But wait, theres more! While each of your devices possess their own color characteristics and these arent similar to each other, the color characteristics definitely arent equal to your chosen Color Space. Every step of the way whether displaying an image on the monitor or printer, some sort of conversion has to be done. Notice I havent mentioned how your image is directly displayed using your chosen Color Space. Remember, Color Space is nothing but a reference system, a set of standards, like the English or Metric system. You dont actually see your Color Space. Every step where you see an image displayedwhether on a monitor or as a print--some sort of conversion process was accomplished to get the color as defined in the reference Color Space to display on your monitor or printer. I like to look at the purpose of your Color Space as the backbone of your digital imaging process. It establishes the "truth" of your colors. Displaying your image on monitors and printers are nothing but well defined departures from that backbone and "truth".

Making It All Work

Enough mumbo jumbo on theory, how does this work with your computer? First, pick a Color Space. I like using Adobe 98 only because its widely accepted by so many people. As a general rule limiting the total number of color conversions an image file goes through is a good thing so anything you can do to match someone elses workflow will reduce the overall need to convert colors with some sort of translator. Having your images defined by Adobe 98 is a great way of ensuring you and everyone else is talking in terms of the same reference system.

When color characteristics differences from one device to another are thoroughly defined, theoretically you have path to travel from one device to another. In theory, if you know the precise difference between the Color Spaces, you can map the color numbers of your image from one space to the other with great reliability. But, theres a problem. No two Color Spaces are the same. Something has to give when moving all the colors from one space to the other. So, theres a real danger of degrading your image file by converting the image poorly. Fortunately there are four well-used algorithms that can make the conversion for you.

The following are the four typical conversion routines, rendering intents, available in Photoshop for converting colors between reference systems. These are chosen by you and will be used whenever colors are adjusted from one system to another.

• Relative Colormetric: Tends to map colors relatively from one Color Space to the other, preserving color relationship with the medias White Point. This is recommended when most colors are within the range of the new Color Space.
• Perceptual: Requests a visually pleasing rendering. Tries to maintain relationship between colors during the conversion. This rendering intent is recommended when the new Color Space has a smaller gamut than the old.
• Absolute Colormetric: Maps color directly from one Color Space to the other. Not normally used for photographs and more often used for logos. Truncating colors is a distinct problem with this rendering intent.
• Saturation: Tends to a highly saturated rendering at the risk of losing color accuracy. Used in business presentation situations where color accuracy is less important.

You personally arent making the conversion, your computer is. In fact, moving from one color space to another is a highly complicated math challenge thankfully done in the background while youre happily working your computer.
One last thing on color conversions, these rendering intents will be extensively used when we discuss printing. So, save this info because well be using it later.

Now for the bad news, color calibration is not without effort on our end. There are things to do, the first of which is defining the Color Space to be your truth or reference system by which everything else is measured. So, which Color Space?

I use Adobe 98 since its an industry standard for the imagery world. As I noted before, its especially well suited for the four color printing process and it has a good sized color gamut meaning youll have more colors to work with in your digital darkroommore is better in this case. Once choosing a Color Space, make sure you image-editing programs color settings are defined appropriately to deal with your chosen Color Space. In my case, go to the preferences of Adobe Photoshop and select color settings. Change the Work Space menu for RGB to Adobe 98. To make things as painless as possible and to avoid possible unintentional conversions, you can configure Adobe Photoshop to warn you when working with images that arent youre chosen Color Space. In this case, I set my color management profiles to Preserve Embedded Profiles and check all the warnings. Under these conditions I always have to give permission before any images are converted from my chosen Color Space to another.