Hidden Secrets of Color Profiles

If you're even half-way serious about taking pictures, editing them, and then showing them on the web or printing them out, you need to know about color management. It seems to be pretty difficult stuff, in part because hardly anybody does it right. Once you think you know what's going on, nothing looks right because the software you're using screws up your best intentions. Here's an overview of what you need to know, and why it may not be you that's doing something wrong.

Computer represent colors by numbers. The number 123456 is a color. But exactly what color that number represents depends on the color space being used. One simple color space is RGB, in which different parts of the number represent a mix of red, green, and blue, respectively. Greatly simplifying (and ignoring number bases), in the previous example 12 might represent how much red, 34 might represent how much green, and 56 might represent how much blue. Many computers use RGB as sort of a common language when shuffling image around, but different companies such as Adobe and organizations such as the International Color Consortium (ICC) have created different color spaces that map to a great range of colors in some areas (perhaps more skintone colors while sacrificing shades of gray).

A color profile provides information on translating one of these other color spaces into RGB. If you use Lightroom to edit a RAW file from your new DSLR camera, you might use one of Adobe's color spaces. When you then spit out a JPEG, your editing software might embed a reference (or the actual profile) inside the JPEG so that the computer will know how to convert the color space to RGB later on. (I am no expert in this area; this explanation on the JPEG side likely has errors, but this is the gist of it.) But the catch is that your imaging software must know how to use the embedded color profile, or the picture you view won't look like the picture you edited. IrfanView, one of the most popular image viewers available, claims to handle embedded color profiles if you turn on that option.

But there's still one more twist. Your monitor probably doesn't show colors correctly. That big flatscreen may have been a bargain, but it also may not have been built for professional color editing. When the numbers inside your JPEG say "show a medium red", your monitor may show a dark red. In fact, it may (like the popular Dell 2407WFP-HC I'm using now) show everything with a red tint. But there is a solution: a color profile for your monitor. A monitor profile will tell how RGB colors map to what your monitor displays. If the JPEG indicates that a medium red should be shown, the monitor profile will indicate that this should be converted to a light red to conteract the monitor's red tint. You can use a calibration system such as Spyder to create your own custom profile that's really accurate, but operating system may in fact have already installed a default color profile for your particular monitor model. (Check the display properties in Microsoft Windows.)

So you've edited your RAW file in Lightroom, embedded a color profile, and made sure a profile is associated with your monitor. You load the image in Firefox 3 on the Dell 2407WFP-HC, and it looks all red! Why? Because Firefox 3 by default is ignoring the color profiles. You'll need to type about:config in the address bar, and set gfx.color_management.enabled to true. Word is that Firefox 3.5 will turn on color management automatically.

But you want to be able to view a slideshow of all your new pictures, so you load up IrfanView, which claims color profile support, and your pictures are once again tinged with a hideous red. It turns out that IrfanView only addresses half of the color profile issue. It loads any color profile information embedded in the JPEG so that the colors can be converted to RGB (often at a significant performance hit), but then it ignores the monitor profile and sends the RGB values straight to the monitor where they are at the mercy of the monitory's not-so-great rendering.

You need an image viewer that not only reads any color profile information embedded in the JPEG but that also pays attention to the monitor profile, such as Firefox 3 does after you configure it to do so. Unfortunately most free image viewers ignore the monitor profile, but I've found one slick piece of software that does the trick: FastPictureViewer. You'll need to go into the options and turn on color profile support and, unlike Firefox (which can pick up the color profile your OS has associated with the monitor), actually specify which monitor profile to use. Then you'll have a slick image viewer that shows your images like they looked when you edited them. Good-bye, Irfanview.