"Convert to Profile" questions

[robert goldstein]

When converting from Adobe RGB (1998) to sRGB for web or printer output, what settings

are best in any given situation. "Relative colorimetric" is the CS default for Intent, but I

have seen recommendations for perceptual as well. And what about "black point

compensation?" Does it make a difference if one is working with a color image or a color

image converted to B&W with channel mixer?

 

Thanks,

 

Rob

[gary m]

The following is from something I found awhile back and saved on my computer. The last paragraph may answer some of your questions. The author is Jack Flesher.

 

"Perceptual compresses the colors in the wider source space to match the smaller gamut of the target (print or viewing) space. This is accomplished by altering the out-of-gamut colors and in-gamut colors so they appear similar when brought into the target space. The entire spectrum of original colors gets uniformly compressed in a way that maintains the overall relationship between the colors. By keeping the relationship between the colors the same, the overall appearance of the image remains the same. The downside is that we have little control as to how this compression is performed, and many of our in-gamut colors can get significantly altered form their original true color.

 

Relative colorimetric is similar to absolute colorimetric, but it applies some compression to the out-of-gamut colors to give them prominence in the target image. It differs form perceptual in that it does not compress all the colors equally, but rather applies higher compression at the outer limits of the colors to squeeze them all into the target space. At the same time it does not alter the main body of colors that can map directly into the target space any more than necessary to create smooth tonal transitions. RC also scales the white point of the source image to match the white point of the target space, giving the source space and target space a common color point for us to ?relate? to. This has the effect of making all of the colors appear the same hue relative to white even though they are not actually the exact same colors.

 

Generally speaking, in digital imaging for print output we will usually want to use either Perceptual or Relative Colorimetric intents when rendering our images. RC is best when only a small portion of colors from the source space will get clipped as the slight compression to the out-of-gamut colors is acceptable and the main body of colors is kept relatively intact. Perceptual is going to be the better choice when a large portion of colors from the source space are going to get clipped, as more compression is required to ?fit? all of the colors in the target space and still maintain smooth tonal gradations."

[paul_sokal___dallas__tx]

Rob,

 

It's really a matter of which looks better to you rather than right or wrong. I'd recommend you soft-proof you pic and see which you prefer.

[emre]

<a href="http://www.creativepro.com/story/feature/12641.html">Out of Gamut: Realizing Good Intentions with Rendering Intents</a> by Bruce Fraser.

[jespdj]

Look in the help function of Photoshop. It gives an explanation of the different rendering intents.

 

And also, just experiment and find out for yourself which one works best for you!

[andrew_rodney1]

working space profiles like sRGB, Adobe RGB (1998) etc are simple matrix based profiles and

only have one table for a rendering intent (Colorimetric). So you always get that RelCol (or if

you want but I don?t recommend it, Absolute Colorimetic which is from the same table). You

can?t get a Perceptual intent from a matrix profile but you can specify it in Photoshop.