) and stores that information in computer’s memory.
After all patch measurements are finished, DUCCS will ask you to place close the i1Display Pro lens. Click next after you are done. Then DUCCS goes back to windowed mode. Click next.
Now you are prompted to choose a profile name. Write a meaningful name like “DELL U2413 sRGB CAL1.icm”, do not overwrite the generic “U2413.icm” profile. Click on “Create and save profile”, which will transform profiling measurements to a profile and write it to an ICM file, stored in your Windows OS profile folder. It will also set it as a “Default Profile” for your Display in the “Color Management” configuration of Windows Control Panel. That means that all color managed applications will work like if that profile accurately describes your monitor, but this won’t be true if you either factory-reset the monitor / reset that CAL1/CAL2 slot or change OSD mode from your CAL1/CAL2 to other mode.
Now you can repeat the process for the other CAL1/CAL2 slot or exit DUCCS since all other application options are not useful: uniformity, validation…not as reliable as DisplayCAL, not so accurate so not to be trusted. We will deal with validation and uniformity measures in next article.
Since calibration is stored inside the monitor, you can take DUCCS’ ICM files with its behavior to another computer or OS (Linux, OSX, another computer with Windows), then install one of those profiles as the default profile for your display. Profiles are stored in “C:\WINDOWS\system32\spool\drivers\color” folder in Windows OS.
You need to know that OSD brightness/contrast values for CAL1 and CAL2 are independent from the other OSD modes, but they may be independent too for each DVI/DP/HDMI input (may vary with model/firmware revision). If you calibrate your Dell monitor on a desktop computer connected with a DVI cable to your monitor and you want to use that calibration with a laptop connected with HDMI to your monitor, then you may need to copy OSD contrast & brightness value from CAL1/CAL2 modes in DVI input to CAL1/CAL2 brightness and contrast controls in HDMI input. CAL1 and CAL2 computed LUT will remain unchanged between monitor inputs, it’s just contrast and brightness values what you may need to copy to the other inputs. The same applies to RGB gain and offset controls for “Custom color” OSD mode (for GPU calibration), each DVI/HDMI/DP input may need its own configuration.
Color Management Configuration for MS Windows
If you go to Windows Control panel, and double click on “Color Management” you can change default profiles for each of your displays. On Windows 10, visit “System”, click “Advanced Display Settings” under “Display”, then click “Display adapter properties” under “Related settings”. When a new window comes up, click on the “Color Management” tab, then “Color Management…” button to see the following screen:
Under the “Devices” tab there is a Device drop-down box. Make sure that your Dell display is selected. Don’t forget to check “Use my settings for this device”. Below that you will find a list of profiles associated to that display. You can add and remove profiles. You must select as “default” profile the profile that matches your current monitor configuration before using color-managed applications. For example, for CAL2 calibrated to AdobeRGB preset in a U2413 with DUCCS, there must be a profile with your desired name, “DELL U2413 AdobeRGB CAL2” ICM file. Make sure that this profile is set to “default” while in CAL2 OSD mode.
Do not change anything in the “Advanced options” tab – leave it as is. The only change that may make sense for some configurations is to enable Windows LUT loader for GPU but it is not recommended. To enable it, click on the bottom button “Change system defaults” (administrator rights are needed). It will open another “Color management” configuration. Go to advanced tab and enable “Use Windows display calibration”. Then close all Color management windows.
With this LUT loader enabled, every time you set as “default” a display profile, Windows will load that profile’s calibration curves in graphics card LUT. DUCCS profiles have a linear LUT (no calibration), so this configuration is not needed, but if you use i1Profiler or ArgyllCMS profiles mixed with DUCCS ones, then it may be useful. Windows LUT loader is less accurate than ArgyllCMS LUT loader. It will load a low-resolution version of calibration curves (without “decimal values” we talk about in my Basics of Monitor Calibration article) which may lead to banding artifacts. This does not matter at all for DUCCS profiles, they have a linear LUT calibration embedded. Unless for some strange reason you do not want to use 3rd party LUT loaders, I would avoid MS Windows LUT loader and use
ArgyllCMS/DisplayCAL. DisplayCAL 3.3.x comes with an autoloader that notices a change in “default profile” (actually it seems to be a polling mechanism) for each display in your OS, and IMHO it’s the way to go.
