Datacolor User to User Support Group.

Rendering intents just determine how the system handles out-of-gamut  
colors in the printing process. (If the gamut of your photo includes  
colors that your printer can't reproduce... and it almost always  
does....) In other words, the rendering intent just tells your printer  
how to "fake it" in the most pleasing way by explaining to the printer  
that "Yes, this red is the best substitute for the out-of-gamut red in  
your photo".

It's applied after the ICC profile is created because the profile  
tells the system how to optimize the printer's gamut for accuracy and  
the rendering intent tells the system what to do when colors exist in  
the image that even the most accurate printer gamut isn't capable of  
reproducing with that printer.

There's nothing sacred about one rendering intent vs. another - and  
the differences tend toward the subtle.  If you have Spyder3 Print,  
the soft proofing checkbox gives you a way to compare them (sort of -  
they're still limited by monitor gamut) Conventional wisdom is that  
relative colorimetric tends to reproduce the relationship of colors  
more pleasingly, while perceptual tends to reproduce range of  
luminance more pleasingly. Don't know about the advantage of  
Saturation, but it does look good with the S3 test images on my  
printer. Absolute just chops the out of gamut colors, and generally  
looks the worst.

If you don't mind blowing 4 sheets of paper and some ink, just print  
the S3 Print test image page with each intent and look at the  
differences. Decide for yourself what you like.
stsk


On Mar 17, 2009, at 6:03 AM, Myron Gochnauer wrote:

>> Profile creation is not intent based; all the intents are created.  
>> Its
>> when you go to use the profile that intent selection occurs.
>
>> So there is no issue about what intent is selected at the time you
>> print a target, measure the target, or build the profile, only at the
>> point in time when you use the profile to print an image.
>
> If this information is not highlighted in the documentation, it  
> should be. It may be obvious from the actual profiling process, but  
> it is easily forgotten...  all I could remember is that CDavid said  
> at one point that "Saturation" intent was "recommended", so I have  
> used that exclusively (unless the printing program didn't offer it).
>
> I think I simply do not understand with these "Intents" do. I've  
> been using Saturation Intent for ordinary scenic photography and  
> portraits, which call for subtle colors and transitions, unlike  
> "charts and graphs" that Adobe says Saturation is good for.  And my  
> results are, it seems, very good.
>
> So when does the "Intent" actually kick in? When would it make a  
> difference? When the printing gamut does not match the gamut of the  
> image, and colors must be adjusted to fit?
>
> My male red/green weakness makes me suspicious of my color  
> judgments, so it's difficult for me to just try these things and  
> "see".
>
>> ... we suggest you try the Saturation intent, as it may be just what
>> you want.
>
> Why wouldn't this be something you would suggest only if "Perceptual  
> Intent" --- whose description corresponds with what most  
> photographers are looking for --- is problem! atic in some  
> specifiable way?
>
> Myron
>
>
>