Tuesday, January 13, 2009


The “prints too dark” problem inadvertently involves almost every aspect of computer image processing, displays, printers and their drivers, color management, and of course image editing. Yet it is just a single issue of prints that don’t match the screen in density/brightness. The explanation of why the problem seems insoluble is that all of these separate but involved functions are the domains of companies which compete with one another in a marketplace that discourages standards. For instance the driver interface for each brand of printer is different, as are the on-screen controls of each brand of LCD display. And of course the people who run these companies and the technical people who design the products do not see reality from the same perspective as users, who of course are an even more diverse population.

However, the “prints too dark” problem is a rather universal shared frustration that reduces individual satisfaction with the digital photo experience. So where do we look for answers and solutions? I have been exploring that with so far little success and a lot of time and effort consumed. Which made me think about what a better digital photo reality would look like, that would not have this problem caused by a differences in the brightness of LCD displays compared to prints on white paper.

That this is a problem is because each brand and model of LCD display tries to be brighter and contrastier than the competition because consumer think they want brighter and contrastier, yet the adjustment controls on every LCD display do not provide users with an exact method to achieve a known, objective brightness and contrast for a specific use like editing and processing digital photos. Those specific performance factors are largely agreed on; and they are a display color temperature of 6500K, a gamma of 2.2, a white luminance of 120.o CD/m2. So if LCD display makers would accept those aim points as standard and provide in the display controls a single option “PHOTO” that would preset the display to output at those levels, everyone would have a similar and dependable way to use their computer’s display to do digital photography more effectively and reliably in terms of results. Of course if LCD display makers offered a standard PHOTO preset, they would also need to provide a display profile file that accurately reflected the display’s characteristics in that PHOTO mode.

However that still leaves a part of the problem unresolved, and that is that an LCD display ideally adjusted, calibrated and profiled, is still brighter in luminance range than what a print on white paper can be, and that differential will result in prints that are 10 to 15% too dark relative to the screen image.

There are two ways to make photo prints. One is to let the printer driver adjust the image values to internal standards determined by the driver to achieve a good print, more or less as the printer designer sees what should be an ideal print image. The other is to have the image editing application from which a photo is being printed control color, which is referred to as a color managed workflow, which is a precise method to match the print output colors to what is seen on-screen. Unfortunately, the printer paper profiles used only contain information to provide color matching, the profile and color managed workflow does not match screen image brightness to print density because there is no density midpoint information in a profile to tell the print driver how light or dark the print should be.

Ideally then the color management system needs an upgrade to include brightness range midpoint matching correction. But such an overhaul of the entire color management system would be a massive undertaking and require possibly years and far too much cost to implement.

An alternative then must be in the hands of the printer companies to add an output print density adjustment for color matched printing in the printer driver dialog. Or color managed photo imaging application software needs to include a way to adjust the midpoint image brightness of the file information that is sent to a printer so a correct print image density is achieved. Implementing this may be most easily achieved with a plugin utility similar but simpler than Photoshop’s output Transfer Function.

How will those who have the means to facilitate a fix for “prints too dark” will respond to the problem remains to be seen. I have done just about all I can in my role as a gadfly to define and describe the problem as I have come to understand it and convey that information by all the means available to me. I am open to discussing the problem and possible solutions, but to be candid, I want a fix I can offer to users who communicate their frustrations to me, as well as a rest from writing about this same thing that has dominated my attention for weeks now. Anyone with a problem or a solution is welcome to contact me at goofotografx@gmail.com, or if more background is needed on the general subject my Digital Darkroom Resource CD is available and is described at: https://sites.google.com/site/davidbrooksfotografx/

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You can also ask questions I will answer privately by sending me an e-mail at: goofotografx@gmail.com