Keep in mind that if you change the preset mode on the monitor to a different one (say from sRGB to AdobeRGB) and forget to change it in the Color management settings above, then fire up Photoshop, all colors might be wrong. Your display (while in that OSD mode) has a close to AdobeRGB behavior, but Photoshop will do color management as if it was close to sRGB. Before you open a color-managed application, there must be an accurate profile for your current OSD mode set as “default” for your display, as shown above. This is not a Dell limitation, this is true for every monitor and every operating system… unless a color managed application has its own monitor profile configuration. Because of this, always make sure to select the same preset (CAL1 or CAL2) as the default Color Management profile in your settings. If you change one, don’t forget to change the other. It may be possible to do this change sequence automatically with a third-party application like Dell Display Manager (after tweaking it, out of scope of this guide). The same happens with Eizo/NEC monitors and their OSD configuration programs.
*NOTE: X-rite packed a GB-LED backlight SPD sample under “RG_Phosphor” EDR file – it covers AdobeRGB 99% LED backlight models. That GB-LED SPD is not exactly the same LED backlight for iMac 5K DCI-P3 (smaller gamut) or super high-end Eizo CG318-4k (bigger gamut); there is a noticeable difference in red channel output SPD between GB-LED backlight and those two models. ArgyllCMS with SPD sample data from those two displays (a “CCSS” file with SPD data) can properly measure those displays with an i1Display Pro, so do not worry about it.
Validating DUCCS results
As seen on the previous page, DUCCS could make some mistakes or take some assumptions like that monitor has a nearly ideal uncalibrated behavior when measuring and computing LUT calibrations for Dell monitors. This means that your calibration may be not be as good as it should be, which is the reason you might want to validate it. The built-in DUCCS validation feature is not accurate either and it has no means to correct some issues even if its validation was useful.
For much more reliable and accurate validation of calibration results from DUCCS, you will need a third-party application called ArgyllCMS, which is free software under GNU license, available for all major OS platforms including Windows, Linux and OSX. This method of calibration validation using ArgyllCMS is not exclusive to Dell monitors, so you can also use it to validate NEC, Eizo or other monitors. ArgyllCMS is developed by the talented Graeme Gill and while it is completely free, if you like the tool, you can always support its development with PayPal contributions.
ArgyllCMS can calibrate (GPU LUT, in graphics card LUT) and profile your monitor, but also profile printers and scanners or even compute LUT3D data to use with compatible software for video. In order to install it, you only need to download the zipped executable for your platform and decompress it in a folder. No installation is needed. There are only two requirements:
- Profiles must be ICC version 2
- Measurement device must be supported for the software (true for i1Pro / i1Pro with a specific driver and for i1Display Pro / Color Munki Display without drivers).
ArgyllCMS is a set of command line applications that are definitely not user-friendly, since a set of long command line orders and parameters must be typed in your OS console. To solve this issue, it is ideal that you use a proper Graphical User Interface (GUI) for ArgyllCMS. One such tool related to monitor calibration and profiling is DisplayCAL (formerly known as DispcalGUI) developed by Florian Hötch. Just like ArgyllCMS, DisplayCAL is also completely free, the development of which you can also support via PayPal donations.
There was a major change in UI between 2.x and 3.x version, the latter being more like i1Profiler. Also 2.x versions feature an auto LUT loader on startup from profile. That feature was dropped in the first versions of 3.0 (bad) and later moved to DisplayCAL taskbar autoloader, which automatically loads ICM calibration for GPU LUTs in OS configuration (excellent feature). In this article, we will cover the installation and use of ArgyllCMS and DisplayCAL 3.3.1 for Windows, with i1Display Pro colorimeter. It is recommended to get the latest version.
ArgyllCMS and DisplayCAL have lots of options, so this is just a simple guide to cover a general validation mechanism and some particular issues related to Dell monitors.
ArgyllCMS and DisplayCAL Installation
The easiest way to install ArgyllCMS and DisplayCAL is by first downloading DisplayCAL and running its installer. Head on over to DisplayCAL’s website, navigate down to “Get DisplayCAL standalone”, choose your operating system and start the download process for the latest version. I downloaded the version for my Windows 10 64-bit machine. Once the installer is downloaded, go ahead and launch it and follow the standard setup steps. During the install, you will be presented with a choice to let DisplayCAL handle calibration loading:
I highly recommend to keep this option checked. After the installation is complete, go ahead and double click the DisplayCAL icon, which should be on your desktop. As soon as DisplayCAL main window comes up, you will be presented with the following notification:
Go ahead and click the “Download” button, which will start the download process of ArgyllCMS. Once the download is complete, DisplayCAL will automatically handle the proper placement of ArgyllCMS files and the above message will not appear again. Go ahead and close out of DisplayCAL – we want to make sure that it properly loads together with ArgyllCMS, but only after the colorimeter is plugged in.
