What target settings for LCD monitor calibration?

[_Murat_Cuhadar_]

I have recently installed Spectraview II to calibrate my NEC LCD 2180WG monitor but have some doubts on which target settings to use as there are different opinions on color temp, gamma and intensity choices.

I use my system purely for photo post-processing and printing on color calibrated printers. I use AdobeRGB color space and have no interest for processing images for web.

- What color temp do you use/recommend? D50, D65 or something in between? I see that some folks use D65 and others swear by D50.

- What about Gamma choice 1.8, 2.2 or L* ? Same here, no common choice here too.

- Lastly what about intensity (brightness in terms of cd/mm2)?

NEC recommends Target Settings for Printing, which are D50, 1.8 gamma and Max. Intensity, but I'm not sure.

I'd appreciate if you could recommend correct settings for my type of work.

Thank You

[Lou Dina]

Murat,

Gamma basically establishes the tonality (brightness/darkness) of the midpoint of your tonal scale. Most people recommend a gamma of 2.2 (which is becoming the standard, and is a good choice). Others recommend native gamma (I don't).

I use a gamma of 2.0 on my LCD monitor, which is a little lighter than 2.2, but through trial and error I find it gives me a closer match from monitor to print. I use a special viewing target to help me assess the final calibration, including white luminance, black luminance and gamma. For my setup, I use a white luminance of 85 cd/m2 and a gamma of 2.0. Your system may be a bit different.

For monitor to print matching, I would definitely keep your luminance below 100, and 2.2 is a good overall choice for gamma. I set my monitor to a color temp of 5100K, which is warmer than a lot of people use, but again, it gives me a nearly perfect color match, using industry standard viewing lights.

Lou

[Guest]

Native anything within calibration tells the software to do no adjustments the video card to correct for that specific current condition.

If native gamma of your particular display happens to be 2.0, the software will leave it as such and write it within the profile so CM apps can adjust previews of images tagged with any given gamma written into their profile.

The issue you'll run into with this approach is nonCM apps are going to display sRGB web color images a bit lighter.

[Larry Tseng]

Murat,

I use Spectraview II on an LCD2190UXi and the native gamma comes pretty close to gamma 2.2 if I am not mistaken. In any case, I don't think you will see any difference with any setting that you choose since SpectraView adjusts the LUT on board your LCD2180WG (and leaves the video card LUT at neutral). The choices, I think, are really for non color-managed situations, e.g., DICOM for medical displays. I leave mine at gamma 2.2 to better match sRGB images on the internet since I don't expect to run into color managed images much.

If you are using a color managed workflow, just pick something and forget it.

Larry

[Guest]

That's right he's got a SpectraView. I forgot about how they work with display's LUT rather than the video card's.

Follow Larry's advice because I can tell when I leave my iMac or Samsung at native gamma with the no gamma curve downloaded to the video card both displays are butt ugly both showing duotone grayramps with the iMac so contrasty about half of the highlite region is blown completely white.

[Lou Dina]

Larry,

If you don't object, send me your email address. I'd like to email you something off line. My email address is listed under my profile.

Lou Dina

[Larry Tseng]

Second thoughts on what I said earlier (and maybe more -- after Lou sends me his stuff):

> If you are using a color managed workflow, just pick something and forget it.

Native Gamma may not be a good choice because SpectraView II can make corrections to as small a step as 1/256 of the intensity range to the on-board LUT. I can see from my LUT correction data that a profile that works off of fewer patches will have trouble accounting for the local spikes and an ugly curve in the very deep shadow region. So it would seem best to provide the profiler with a smooth gamma characteristic to profile.

I would stay away from the extreme gammas though, say 3.0 or 1.0, since this will wreck your desktop.

Larry

[_Andrew_Rodney_]

>Native Gamma may not be a good choice because SpectraView II can make corrections to as small a step as 1/256 of the intensity range to the on-board LUT....

True! For this unit, not a benefit nor necessary.

[_Brett_Patching_]

Thanks everybody for a really informative thread. I have a beginner's question:

If I calibrate my screen to, say, 5100K and 2.0 gamma, what relationship does this have to the colour space I choose in Photoshop? I have read that Adobe RGB (1998) has a D65 white point and assumes 2.2 gamma, whereas Adobe Wide Gamut and ProPhoto have D50 white points.

