COLOR MANAGEMENT CONFUSION

The last two days have been a bleary-eyed ordeal reading as many forum posts as I could on “prints too dark” from a Google search on that phrase, which obtains almost 2 million results. What I was looking for was as complete a picture as possible why people trying to make photo prints were getting unacceptably dark print output. I didn’t get very far into the almost 2 million results before my eyes gave out reading the forum posts, but I did find that a lot of users have discovered the cause of dark prints is an LCD display that is too bright. But confusion reigns when it comes to how to fix the problem, very often involving color management and the idea of using Photoshop’s “soft proofing”. Some forum gurus have been recommending adjusting the display brightness to match the print output, and actually that practical philosophy was used before there was such a thing as Color Management, but it largely precludes color matching using CM and a calibrated and profiled display, if in reality an LCD display can be reduced in brightness to actually match the range of print densities or the CRT monitors of the past. Some users found that instead of having their photo editing application control color, select having the printer driver control color, which with some printer drivers does provide an output print density adjustment and yields satisfactory print brightness results, but the downside is that some printer drivers will automatically adjust print density and others don’t, as well as color matching with what you see on-screen is not usually supported.

So, let’s try and reduce the confusion about “prints too dark”. In most cases those who have guessed it is because their LCD display is too bright are correct! (And I’ll get to how that can be dealt with later). That Color Management is the problem or the solution is really just a bad detour. The reason is that CM only deals with matching colors between devices with profiles, and device profiles don’t have any overall density information in them, so no effect on image midpoint setting that controls the brightness appearance of an image, in a print or on-screen - just color information only. So the use of soft proofing is not a predictor of image density, because the soft proof is being viewed on screen in the brightness range of the LCD display that was used to perceptually adjust the image file data as to how bright or dark the image should appear. The same applies to any on-screen preview image, like in Photoshop CS3 and CS4 that has Color Matching for the preview image in the Print dialogue window, it will give you a look at how the colors will print but will no predict print output density.

There has been some discussion in the forums about the display gamma setting in connection to some schemes to resolve the “print too dark” issue. With Apple recently changing to a display gamma default of 2.2, that 2.2 gamma is now a universal standard, and Apple finally changed probably because internet pictures, like photos in FaceBook don’t look quite right on a display at at 1.8 gamma, as well as the fact that photos on the internet are usually uploaded as JPEG/sRGB images and the gamma imposed by sRGB is 2.2. So, with display gamma default now universally 2.2, using any other display gamma to achieve a less bright display to correct “prints too dark”, could become a problem if the images are uploaded to a web site, or sent to an outside print service. They won’t match the density you saw on screen.

To deal with the high brightness of LCD displays and to also obtain color matching in output users first need to calibrate and profile their LCD display. Ideally using a good hardware sensor that measures the display output is ideal, either an X-Rite i1 Display 2 (or equivalent) and a DataColor Spyder3 Elite are two I can recommend. But if that cannot be afforded, for Apple users in System Preferences/Diplay/ there is a calibration and profiling utility, and any Windows user with any version of Adobe Photoshop will have Adobe Gamma.EXE installed on their system, so learn how and use these utilities. Although some forum posters have claimed setting LCD displays with a white point luminance as low as 85.0 or 90.0 CD/m2, the level of a CRT. I have not found with a luminance level that low that photo image screen quality is acceptable, if it can be done at all with 2.2 gamma. The color management industry recommendation is for color managed functioning set the LCD display white point luminance at 120.0 CD/m2, and from experience i will have to agree. I don’t have a too dark print problem with my LCD’s set at 120.0 CD/m2, but it is still 25% brighter than a CRT, and if prints are still too dark, an inexpensive solution would be to cover the front of the LCD display screen with a neutral density gel. These are available from Lee filters, go to: http://www.leefiltersusa.com/go.php

Obviously in a blog I cannot take the space to detail a workflow that I have found successful, and I’ve done that already, and it was published in the December issue of Shutterbug on page 68. you can access the article on-line at Shutterbug’s site at: http://www.shutterbug.net/techniques/pro_techniques/1208printing/index.html

Note: in the article the Photoshop screenshots illustrating the use of the Transfer Function weere from CS2, with CS3 go to the upper right of the Print window and click on Color Management and then the Output option tag to find the Transfer Function button below.

If you are still needing more Color Management information or help drop me a line by e-mail at goofotografx@gmail.com

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