Now go ahead and plug in the i1Display Pro colorimeter to your computer. As I have pointed out before, the first time you plug in the colorimeter, Windows may want to install it as a HID device. Let Windows do its job. I repeat this here because you may want to validate your monitor in another computer or OS than the one you use with DUCCS. Color Munki Display behaves in the same way, just plug & play. If you want to use i1Pro / i1Pro2, then a USB driver is needed, so make sure to check ArgyllCMS documentation.
The next step is to launch DisplayCAL again. With its default configuration (Settings: Current in the upper combo box), DisplayCAL reads information from default profile associated to a monitor in “Color Management” configuration of Windows Control panel. Validations will run against that display profile.
Before any measurements, you must configure i1Display Pro colorimeter to work with GB-LED technology. This is done with the help of GB-LED spectral samples bundled with DUCCS (or i1Profiler) software. ArgyllCMS knows how to convert SPD stored in “.edr” files from X-rite software to its own text format for SPD with “.ccss” extension. These files are known as “spectral corrections” for colorimeters. You can do this task via “Tools -> Correction -> Import colorimeter corrections from other display profiling software” menu entry. You will see a pop-up window like the following:
The “Auto” feature may find it automatically if DUCCS is installed in your computer (it did on my PC). If that does not work, then click “i1 Profiler” check box and upon “Select file” select i1Profiler setup executable (you might need to download i1Profiler setup from X-rite’s website). After importing spectral corrections for i1Display Pro, you must select “LCD RG Phosphor” (RG_phosphor_family_25jul2012.ccss) in the “Correction” drop-down, which stores a 1nm GB-LED spectral sample for White, Red, Green and Blue channels:
If you see an error related to unknown or unplugged colorimeter, make sure to navigate to “Tools -> Detect display devices and instruments” menu. I would make sure to enable “Options -> Show advanced options” too. The last check is to ensure that “Display” has your monitor selected and “Settings” are still kept at “Current” in the upper drop-down:
Always make sure that you buy a solid measurement device, such as the i1Display Pro colorimeter before you purchase a wide gamut monitor. The main reason is to measure monitor screen uniformity as it arrives and if it is bad or it does not suit your needs, return for a refund or an exchange. Perhaps an NEC Spectraview Reference PA or an Eizo CG have a superb uniformity out of the box, but we are talking about a very different price range here. In my Basics of Monitor Calibration article I wrote a brief explanation about measuring screen uniformity and what to seek, such as luminance differences (expressed in percent) and color differences (expressed in deltaC) of screen zones against the center of the screen.
DisplayCAL 3 offers a uniformity validation against ISO norm 12646. It will divide your screen in 5×5 grid and take a few grey and white measurements for each of these cells. Then you’ll get a PASS/FAIL (green or red color) report for each zone. It’s very unlikely that Dell, LG or BenQ or whatever cheap “XXX” monitor model will pass such tests without uniformity compensation features enabled, and if enabled, you cannot use them in CAL1 / CAL2 (Dell) or it may result in crippled contrast unsuitable for video. If you seek to pass that test as a mandatory requirement, then look for an Eizo CS240 or a high-end NEC PA or Eizo CG monitor.
What we can do is validate the much more affordable Dell models against reasonable “good enough” uniformity values for a monitor designed for photo editing or graphic arts. My criteria are to have overall good brightness uniformity with screen corners, which may go down to -10 to -15%, and color uniformity under 2 deltaC for all cells against the center. Some deltaC in corners may be a little higher than 2dC since that screen zone will be covered with menus, tools or whatever options your image editing software offers you. I certainly do not want a screen with patches over 3 deltaC, so I would return it without hesitation. And if there were too many cells near (or over) 2 deltaC, I would return such a monitor too. It is totally up to you – your mileage might vary. I find such requirements a minimum for a 400-600 dollar 24″ (1920×1200) or 27″ (2560×1440) Dell models. These are not ISO requirements for color critical applications and high-end monitors either, just “good enough” for a monitor of this price range that manufacturers must meet as a minimum.
