Datacolor User to User Support Group.

On Mar 17, 2009, at 11:12 AM, PJS wrote:

>
> Here's a primer on rendering intents by IBM:
>

<snip>

It's things like this "primer" from IBM that gives people the
wrong idea about rendering intents. (what does IBM really know
about color printing...? :-)

Particularly what they say about "Saturation" and business
graphics. This is the same old tired line that people keep referring
to when talking about "not" using Saturation when making photographic
prints.

There is no "rule" that says that Saturation rendering intents
in printer profiles have to be "bad", or at least, unsuitable for
printing anything other than business graphics and charts.

Printer profiles contain data in each of their rendering intents
that the printer profile software and/or printer manufacturer
designs a certain way. There are general guidelines (not from IBM,
but in the ICC specification) which are suggestions about
what the different rendering intents in the profile should do,
but software that creates printer profiles is free to put whatever
it likes in any/all of the 3 "slots" in the profile that contain
the data.

It's really not useful to look at something written by IBM about this...
my guess would be that this is from a document that's at least 10 years
old.

I can categorically tell you that, contrary to what this IBM document
says, in-gamut colors are NOT adjusted to be more vivid in our profiles
when the Saturation intent is chosen, and there is no rule in the ICC
spec for printer profiles that says this should be happening, either.

In the past, manufacturer's printer profiles may have been doing that
with the Saturation intent (years ago), but in looking at more recent
profiles done with more modern printer profiling software (other  
packages,
not ours), I don't see the same kind of hugely objectionable color  
shifts in
the Saturation intent that older profiles would have produced.

***

Looking at the document that you're referencing... this is for a  
specific
family of IBM printers. Not inkjets...! And not with any other profiles
other than what IBM supplies for/with them. These laser printers will
also be CMYK profiled devices (not RGB) and these are going to be
limited gamut printers that aren't going to be useful for photographic
printing.

This is a document that is SPECIFICALLY about the "InfoPrint 4100 family
of printers" which are "...laser, electrophotographic print technology".

What they're saying is, I'm sure, correct and applicable for these IBM
printers which are not only a different printing technology, but which
have profiles created for them that will presumably match the  
descriptions
for rendering intents in the document.

None of this has anything to do with color inkjet printing using RGB
printer profiles on wider gamut inkjets.



David Miller
Senior Software Developer, Digital Color Solutions
Datacolor