Saturday, March 31, 2012


David B. Brooks - March 2012
In recent questions and answers in Shutterbug Digital Help there has been a concentration of interest in LCD displays, color management and printing reproduction problems. For me it began to show up about five years ago when there was an eruption of complaints listed from numerous sources on Google about “my prints are too dark”. I began to investigate what the dark prints problem was and what might be causing the problem. In the beginning there was no apparent and clear picture, it was complicated with few common elements. Some were blaming color management directly or indirectly, but that was obviously not an answer although color management was affected by the problem. The reason was that color management and the use of profiles does not involve the lightness or darkness of print output. That is entirely a function of the brightness and contrast adjustment stored in the image file that is being printed. It was not a printer or print driver problem because there were no commonalities, all printers and drivers were involved in the problem and these same printers and drivers were also used without a print too dark issue.
This concentration of interest is due to what the display and computer industry offers and what the digital camera industry develops and promotes, as well as a practice of denial by many major players in the industry, including Adobe, Intel, Microsoft and Apple, just to name a few. They do not admit that there is a problem of “prints too dark” even though early in its development Google had millions of hits on the subject posted on their web site.
Why there is a problem is because the color management system (ICC) was designed when only CRT monitors were used with computers, and incidentally the average brightness (white luminance) at about 90.0 CD/m2, if the monitor was adjusted to 6500K color temperature. The coincidence is that 80.0 to 90.0 CD/m2 is a match to paper white. So a correlation between a screen image with a color managed system and a color print output came about naturally some years ago.
The prints too dark problem arose as CRT monitors were displaced by newer LCD displays, which are generally much brighter with a higher white luminance compared to CRT monitors. Without adjustment of the white luminance, photographic images edited and adjusted using an LCD display that’s too bright and recorded by the image file. So when printed by a color managed workflow the prints were correspondingly dark. That may seem counter-intuitive, but it is not considering the process. If the image was edited and adjusted on a display brighter than paper, when it is sent to a printer driver the RGB positive is inverted to a CMYK image that tells the printer how much ink to put on the paper. But if the image file assumes the paper is brighter than reality, too much ink is applied to normal brightness paper.
This problem becomes even more complicated by how camera companies function in what they provide photographers. For snap-shooters using point-and-shoot  cameras a JPEG/sRGB file is adjusted in brightness by the camera’s processor assuming the real, true brightness of paper, so if the file goes directly to a print service the printing machine applies the correct amount of ink for the brightness of the image. If the photographer has a typical home/office computer with an LCD display and opens the image to edit it with an application like Adobe Elements, Lightroom or Photoshop; they are all color managed applications which adjust the Adobe working space to match the display profile. If the computer is not display color-managed then the Adobe applications matches to the generic profile installed by the computer/display. If the display has been adjusted, calibrated and profiled at a bright luminance setting, the color-managed display is for a color set that is greater than paper, so it will be skewed. In either case color matching becomes dubious; but as long as the working space is sRGB and the image from the camera is sRGB, color divergence may not be very apparent. But if the Adobe working space is set for printing (Adobe RGB 1998), then both the color range and brightness are off, plus an sRGB display will only reproduces 2/3rds of the color in Adobe RGB.

A similar situation exists if a photographer uses a dSLR camera and saves in Raw format. Then even if Adobe RGB workspace for printing is selected, if the LCD display has only an sRGB color range, of the possible colors in the image will not be reproduced on-screen. And if the screen is not adjusted to the equivalent of 80.0 or 90.0 CD/m2 white luminance, profiling of the display may be skewed in addition to the image being edited for a greater brightness than printing on paper matches.
Many in the industry understand that standard home/office computer displays involve a multitude of contrary catch 22, problems relative to their use for digital photography. So if that were admitted would photographers buy these computers and image editing applications and adjust their photographs perceptually on-screen? Maybe not, some wouldn’t. Some would just use JPEG/sRGB save and send their images unedited to a print service. But many photographers want to fix errors in photographs, crop them, and combine them together, or whatever “magic” is offered by application sold to them. Some would also like to print their own images for Christmas cards or birthday greetings, so many things people like to do like sharing images with relatives and friends.