For what I have seen in person or from owners’ uniformity reports sent to me, lots of BenQ SW2700PT, Dell UP2516D, UP2716D, “ALL” LGs and all bigger screen Dell models of the 2014-2018 family won’t meet even these “low grade” uniformity requirements. Most of them will fail, so return them for refund or exchange if they fail this easy test. It’s not your fault that there is such lack of quality control in these 2015-2018 models. The price of some models has not dropped from Dell’s 2013 models and lots of new models might even have worse quality at a higher price tag!
Uniformity measurements are under “Tools -> Report -> Measure display device uniformity”. A new window will show up with a 5×5 grid. You must remove your colorimeter’s hood and place the colorimeter over one of the grid cells. Then click on “Measure”. It will take a few grey and white color measurements. You must repeat the process for each grid cell, so that the whole screen looks like this:
DisplayCAL provides a feature to validate any display’s ICC v2 profiles and generate an HTML report with results. Unlike other applications, this report also contains information to validate a “neutral grey” calibration or white point closeness to daylight or black body loci. So even if you have a very accurate profile that describes perfectly your monitor behavior (like DUCCS table profiles), DisplayCAL can evaluate if calibration is good (neutral grey to your white point) or let you check if white point is far from its intended value. DUCCS validation feature does not offer this kind of information.
To proceed with profile validation, click the “Verification” button in DisplayCAL. The content below will change and show you several fields:
- The first block is asking you which color patch set you want to measure. “Extended verification testchart” is a nice and fast one. “ISO 12646:2008 color accuracy and gray balance” is bigger and takes more time to execute. Make sure that “simulate white point” option is unchecked (disabled by default on DisplayCAL 3). Do not enable it, since the white point of DUCCS profiles is defined to be a PCS white.
- “Simulation profile” is to evaluate how your profile will perform in a color managed environment. For example, if you did a CAL1 = AdobeRGB calibration and profiling with DUCCS and you set in simulation profile “AdobeRGB 1998” or “sRGB”, validation will try to simulate what a color management engine will do (like Photoshop or GIMP for example). For the first profile validation, I would not set a simulation profile. If you enable a simulation profile and check “Use simulation profile as target profile”, DisplayCAL will not validate your display against your current display profile but simulation profile, as if it was the true accurate description of your display. This option is only useful to validate your display calibration in a non-color managed environment, for example a CAL1 = sRGB for general use or CAL1 = “Custom xy, Rec709 primaries, D65 white and 2.35 gamma” for non-color managed video. Again, for your first profile validation, I won’t use it.
- Keep “Tone curve” as “Unmodified” unless you want to validate a particular gamma in a non-color managed environment.
- Validation is done against “Settings” configuration near the top of DisplayCAL window. Keep it as “Current” if you want to validate a display profile set as a default profile for your display.
Next, click “Measurement report…”. Just like before, it will ask you to name the report first, then once you select file destination and click “Save”, you will be presented with the below screen:
Place your colorimeter (with hood reversed) over that window. Once ready, click “Start measurement”. ArgyllCMS will show several patches of colors and measure their color coordinates with your device (corrected with GB-LED CCSS to be accurate). Darker patches need more time. Please don’t mess around with any applications or the Windows task bar until the whole process ends – you do not want anything influencing the measurements.
HTML validation report is very self-descriptive, with labels and green/red colors. Just a few hints:
- By default, it’s validated on PCS (Profile connection space) discussed briefly before. As a summary, think of it as a neutral ground CIE XYZ colorspace with D50 white. Check “Use absolute values” to go back to actual profile, but there is really no need to do that.
- By default, color coordinates are shown in CIE L*a*b*, referenced to PCS D50 white. You can switch to XYZ, or xyY. Keep in mind that unless you enable another option, they will be coordinates of PCS with D50 white.
- By default, color difference between color is calculated with deltaE2000 which is the most accurate now.
- You may want to enable “Evaluate gray balance through calibration only” after reading your report. It will discover actual deviations of your gray values against the neutral grey color set by your current white point.
