Color Management, Calibration and Color Spaces Oh My!

One of the more complicated issues that come up when dealing with digital photography is color management. Color management is all about trying to get the colors that you want, to display properly on a given device, such as a print made on a desktop printer, or a print you get back from the photo lab, or even just on your monitor. By "devices" we mean anything that can record, display or print an image... so cameras, scanners, printers, monitors, and even papers and inks all need to be "managed" so that you get consistent color. You might find that color to not be what you want it to be, but the first step is to at least be able to consistently get the same color.

Monitor Calibration, Color Spaces and Profiles

These three words are the main building blocks of color management, and basically all refer to the same thing - a color space. A color space is basically the amount of color that is contained in something... all devices are capable of different colors ie - none of them are the same really... monitors, cameras, printers... they don't all reproduce colors in the same way. So you need something to be able to refer to the colors they can produce, and that is basically a color space. So a cell phone with a little camera in it can produce some colors, but probably not as much as the latest pro digital camera. Same with printers - a cheap color printer won't reproduce color as well as a $200,000 laser printer in a photo lab. But knowing which device can produce which colors will allow you to get consistent color.

Monitor Calibration: Every monitor displays color different - even 2 monitors from the same manufacturer will probably show a slight difference... and then on top of that, monitors usually have color, brightness and contrast controls that you can play with... well, given all that, how do you know what is neutral? what is correct, and what is being biased by the controls being too bright, or the monitor not displaying colors correctly? Unless you calibrate it you won't know. Calibration (we'll stick with hardware calibration as that is the only way to go really) refers to using a device that sticks to the front of the monitor and reads the light coming through it - the little device looks sort of like a hockey puck sometimes, so people sometimes refer to it as a "puck". The software that comes with the puck will display different colors on the monitor, and the the puck will read them. The software will then compare what the puck read on the monitor compared to what the software displayed, and figure out the difference, or calibrate it. Then the software can say, well, I sent the monitor black, but it really read it as dark gray. Or the monitor was supposed to display red, but it was really magenta. Now the software will attempt to guide you through adjusting the color, brightness and contrast of the monitor to get as close to neutral as possible. What ever cannot be accomplished with the monitor controls will be built into a profile, which your graphics card will use to try and display colors more accurately.

Color Spaces: A "color space" refers to any set of colors that a device can display or record... so in effect, every device has a color space, and most of them are unique. That said, when you hear "color space" most of the time people are talking about defined color spaces - there are several well known, well defined color spaces that are used as general default color spaces - in other words we convert whatever came out of the camera or scanner into one of these default color spaces so that we can use them across a range of devices and keep things simple. This way I can send a file to a friend and he can open it on his computer and not need to worry about whatever unique color space my camera happens to be capable of. The two most popular color spaces are Adobe 98 and sRGB. Must pro level cameras will allow you to set the color space the camera will shoot in to either Adobe 98 or sRGB. There is quite a large difference in the two, and selecting which one you use can be fairly important. For more on this, see the article above titled "Color Spaces - sRGB and Adobe 98".

Profiles: A color profile is a complex description (using all kinds of voodoo magic) of a color space - this profile is used to tell devices how to interpret the colors. So if we were to send a digital file to a friend and say - here is that image, the color space it is in is xyzzzyzx, your friend won't be able to view it properly unless he has the profile for xyzzzyzx - that is what will allow his monitor or printer to display it properly. This is also why we use Adobe 98 and sRGB so much - convert the image to one of those, and then you can share it with pretty much anyone as those two color spaces are pretty much available in every image editing program. Profiles can be very important when printing something - generally you will want the color profile for the printer and paper combination you will be using. If you are sending images to a lab, you probably should stick with sRGB unless they tell you differently. Most traditional chemical based printers are sRGB printers. Building a printer profile usually is done by printing out a target print spefied by the profile software, and then reading that print with a device that measures the colors - very much like calibrating a monitor. Then the software compares the colors read from the print to what were in the target file, and builds a profile based on how the two compare. This can get pretty complicated though, and for the most part you will be ok sticking with one of the default color spaces - we prefer sRGB (again, see the article above - "Color Spaces - sRGB and Adobe 98").