But when a photographer buys a home/office computer most may not be aware that there is nothing in the computer that has any data as to what the color content as seen in the display is and what the colors are according to any standard. There is a general conformity that the red, green and blue data in image files is reproduced as such by computers. And that is why display management software and hardware, a colorimeter sensor to measure the display are offered. These display management devices do two things: 1. Calibrate the display and provide a data file adjusting video output so it conforms to the ICC (International Color Consortium) standard RGB colors. The calibration file goes into the computer’s boot-up folder and is started when the computer is turned on. 2. The display is measured exactly as it reproduces a pattern of standard ICC colors and records variations from the standard in a text file called a profile. This file is placed in the operating system color profile folder, and is activated as the display’s default profile. This profile is referenced by color managed applications like Adobe, Elements, Lightroom and Photoshop and is used to adjust the video output to conform to the working space profile selected, like Adobe RGB (1998) or sRGB. Although some of the newest display management software has automatic display control, many home/office displays do not have supporting DDC (Digital Display Control) that will allow ADC activation and display adjustment. So many LCD displays, even if color managed, may not be adjusted for the white luminance that matches paper white, it’s not easily done manually with good success.
Most home/office LCD displays are very bright compared to CRT monitors from the past, with maximum white luminance as high as 400.0 CD/m2. If this brightness is lowered to 80.0 or 90.0 CD/m2 white luminance, if it can be decreased that much, very often the color reproduction is adversely affected and distorted.
For photographers who use dSLR cameras and save images in Raw format there are only a very few pro graphics LCD displays that both reproduce nearly all of the Adobe RGB (1998) color gamut range, and will adjust to 80.0 or 90.0 CD/m2 white luminance and reproduce highly accurate color, they are:
1. The Dell Ultraharp U2410 24 inch 1920x1200 pixel LCD display.
2. The LaCie 324i 24 inch 1920x1200 pixel LCD display.
3. The Eizo Nanao Coloredge and both Flexscan S and SX display models in all sizes.
4. The NEC Spectraview model displays in all sizes necessarily including the Spectraview software and a supported colorimeter.
Current display management systems include: X-Rite i1 Display Pro, Data Color 
Spyder4 Elite, and the ColorEyes Display Pro software and a supported colorimeter. 
Some photographers may be lucky and avoid problems like “prints too dark”. Others may just give up and loose interest. The rest we have heard from, often completely confused by every difference of opinion there is on all of the photo web sites. If the display is color managed with calibration and profiling at a brightness with a greater white luminance than 80.0 or 90.0 CD/m2, then the profile does not match the colors that should be reproduced in a print. In other words a bright LCD display that is calibrated and profiled will not reproduce color-managed print output in either print density or color that matches the image displayed on-screen.
However, I am not alone on this issue. Good answers are available from dozens of color management shops around the country, from both NEC Spectraview and Eizo Nanao display dealers located in most major cities, from the professional departments of some large camera stores and pro labs, as well as in the accredited schools of professional photography; not to mention the many individual photographers I have become acquainted with. I seem alone on this in the press largely because enthusiast photographers do not frequent expensive professional services, and Best Buy has no solutions, just standard home/office computers. 
This is not just a problem for serious photographers, it is an opportunity. Many serious amateur photographers want to understand and get the best results available to them. In the last five years since “my prints are too dark” made me do some frantic searching and investigation the digital photography and personal computer markets have changed. With cameras there are ever more varied choices, but selecting a computer that will support digital photographic editing and processing is a not even a fair crap shoot. Most home/office computers will handle JPEG/sRGB snapshots and sharing images with friends and family in many different ways, by e-mail, in slide-shows, or on a public web site. But doing any serious image editing although possible opens up complications. For instance, although Adobe and other software vendors do not tell you; Elements, Lightroom and Photoshop are color managed applications; and that really demands calibrating and profiling your display. If you don’t you also do not get an accurate image of your photo on-screen according to any color standard and if sent in an e-mail the picture may not look like what you saw on-screen when it arrives on another computer.
If you buy an advanced dSLR camera and want to reproduce the best image qualities it offers, a companion computer must be even more capable and specialized than most off-the-shelf store models are.  If you want to use the Raw digital camera format, then most of the displays on home/office computers available today will only reproduces 2/3rds of the color variations captured by the camera. If you want to make prints that duplicate the image you see on-screen, the LCD display has to be adjusted to a brightness that matches that of paper-white in printing paper. This along with a color range that reproduces Adobe RGB in Raw camera files is only available with a very few professional grade LCD displays.
Digital cameras and computer have little in common. But the basic rationale and practical considerations that apply to choosing a camera also apply to choosing a computer to do digital photography processing and editing. First you determine what kind of photography you want to do. Then you select how you want to use the resulting images. Then you select a camera and accessories that will accomplish that within your budget. The more advanced and sophisticated you want to get with photography the more you need to acquire a sophisticated camera type, make and model to select and buy, usually at a high cost. These same considerations apply to a computer you may want to use to do your digital photography processing and editing – the two technologies need to parallel each other to accomplish success with both.