- “Evaluation criteria” is set to “RGB” by default. Change it to “RGB + gray balance” to discover problems related to non-neutral gray or inaccurate TRC in profile. It will show a value labeled “RGB gray balance (>= 1% luminance) combined Δa*00 and Δb*00 range”. Each of your gray measurements will have some deviation from a “perfect” grey in a* and b* coordinates (white being a*=b*=0), a*<0 is greener while a*>0 is magenta shift, etc…and for each grey they are more or less low values after a calibration. “Range value” is evaluating grey tints variations of the whole gray scale. If a grey has a more or less “big” shift towards magenta but another grey has a more or less “big” shift towards green, the gray range will be high (bad) because you will notice that pink-green oscillation in a grey gradient. If all your grays have the same shift towards the same color, the range will be lower because your eyes won’t perceive a color oscillation in the same grey gradient.
This evaluation is done against profile TRC data for each channel (which is useful for color managed applications like Photoshop), if you want to check actual “color tint” of grays and its range, then select “Evaluate gray balance through calibration only”. Grey range greater than 1.x values (against true neutral grey, not profile TRC) may be spotted by eye, just viewing a grey gradient in a non-color managed environment. As an example, look at this grey gradient with Microsoft Internet Explorer (MSIE). You need a non-color managed browser like MSIE to inspect it.
These grey range results may be not very good with Dell monitors. The culprit is DUCCS. On the previous page, we discussed that DUCCS only took 14+11+11+11 measurements to capture uncalibrated TRC. In version 1.6.5 it was increased to 24×4 and the a*b* range improved when checked against a true neutral grey. This is a DUCCS issue and not a monitors’ issue, because ArgyllCMS with an AMD graphics card is able to get perfect neutral grey in such monitors. ArgyllCMS can measure up to 96 (of 256 grey values) measurements of each grey, red, green and blue uncalibrated response. That means every deviation is measured, so they could be corrected by calibration curves. If 24×4 patches are not able to get you a good enough neutral grey then complain to Dell or X-rite.
Keep in mind that the bigger the gamut of our target calibration, the worse grey range can be for DUCCS calibrations. If your monitor suffers from this issue with DUCCS, an sRGB calibration will have a better grey range than an AdobeRGB calibration, and an AdobeRGB one will have better grey range than a native gamut one.
- By default, this report will try to evaluate your current white point closeness to daylight locus (“Measured vs. assumed target white point ΔE*00”). You can change it to black body locus. Please notice that if you calibrated to a specific CIE xy coordinates from a measurement of paper white, or if you have an Eizo or NEC whose hardware calibration white was a “visual match” (as discussed on previous articles), then this kind of white point result does not matter, ignore it. Most of you will calibrate your Dell monitors against D65 or D50… or D58 (5800K daylight) target, so this is an interesting evaluation.
DUCCS may fail to achieve the desired white point or get a low contrast value. In the previous section there is a description of DUCCS shortcuts and assumptions that may cause this behavior. Keep in mind that DUCCS properly measures your monitor and it knows if it failed its white point target after calibration, just look for “Measured vs. profile white point ΔE*00” with “Show advanced statistics” enabled and you will see it. DUCCS knows with high accuracy where achieved white point is and stores that information in computed profile. There are no current issues with DUCCS 1.5.x and 1.6.x measuring an GB-LED display, the kind of issues like white point or the previous gray range issues that DUCCS suffered in the past were caused by bad calibration practices encoded in DUCCS, unsuitable for Dell’s current quality control. DUCCS will do the right job for some of them (with a good starting point behavior) and less than good for others (with a bad factory configuration). I’m pretty sure that NEC, Eizo or Bassicolor software make the same assumptions and take the “easy way” to calibrate, at least for grey range problem, but NEC PAs and ColorEdge monitors from Eizo have almost perfect neutral grey out of the box, so these assumptions are “more or less” right. This means too that if you get a bad grey range result with DUCCS, a GPU LUT calibration for Dell’s “Custom color” OSD mode done with Basiccolor Display will get the same or even worse results. Avoid Basiccolor Display with these Dells, since you have to pay for that software and good results are not guaranteed.
- Advanced statistics will show more information, like closeness of actual measured white point to profile white point, grey tones lost by a GPU LUT calibration and other information.
- Reference values and measurements are shown in a table in left and right positions, with delta values to the far right. By default they are L*a*b* coordinates in PCS with D50 white.
