In this article we’ll examine three basic factors related to setting up a home digital darkroom that tend to generate many questions and some debate: Environment, Display, and Photoshop’s Color Settings.
The digital darkroom, like the traditional wet darkroom, should be a comfortable place that encourages relaxed and focused concentration. Environmental lighting, which is often overlooked, is very important. Room illumination should be consistent and relatively low intensity. You’ll find it easier to judge images, both on the display and when printed, if the brightness and color temperature of the environmental lighting does not fluctuate.
Maintain a relatively dim working area around the display and avoid reflections on the display’s surface from lit walls or windows. Windows in a digital darkroom are best avoided. If you have windows consider installing blackout shades (available at home improvement stores).
Be conscious of wall color, especially the surface immediately behind the display or any wall that may reflect onto the display (it will influence your judgment). White, off-white, or neutral gray is ideal. And, by the way, it is also a good idea to wear a black top when working on image files; shirt color can reflect into the display surface.
You’ll need a viewing light for evaluating prints. A professional viewing booth (GTI, JustNormlicht) is ideal. (Fig. 1) Less expensive alternatives are Ott-Lites and Solux lighting. Ott-Lite fluorescent are commonly available. You may need to shop for the halogen Solux on the Internet. Solux sells a track lighting kit that is excellent for illuminating a print viewing wall. (Fig. 2) We’ll have more to say about print viewing lights in the next section.
You should consider the display, video card that runs the display, and a display calibration/profiling kit as a single unified system. It is virtually impossible to calibrate and profile a display by eye. Without accurate calibration and profiling it is not possible to achieve a predictable match between an image viewed on the display and a print.
Most digital photographers now use quality LCD displays. The Apple Cinema is a “best buy” and the more expensive Eizo displays are excellent. (Fig. 3) Do not purchase inexpensive LCD displays. They are difficult to calibrate and profile, and have other issues—a narrow angle of view, for example—that can severely limit their usefulness in a digital darkroom.
Be sure the computer’s video card is designed to adequately manage the flow of data to the display (video cards can be replaced when necessary). Large displays—or if you use more than one display (excellent for creating more desktop “real estate”)—require better video cards.
If you cannot trust the image on display nothing else really matters. We strongly recommend routinely using a calibration/profile kit. (Fig. 4) These kits use a color meter “puck” or “spider”, are reasonably priced and easy to use. The ColorEyes/Spyder3 Bundle (http://www.integrated-color.com) is a good value (the ColorEyes software is excellent). (Fig. 5) These kits feature a “wizard” software interface that conveniently walks you through the process of first calibrating, then profiling a display.
The wizard is used to adjust the luminance (often incorrectly called “brightness”) of the display and to select both a gamma and white point setting. Confusion about these choices is common, in part because they are arbitrary. Simply keep in mind that the aim of any combination of luminance, gamma, and white point is targeted to matching what you see on the display with what you see in the print.
Luminance. Luminance is specified in candela per meter squared (cd/m2). Don’t worry! This is just a unit of measure, like feet and inches. Lower cd/m2 translates into a less bright display; higher cd/m2 indicates a brighter display. LCD displays are typically very bright out of the box and need to be dimmed to present images on-screen that will better match prints. If your display and/or kit software offers a minimum luminance setting, use that for the first calibration/profile. If you are asked to enter a value, try 120 cd/m2. Almost all LCD can be calibrated/profiled at this setting. (If you can go lower, do so.)
You can imagine luminance as the volume or density of perceived light. With all other variables held constant (environmental lighting, for example) an increase in the density of light is visually experienced as “brighter” or “lighter”; a decrease is the opposite.
Gamma. Gamma (also called contrast by photographers) is built into almost all imaging systems (computer displays, televisions, motion pictures, film, and digital camera software, to name just a few). Gamma is designed to mimic the non-linearity of human vision and is expressed as a number: 1.8 and 2.2 describe the traditional native contrast of Apple and Windows operating systems, respectively. In practice your eye will quickly adapt to either setting but we recommend using gamma 2.2.
In the wet darkroom it is always desirable to first determine the overall density of a print before adjusting contrast. Essentially, and in very different ways using very different technologies, we are achieving the same goal when calibrating/profiling a display. We establish density by adjusting luminance, then tweak contrast by adjusting the gamma.