If I have calibrated my monitor to 5100K, should I choose a colour space with the same white point?

Thanks,
Brett

[Lou Dina]

Brett,

Not required. Pick a color temp that gives you the best monitor to print match for your monitor, viewing lights, etc. For me, that is about 5100K to 5200K. Some people seem to like 6500K, but I find it way too blue. Use what works. If you find your prints are too yellow compared to the monitor, then your monitor color temp is set too high. This assumes, of course, you are comparing your monitor to prints made using a good custom printer profile for your printer/paper/ink combination.

I work in a number of different color spaces, including sRGB and Adobe RGB, both of which are 6500K spaces. Using a different color temp for monitor calibration is not a problem.

BTW, I have suggested a 2.0 gamma in the past, but discovered an anomoly with the program I was using to load the calibration into the VLUTs and compare gammas (DisplayProfile.exe by Gretag). I now use 2.2 gamma since it is the Windows and internet standard. The profiling software corrects for gamma, so you will get the proper tonal distribution with either gamma in color managed applications, but you'll be better off with 2.2 gamma in non color managed applications.

Lou

[_Brett_Patching_]

Thanks for your quick reply Lou. Would you also recommend 2.2 gamma for non-colour managed applications on Macs? Do you know if Apple has moved away from 1.8 gamma?

/Brett

[_Charles_Tintera_]

Just by way of comment - looking over a friend shoulder I was surprised to see that his color settings (in Photoshop) included the monitor profile for his Apple Cinema display(s).

My ACDs are similar to his and do not have functional brightness/contrast/color temp settings so for CM/PS I use the "native" setting - while he prints thru a RIP and I do not I may have to try his setup.

cvt

[Lou Dina]

Brett,

In general, 2.2 gamma has become more of an accepted standard. Even a lot of Mac users use 2.2 gamma. The internet is based on sRGB and that is 2.2 gamma too. Since there are a lot more PC users than Mac users, this seems like a reasonable approach. Also, monitors native gammas are usually closer to 2.2 than 1.8, and often higher than 2.2.

Actually, one reason I calibrate to 2.2 is for non color managed applications. Less tonal shift.

Lou

[_JayM_]

"My ACDs are similar to his and do not have functional brightness/contrast/color temp settings so for CM/PS I use the "native" setting - while he prints thru a RIP and I do not I may have to try his setup. "

With this being the case (no dedicated brightness/contrast controls) how do you calibrate your monitor's white and black luminance points?

[Lou Dina]

Jay,

I use LCDs with a digital video card. Most LCD monitors, except the higher end units, write adjustments to the video card, even when you are adjusting contrast, color, etc, from the monitor controls. The only real analog control is the backlight brightness. This affects mostly the white luminance, but it also can affect the black point. My digital video card knows that there is only one real analog control, and it disables everything but the brightness during calibration, since all other settings get sent to the video card anyway. So, it takes its lead from the profiling software.

Some software just allows you to set the white luminance, and the black luminance falls where it falls (EyeOne Match, ProfileMaker, and probably quite a few others). But some software (ColorEyes and BasicColor come to mind) allows you to set the white and black luminance independently. If you want that type of control, you need to buy the right software, or buy a high end LCD monitor that has more adjustments that are handled outside of the video card.

Up to this point at least, I am not a big fan of using native settings for either color temp or gamma. I prefer to select my own color temp for a better monitor to print color match. And for gamma, I prefer 2.2 so non color managed applications will render images closer to the original intent (since sRGB is the web standard and is used by the majority of non color managed applications).

Lou

[_Andrew_Rodney_]

>But some software (ColorEyes and BasicColor come to mind) allows you to set the white and black luminance independently.

How do they accomplish this considering there's no control over black (just backlight intensity)?

[Lou Dina]

How do they accomplish this considering there's no control over black (just backlight intensity)?

