What To Look For in Monitor Color Calibration And Profiling Tools
By Michael Walker
Recent years have seen a proliferation of display calibration choices, particularly at the low end of the market, though as always you only get what you pay for.
At the budget end of the market are complete hardware and software bundles comprising a measuring instrument and software that works with that instrument only. Higher-priced offerings tend to include software that supports a variety of measuring instruments and this software may also be available separately if you already have a supported instrument. In both instances the measuring instrument is usually a colorimeter, though products that support printer profiling too, such as the X-Rite ColorMunki and i1 Profiler, bundles provide a spectrophotometer instead.
Colorimeters measure colors via red, green and blue filters, while spectrophotometers read the complete visual spectrum (and beyond). For printer profiling you will need a spectrophotometer, but colorimeters are thought to be better for display profiling as they can read very low luminance levels more accurately, which is important for setting the black point (see below).
High-end displays that feature internal ‘hardware calibration’ include dedicated calibration software in the price; bundles that also include a suitable colorimeter may be available as an extra cost option.
The products that are available in software-only versions, such as basICColor Display, can be thought of as ‘upgrades’ to the cheaper alternatives as they provide better quality and more options. They typically support only the higher quality measuring instruments, though. If you plan to buy a cheaper bundled solution and upgrade it later with better software, make sure first that your proposed ‘upgrade’ software does support the measuring instrument in question.
There are several settings and options that your display calibration software should give you:
Color temperature: as a bare minimum, a screen calibrator should allow you to specify the white point (color temperature) and tonal response (gamma) setting you want to use. Budget products may simply refer to ‘warm’ and ‘cool’ options. More professional offerings will offer graphic arts standards D50 and D65 or options for color temperature in Kelvin (K). There may also be an option to measure an external source such as another calibrated display that you want to match.
Luminance: it’s useful to be able to specify a maximum luminance and confirm it via measurement, especially if you have multiple monitors and want to standardize your working conditions.
Black point: it’s also useful to be able to specify the luminance of a completely black pixel, particularly if you’re working on images for commercial print. Most LCD displays are capable of a contrast range (the ratio between brightest white and darkest black) well in excess of what’s achievable in print so if your display’s black is very dark, you might find it helps to set a black that’s above the minimum level.
Profile type: there may be some options on the profiling side, with a choice of matrix or LUT (lookup table)-type profiles. The former are simpler, but the latter are considered to be more accurate. Some older software – notably Photoshop CS2 and earlier – doesn’t support LUT-type profiles fully. Some high-end display calibration software will allow you to make both kinds of profile from the same set of measurement data.
You may also have a choice of making Type 2 or Type 4 ICC profiles; Mac OS X (10.4 Tiger and above) and Windows (Vista onwards) both support Type 4 profiles but Windows XP (up to SP2) and some older applications can only work with Type 2 profiles for displays.
Application-specific modes: avoid options to vary the color on your display via application-specific modes such as ‘photography’, ‘gaming’ or ‘video’. The point of calibration and profiling is to give you accurate color on screen all the time so you know exactly what you’re working with. Any color editing that’s then necessary should be done in your image editor, rather than by adjusting your display profile, which would affect how every image is displayed.
This article is based on Practical Colour Management for Photographers and Digital Image Makers, an e-book that’s full of detailed practical tips on how to ‘do’ color management on real computer displays to support high quality image editing. It includes tips on choosing and using colour-critical equipment and the optimum system software settings and working environment for reliable results.