White point. White point describes color temperature measured in degrees Kelvin. D50 and D65 are common choices. Lower Kelvin numbers indicate increasingly warm light (yellow) while higher numbers describe increasingly cool light (blue). The ideal white point would match the display to the paper white of a print viewed under your print viewing light. If the calibration/profiling software allows for manual input, try 6000 degrees Kelvin. If not, D65 is a good starting point.
There is a very important relationship between the display and viewing light (and both are affected by the environment). You will be viewing, judging, and comparing images both on-screen and after they’re printed. We’ve found 6000 degrees Kelvin to be a good match for Solux lighting, and D65 a better match for Ott-Lites. Or, if you invest in a viewing booth choose the white point that matches it’s color temperature. You can always author multiple display profiles. Make a few prints and place them under your print viewing light. Compare the illuminated prints to the image on-screen. Open the Display panel in the system software and alternate between display profiles. Visually determine the best match and make that your standard display profile. While this is an excellent process–one based on using and training your eye to look closely and critically for the nuances that greatly impact print quality–it is predicated on making test prints using accurate ICC profiles.
You’ll discover that some combinations of luminance, gamma, and white point work better than others. It is most important to be consistent with these settings. Once you’ve found a combination that works only make changes when you have a good reason to do so.
Incidentally, Gretag-Macbeth’s i1 (Eye- One) kit uses a spectrophotometer instead of a color meter. Spectrometers read more data and are therefore more accurate. (Fig. 6) They can also be used to author very good ICC printing profiles. While more expensive these kits are an excellent value in the digital darkroom. Authoring your own ICC print profiles makes it possible to work successfully off the OEM (original equipment manufacturer) path; you can use third party papers and inks, for example.
Remember: the point of building accurate display profiles is to improve the match between an image on-screen and the print from that image file. This is easily negated by poor environmental control and poor lighting, especially for viewing prints.
With a properly calibrated/profiled display the first order of business in Photoshop is to configure Color Settings (Edit>Color Settings). (Fig. 7) Photoshop is a powerful application that can be used for many different tasks; we need to configure it properly for the digital darkroom. There are two variations, depending on the quality of your print profiles.
Generic Print Profiles:
Generics include the profiles added to your computer system during the print driver installation and profiles downloaded from the Internet (regardless of source, free or otherwise). They may or may not be ICC:
Working Spaces sub-panel. Use Adobe RGB (1998) for the RGB working space and Gray Gamma 2.2 for Grayscale. Don’t worry about the CMYK or Spot selections; we’ll not use those in the digital darkroom. Color management Policies sub-panel. The conservative choice in this sub-panel is to select Preserve Embedded Profiles in each menu and keep all the radio buttons clicked on. If you open an image file tagged with a profile not matching the Color Settings selection, Photoshop will automatically launch the Embedded Profile Mismatch panel, giving you a choice for which profile to work with. (Fig. 8)
Conversion Options sub-panel. Keep the Engine on the default setting, Adobe (ACE). Select Perceptual from the Intent menu. Keep both radio buttons clicked on. Advanced Controls. Do not click on Desaturate Monitor Colors By. It will lead you down a path of false color. Click on Blend RGB Colors Using Gamma and keep the default setting, 1.00.
Accurate Print Profiles:
Accurate print profiles are always ICC and specific to a given printer, ink, and paper combination. They can be self-authored using something like the i1 kit hardware and software (or better). Or, you might pay someone else to authoring them for you. This configuration of Photoshop’s Color Settings is identical to the above with two exceptions: use ProPhoto for the RGB working space and select Relative Colormetric from the Intent menu.
As with the luminance, gamma, and white point settings selected when calibrating/profiling a display, there are other RGB and Grayscale Working Space profiles that can be used in the digital darkroom. You can also work with different Rendering Intents. Intents instruct Photoshop how to map or render out of gamut colors (an image file may contain color information that cannot be duplicated by the printer/ink/paper combination being used).
As your expertise deepens experimenting with other Working Space profiles and Intents makes sense. If you find one that works better, by all means use it. Just be consistent. You’ll create a “performance baseline” that will provide a foundation for experimentation and refinement.
When the Color Settings are configured click the Save button in the upper right corner and all the selections will be grouped together and saved. It’s a good idea to check the Color Settings in Photoshop before editing image files (especially if other people have access to the machine or you’ve relaunched the application).