Practical Color Management: Eddie Tapp on Digital Photography

2.4. Rendering Intents

As you've learned, different devices have different size gamuts. When you convert from one color space to another, the colors and tones need to be changed to fit into the new color space. The rendering intent is the strategy for resolving the differences in color space.

Rendering intents determine how the color of one device converts to another device. Depending on the color and tonality in the two different color spaces, the differences can range from minimal to fairly dramatic. When converting from one space, such as RGB, to another, such as CMYK, we go though the PCS (discussed in "PCS Source and Destination," earlier in this chapter). There are four different rendering intents that ICC profiles may have for resolving color differences: perceptual, saturation, relative colorimetric, and absolute colorimetric.

The images here illustrate the differences among the four different rendering intents. The effects of the different intents have been exaggerated so that they are easier to distinguish visually. Even with the exaggerated colors, it is still sometimes difficult to see the subtle differences.

Original image

Perceptual

This intent (sometimes referred to as photographic) tries to preserve the overall color appearance by changing the colors of the source image to fit into the destination space. It sacrifices accuracy to produce a more visually pleasing image. This intent is very useful when the source has a wide gamut and the destination has a small gamut.

Saturation

This intent tries to produce the most vibrant color by pushing the color of the source image out as far into the destination space as possible. It is not used much by photographers but is often used for business graphics to achieve bold color in presentations.

Relative colorimetric

This intent is used when color accuracy is the most important concern and is the default rendering intent in the more recent versions of Photoshop. It works very well when the source and destination profiles have similar gamuts. If the gamuts of two devices are too different from one another, the more saturated color may be clipped or minimized.

Absolute colorimetric

This intent is usually used for proofing when trying to simulate one device on another. It is similar to relative colorimetric, except all the color adjustments are based on the white point. Unlike relative colorimetric, absolute colorimetric shows the white of the source profile. In some cases, this intent can create an undesirable color cast if used as a default.

Perceptual

Saturation

Relative colorimetric

Absolute colorimetric