How? I don't know or care, as long as it works and is reasonably accurate. Both ColorEyes and BasicColor allow you to specify separate values for white and black luminance as targets. I assume the software writes corrections to the vlut to raise the black luminance to the number requested in the software. Of course, it can't give you a lower black luminance than what is displayed, so if black luminance is read as 0.4 cd/m2 during calibration and you ask for 0.25 cd/m2, you are out of luck. Best you can possibly do is the blackest the monitor displays at a given backlight level. I do know that both ColorEyes and BasicColor write a separate black point tag to the profile, (which you can see in ColorThink), which EyeOneMatch and PM5 do not do. Also, they report back the final achieved black luminance at the end of the calibration/profiling process. It usually isn't exactly what you specified, but is usually quite close, and certainly provides more control. Specifying different black luminance values definitely gives a different result, which the software reports, and is also visible in the final display when the profile is activated.

Lou

[_Andrew_Rodney_]

>How? I don't know or care, as long as it works and is reasonably accurate. Both ColorEyes and BasicColor allow you to specify separate values for white and black luminance as targets.

I suggest you find out. Think about it; what's there in the black to adjust? You can adjust the luminance yes. If some black is being adjusted, its certainly not a physical adjustment but another LUT tweak. Fine for high bit units, not so hot for those that only provide 8-bit corrections to the LUT.

[_Charles_Tintera_]

Maybe it's a VooDoo adjustment :)
cvt

[Lou Dina]

No need to find out, Andrew. Works just fine as far as I am concerned, and a lot of other professionals as well. Of course it is a tweak to the LUT.

If you spend your days staring at Grainger Rainbows, gray ramps, inspecting for subtle hints of banding, etc, perhaps it is a big deal. For design work, fine art output, lightjet and press work, it works just fine, even on 8-bit displays. Having a perfectly smooth ramp pales in comparison to having well set white and black luminance and a color temp that gives a good color match. Besides, you well know that getting a perfect monitor to print match is not achieveable anyway....RGB vs CMYK, light vs ink, you know the drill.

For those who want the ultimate, high end monitors with external adjustments are the way to go. I have no problem with reaching for perfection, but I doubt it would improve most peoples' results. My monitor to print match is about as good as it gets already.

Egghead discussion over.

Lou

[_Andrew_Rodney_]

As long as you're happy with the science fiction. Least we forget your own words:

>But some software (ColorEyes and BasicColor come to mind) allows you to set the white and black luminance independently. If you want that type of control, you need to buy the right software, or buy a high end LCD monitor that has more adjustments that are handled outside of the video card.

Do we really need to buy the right software? You seem to correctly imply that a high bit display with internal control is different and I'd agree. Otherwise, I think there's something happening under the hood neither of us fully understand and the recommendation may be premature no?

[Lou Dina]

Andrew,

Things that work fine can hardly be termed science fiction. It's not premature if it works, is it? Do you understand everything about how high frequency waves reach your cell phone and magically turn into a voice? Is that "science fiction?" Must be, if you don't understand it.

JayM asked a specific question about setting the black luminance independently of white luminance, and I gave him a specific and accurate answer to his question. Here's his post:

"JayM - 6:43pm Jan 22, 08 PST (#36 of 43)
With this being the case (no dedicated brightness/contrast controls) how do you calibrate your monitor's white and black luminance points? "

The answer, as stated previously, is either a software solution, a hardware solution, or both, and yes, a high bit, high end monitor with external controls will give better results. I'm not promoting or advocating any particular software or hardware, and certainly not for personal gain, unlike some people who hang out on this forum. Just trying to give accurate, unbiased answers when I have something meaningful to contribute, and learn from others. High end monitors are superior, and if you have unlimited resources, why not? But I doubt it would improve most peoples' results unless their current monitor is substandard or poorly calibrated.

Nothing I stated is inaccurate or misleading. Let's try to answer peoples' questions, which if I recall, is the main purpose of this forum.

Let's move on.

[_Andrew_Rodney_]

IF you're convinced it works great.

[_nils_am_]

It works for me. I use it to set the black point of my secondary monitor (that actually can go lower) to the bp of the primary.
That's how I understood the feature to be used. Whatever it does to the LUTs it doesn't hurt so much on the secondary.
Besides, on a different note - what's a desirable black point level anyway? I guess it shall be a little lower than the darkest printed rich black one would encounter? Which would be... an inkjetprint on glossy stock? Offset print? Where would these end up compared to the 0.xy cd/m2 of a monitor?