Digital photography has presented all photographers with a dilemma that will confront them sooner or later, and it is to do with handling colour, or better known as colour management. Colour management is the means by which colour can be kept track of, and controlled from capture, monitoring, and through to final printing. Without a system in place to control how colour is handled, photographers will be fighting a losing battle to maintain colour consistency and predictability in their images. Without a colour management system in place, invariably the images will always look different in print than they do on one’s monitor, which leads to frustration.
Colour management is primarily based upon having images a set colour space to work within, and profiles for all hardware that will process images. In other words, the images from the camera need to have colour profiles, the monitor that displays the images needs to be profiled, and the printer that finally prints the images also needs to be profiled. The reason is simple, each type of hardware, and indeed each brand of hardware, all treat colour differently, and without some means of keeping track, and then compensating for these differences, colour has no chance of retaining any fidelity to what is expected.
Attaching a set colour space to an image is the starting point in colour management. Probably the most commonly used colour space is Adobe RGB 1998. It has quite a large colour gamut, which in most cases exceeds the capabilities of monitors and printers, although the gap has been steadily closing, and some top end monitors and printers can actually exceed the Adobe RGB colour space in certain colours. Colour gamut is essentially the range of possible colours within a certain spectrum. Once a colour space is attached to an image, it sets the range of possible colours that that particular image can possibly display. It also tells any program that utilizes colour management, how that image should be displayed, as it has now has a known and measurable set of colours used by that image.
Profiles are needed to control how hardware handles colour, and as stated above, each device has its own technological limitations that differ from each device, and from brand to brand. Cameras can handle a different range of colour, or gamut, to what monitors can handle, and so do printers and digital projection displays. So it is therefore impossible to have a common profile for each device, as they are all different. It gets even worse, even printing papers vary considerably in the way they can display colour, and each individual paper requires a separate profile. These profiles are generated by measuring devices such as colorimeters or spectrophotometers, which measure the limitations of the device, and then a profile is created that tries to compensate and correct the output of that device to a set standard.
By using an established colour space for images, and correctly calibrated monitors and printers, one then has a common starting point from which to control his or her images in terms of colour. It allows for a controlled and predictable exchange of images to third parties, whereby one can reasonably confident that his or her images will look the same on other systems that are also properly colour managed. However, colour fidelity is still very much at the mercy of the quality of the devices used. If cheap low gamut devices are used to display or print images, then the colour gamut will suffer, and as a result the images will not look as they should.
Colour management is a very involved subject, and the above is just a brief outline of what it is all about.