When you create a profile in Profile Prism, it automatically creates two profile look-up-tables inside the profile (ICM file): one for Perceptual and one for Relative Colorimetric.  If you choose Perceptual, it uses the perceptual table in the profile.  If you use RC, it uses the RC table.  They are simply two different mappings that map the colors completely differently for different purposes.  It's sort of like having two different profiles in one ICM.  Actually, exactly like having two versions of the profile.

If you already use RC, you're good to go: that's typically the recommended setting for printer profiles.  Only reason I pointed it out is if you happen to use Perceptual, (some) colors might be a bit muted as the profile tries to expand the gamut coverage of your printer.  Perceptual intent does that by toning down saturation a bit (in needed areas) to "fake" the appearance of the printer being able to resolve colors beyond what it really can.  Why would you even want to do that?  Only in special cases where you might want to show a color gradient in a logo or something that might have very bright out-of-gamut colors and it's more important that the gradient show than match the exact color.  In a case like that, RC might clip the colors and give a rough gradient.  Perceptual would tone them down a bit (typically desaturate) so that you at least get a smooth gradient as opposed to one that might look blown out.

Oh and one other "nasty" little tidbit about ICC profiles is that they are not "smart".  They can't read the gamut of the input image and only scale (fade) colors for perceptual intent for only the colors in the original image that need it.  ICC profiling is done with no consideration of image content... which means with perceptual intent, the gamuts are "smashed" the same amount for every image, even if you only print an image that has very subtle colors: those will look faded too with perceptual intent.

It's 10pm here so I'm done for the night.  Been at it 14 hours today.  

Mike

Thanks very much Fred.

In Mike's comparison the manufacturers profile is totally believable!

As you will be aware, Mike described Perceptual v Relative Colourmetric intents before he went to bed! I'm familiar with them and I always use RC when printing.

Maybe I have misunderstood some of the comments relating to intents. Are you actually selecting RC somewhere in Profile Prism when you are setting up and generating a profile? If so, where are selecting it?

I'm working on the 8.4 profiles now so if you can reply soonest that would be appreciated.

Thanks again.

Peter
 

Thanks Fred.

That's what i thought but some of the comments made me think otherwise and that i was missing something relating to PP.

Yes, I'm familiar with the Intent settings in QIU. The settings in your screen captures are as I've been using for "yonks".

Now to print my test image with 8.4 .....

Regards

Peter