- At the bottom there is a CCT plot (not very useful), a gamma plot and gray balance plot (like the one from CalMAN or HCFR). Please notice that input values in those plots are percent values (0-100), not RGB values in 0-255 range.
- At the end you will find a 2D gamut plot for inspection:
Given these indications, the HTML Measurement report is easy to read with lots of useful information not available with other software.
With this method, you can evaluate DUCCS calibration issues by yourself. You can validate hardware calibration and profiles from wide gamut NECs, Eizos (internal colorimeter in ColorEdge CG is not supported by ArgyllCMS AFAIK and may have backlight SPD slightly different from GB-LED), BenQ, etc… You just need to remember to apply GB-LED spectral correction before you measure (older wide gamut monitors may need WG CCFL spectral correction bundled with i1Display Pro software). It does not matter that you get “all green” results from Basiccolor, Palette Master, Color Navigation or Spectraview… if ArgyllCMS / DisplayCAL report an issue, you must put attention to it and examine what’s happening.
Remember that if you set a white point in Color Navigator or Spectraview software by “visual match” or by paper color measurement, you can ignore “Measured vs. assumed target white point ΔE*00” result because you didn’t aim for a daylight or blackbody white.
Without a new DUCCS version that actually fixes these issues, you will need an AMD / ATI graphics card (Radeon or Firepro) or an NVIDIA Quadro to fix these grey range and white point issues with a GPU LUT calibration. With that hardware, GPU calibration will correct white point if needed and get perfect neutral and smooth grey gradients akin to a high-end hardware calibration. This is possible because of high bit depth dithering LUTs inside those graphics cards AND dithering. “Dithering” is a very important feature to encode high bit depth results into graphics card output, as explained before. Later on, you will see how to do this with ArgyllCMS / DisplayCAL.
Update: It looks like the new Geforce 1000 series video cards can be bandless even on extreme GPU white corrections after Mr. Gill patched some issues for NVIDIA in ArgyllCMS 1.9.x. While I have not had a chance to test it, the information seems reliable and Mr. Gill actually changed the code for VCGT profile tag loading into GPU LUT. This only works with DisplayPort or HDMI connections, more than 8bpc configured in nvidia control panel and a monitor that can accept more than 8bit. Otherwise banding is very likely to appear.
Older NVIDIA GeForce or Intel integrated graphics unit (iGPU) won’t be able to fix this issue without suffering banding artifacts in some places of a grey gradient… unless before GPU calibration you have a nearly perfect grey, so you don’t suffer from DUCCS issues and no GPU calibration is needed.
Laptop users are unlikely to be able to fix it, since even with a dedicated Quadro or Radeon GPUs, the HDMI / miniDisplayPort / Thunderbolt outputs on most laptops are driven by Intel iGPU (for Intel laptops) with its low bit depth, ditherless LUTs. This is because laptops are designed to be power-efficient, so a dedicated GPU switch on/off only to assist with calculations and all outputs are driven from iGPU LUTS which are always on. There are some laptops with outputs driven by a dedicated GPU – ask your laptop manufacturer for more detailed information.
DUCCS can make two kind of profiles:
- A matrix profile which assumes perfectly neutral gray
- A table profile that is more complex and accurate with independent TRC per channel. These kinds of X-rite profiles are not compatible with Firefox and other software.
Your CAL1 or CAL2 calibrations may not have a very good grey range, so with accurate TRC profile info, gradients may look neutral with Photoshop color management. That means you need a DUCCS table profile, but you may want to use it with other “non X-rite table ICC compatible software” so this is not a viable option.
There is a solution, to let ArgyllCMS re-capture monitor behavior in a profile without GPU calibration. ArgyllCMS / DisplayCAL offers you a bigger catalog for profile types than DUCCS:
- Matrix+gamma: Matrix profile with assumed perfectly neutral grey and a power law perfect TRC. Not interesting for you.
- Matrix+curve: Same as DCCS’ matrix profile. Not interesting for you.
- Matrix+curves: A matrix profile (easy color management calculations) with independent TRC per R, G and B channels. This is one of the profile types you need.
- XYZLUT+matrix profile: Similar to X-rite table profiles but compatible with Firefox if you enable ICC v4 support. For software incompatible with this kind of LUT / table profiles, a matrix description is included. This kind of profile may be interesting too.
Keep in mind that LUT profiles need a huge number of measurements to be accurate. You are going to capture monitor behavior (CIE XYZ coordinates) for a large set of RGB inputs. This can be visualized like a cube table, a 3D table. For 5 measurements per cube side (5 measures from black to red, 5 from black to green, etc), you need 5x5x5 = 125 measurements to map the whole cube, the whole display gamut with a 4 step cube side. For 10 measurements per cube side, you’ll need 10x10x10 = 1000 measurements. For 15 measurements per channel, you’ll need near 3400 and for 20 it grows to 8000 and so on. Some inner cube measurements can be skipped of course – this is just an easy explanation that for a tiny increase in cube resolution, a huge increase in total measurements is needed.
That translates to more time and that’s easy for a fast device like i1Display Pro, but if you have to measure with thousands of patches with a Munki Display or an i1Pro2, you will need a lot more time. I wasn’t joking when I said that if you need to profile printers, measure fabrics’ color and calibrate displays, you should get both devices: an i1Display Pro and an i1Pro2 (or a used i1Pro for a low budget). It’s not just a matter of speed but of accuracy too as explained before.
DisplayCAL 3 and DispcalGUI 2.6 can do profiling without calibration, but IMHO this is faster and easier to do with DispcalGUI v2.6 because it has a button for that. With v3 you need to change calibration target to “native” in several user interface fields (white point and gamma) and disable interactive adjustment. For this feature, DisplayCAL 3 should have a button just for “profile”, without calibration.
In the “Profiling” block you can configure your desired profile type. A “Curves + matrix” would suit your needs and take less time to do: your display is already calibrated in a LUT3D. Set “Profile quality” to “high” and enable black point compensation (BPC). BPC means that the resulting profile will store a near perfect black behavior. This is less accurate than a measure of your actual black point, but this way color-managed applications will color manage “less” near black colors, so you avoid black crush and dark grey “tint” issues. Black crush issues could be caused because profiles like AdobeRGB have an ideal infinite contrast, its black is a “true black”, so if a color-managed application sees that your display profile darkest black is for example about 0.12cd/m2 (1000:1, 120cd/m2 white), it will crush to R=G=B=0 any color, whose color coordinates are darker than this 0.12cd/m2 black point. You may lose several dark grays, all crushed to your display R=G=B=0 black value.
Dark grey tint could be caused by inaccurate low light measurements of TRC while profiling, so it’s safer to assume that a* and b* color coordinates for near black grays are 0, colorless, so this is another BPC advantage.
XYZLUT profiles could use BPC too. Some advocate against its use in these “table” profiles, because they are meant to be “accurate” but if after profiling a non-BPC XYZLUT profile you notice those kind of issues in Photoshop or similar color-managed programs (dark grey color tint), I would go for a BPC version of your current profile without a doubt.
It is very important that if you choose to create an XYZLUT profile, then click on the gear icon and make sure that “Enhance effective resolution of colorimetric PCS-to-device table” is enabled and “Smoothing” must be enabled too. Otherwise Photoshop and other programs may show “brightness waves” in color gradients.
Next, you should select the test chart for profiling, the set of color patches to be shown in your display and measured by your device. DisplayCAL 3 has an auto feature but you can also copy old charts from DisplayCAL v2 (DispcalGUI) to v3. I would go for “Extended testchart for LUT profiles” that has a total of 175 patches, since you may want to capture the grey range issues that DUCCS cannot solve. You should know that your display might not have a perfect grey, so you want accurate TRC for your display profile.
Name your profile. The default input field for name will account for current “calibration” target (white, gamma, etc), change them or erase those parameters.
After all the measurements are done, ArgyllCMS will compute a profile. When profile is complete, a summary pop-up window will be displayed with sRGB and AdobeRGB intersection with your profile. You can inspect its gamut, TRC and other profile information. Just check “Show profile information” if you want to see that info:
There will be a button for installing the profile on your OS and a selection to install the profile for current user only or as system default.
Make sure that after profile installation you change DisplayCAL to “Settings: Current” (upper combo box).
If DUCCS is unable to give you an acceptable white point or grey range, then you can fix it with calibration curves in GPU LUT. If your DUCCS calibration is OK, skip this section: you don’t need it. As discussed in previous sections, you’ll need an AMD / ATI graphics card or a NVIDIA Quadro (not NVS Quadro) desktop graphic card versions (NVIDIA GeForce 1000 series are an exception). Without this kind of hardware, you may get banding artifacts (I mean you WILL get banding artifacts because you have color tint issues on grays right now). First of all, you must need to know that white point GPU LUT correction lowers maximum brightness output, since we are going to limit one or two channels max output to get your desired white. With GPU re-calibration, you may fix the white point in factory calibrated OSD modes like sRGB or AdobeRGB.
GPU re-calibration is only about white, neutral grey and gamma. You won’t alter your current CAL1 or CAL2 gamut emulation. You may want to disable “Interactive display adjustment”, because you cannot change OSD settings – the same applies to sRGB or AdobeRGB factory calibrated modes.
Change “Whitepoint” to your desired target. For example, 6500K daylight (D65), or 5000K daylight (D50) or CIE xy coordinates of your paper white. No “Visual match” is allowed here, because you cannot change your current monitor’s white with the OSD buttons in your screen for CAL1, CAL2, sRGB or AdobeRGB modes.
Leave both “White level” and “Black level” “As measured”.
For “Tone curve”, select your intended TRC for CAL1 or CAL1 in DUCCS, but for constant gamma values use “Relative” setting.
Do not use “Ambient light level adjustment”, since DUCCS does not use it either (it’s out of the scope of this mini-guide, check DisplayCAL documentation).
I would configure calibration speed to “Low” and leave other calibration options as default.
Some of these options are available only if you enabled “Show advanced calibration options” under the “Options” menu.
For profiling options choose whatever you want, “Curves + matrix” configuration described in previous section will do the job.
Click “Calibrate and profile”. If you didn’t disable “Interactive monitor setup”, click on continue, you cannot change RGB gain and offset controls for CAL1 or CAL2:
Calibration process in ArgyllCMS is an iterative process of measuring monitor’s native TRC and trying to correct it. With each loop, more measurements are taken, narrowing the step gap between measured grays. In the last iteration, up to 96 grey measures are taken to ensure accurate calibration curves. This is a big difference when compared to DUCCS.
When this process is finished, ArgyllCMS will compute calibration curves from measurements and load them into your GPU LUT. At this point, your display is calibrated in GPU LUT, but you need an accurate profile that describes this calibration. Like in the previous section, ArgyllCMS will measure monitor behavior, compute a profile and embed your new calibration curves into it.
When profile is complete, a summary window will show up with sRGB and AdobeRGB intersection with your profile. If you check “Show profile information”, you can inspect gamut, calibration curves (which now won’t be linear), TRC and other profile information.
Just like before, there will be a button for installing the profile on your OS and a selection for installing it for the current user or as system default. Pick the appropriate setting and install the profile.
Make sure that after profile installation you change to “Settings: Current”.
If you chose to use DisplayCAL / ArgyllCMS LUT loader, it will start on user logon. It will check what profile is set as default in OS color management.
If you want a full GPU LUT calibration you can get it in the same way under “Custom color” OSD mode (full native gamut). This way, you can access RGB gain and offset OSD controls of your monitor. ArgyllCMS has no DDC / CI support, so you must manually configure those controls using the buttons in your monitor.
Make sure to enable “Interactive display adjustment” and when prompted for whitepoint adjustment, remember to lower / raise brightness control as you change RGB gain control until you get your desired whitepoint, white level and contrast.
Again… make sure that after profile installation you change to “Settings: Current”.
These GPU calibrations and profiles could be validated in the same way as DUCCS profiles.
That’s all there is to it! If you have any questions, please feel free to ask in the comments section of this article.
This article was originally written in 2016. There are now new models in premium and non-premium market segments. More monitors are out of production like Eizo CS240. Now in 2018, the same uniformity issues we described for Dell or BenQ Or LG wide gamuts are still there in new models so be warned about non-premium wide gamuts.
NEC PAs or Eizo CS models have lower prices than when 2013 Dell’s GB-LED came out. I’ll choose a NEC PA or an Eizo CS/CG over a bigger resolutions model from Dell, BenQ, LG, Asus or any of these brands for the same price range. More resolution does not translate to a better monitor.
You won’t be able to correct uniformity like we fix DUCCS problems with DisplayCAL, it will stay there for all monitor’s life and as the monitor ages, it will get worse. Final choice is up to you, but my recommendation is to avoid low-cost models and get an NEC or an Eizo if you want a real wide gamut monitor.