Thanks sincerely for your suggestions. But I'm pretty sure that the issue
is not the RIP settings. If it were, then both profiling packages would
have the same or similar problems. But they don't. Also, if it were the
RIP settings, then the changes to those settings would have an effect on the
problem. As I mentioned in my original posting, I have tried numerous ink
limits in both the individual channels and total ink. I've even tried
numerous papers. I even checked with the manufacturer of the RIP to make
sure I am setting it properly (I am). While these ink limit changes
affected the minimum L* (of course), they did not affect the three problems
I reported. Finally, if it were a problem with my RIP settings, then others
would not have responded (off list) with similar results from other RIPs.
So, the three problems/observations remain:
Monaco reverses (slightly) after reaching dMax (Gretag does not)
Gretag consistently produces slightly lower dMax than Monaco
Gretag consistently produces higher chroma error in the neutrals
My posting had two purposes: to confirm that others were/are seeing this;
and to solicit thoughts from people on this list who have knowledge of how
the neutrals are calculated/analyzed in an effort to understand why this
might be happening.
As I mentioned above, others have confirmed the same problem that I've seen.
But I'm still interested in understanding how these problems could exist.
In other words, I can understand how one software package might extrapolate
or interpolate gamut boundaries differently or perform gamut mapping
differently. After all, that's the "secret sauce" for the profile software
guys, right? But what I'm wondering is how two different packages,
presented with the same data, would produce different neutrals for the
RelCol intent. It seems to me that neutrals for RelCol should be
consistent. Is it possible that, even in the RelCol intent, the software
maker has discretion such that the profile calculation can be weighted more
towards some other factor(s) that would give up neutrals accuracy?
> -----Original Message-----
> From: Troy Buccini [mailto:tbuccini@yaho...]
> Sent: Thursday, January 05, 2006 8:08 PM
> To: Michael Fox Photography News Account
> Cc: 'Dan Reid'; 'colorsync'
> Subject: Re: Monaco vs. Gretag Neutrals Analysis
> Hi Michael,
> I have tried Dan's method for ink limiting and can assure you it is
> the best way to get lower L*'s, cleaner neutrals, and over better
> color matches. 360 seems really high for an ink limit on a Matte
> paper. I am not sure what RIP you are using, but my experience for
> getting the lowest L* without sacrificing gamut is around 330 and
> lower for a microporous paper. matte papers will always take less
> ink. Up your resolutions and your TIL will need even lower numbers.
> Actually another thing to look at is to see if your 2-3 color ink
> limits are too high. Again each RIP does this slightly different, but
> if you are using Epson UC inks, they are somewhat predictable. Yellow
> is always way to strong and Magenta is usually pegged because it is
> not really magenta it is blueish until it hits maximum limit.
> Monaco and PM are were not built specifically for this ink set.
> Therefore, proper inklimits and custom charts will help tremendously.
> You might even be somewhat happy with PM's inkjet 260 default. Now
> with that said I wish the manufacturers would publish best practices
> for these printers as they are somewhat of the defacto for Proofing
> and Fine Art.
> On Jan 5, 2006, at 12:12 PM, Michael Fox Photography News Account wrote:
> > Hmmm.
> > The profiling software should ignore color patches that have a
> > higher total
> > ink build than what is called for in the total ink user input field
> > so it
> > shouldn't matter how much higher the RIP total ink limit is set.
> > Right?
> > Michael
> > ________________________________________
> > From: Dan Reid [mailto:photolist@rpim...]
> > Well the profiling app is telling you have too much ink which is
> > why it's
> > building it at much less than your RIP ink limit. You may look at
> > reducing
> > your ink limit at the RIP and you might find the shadow reversals
> > (too much
> > ink) go away. 360% is a lot of ink on paper so you must either A)
> > have a
> > super coated stock and/or B) not using a high printer resolution
> > which would
> > put down twice as much ink.
> > I determine the sweet spot for RIP ink limit by evaluating
> > different ink
> > limit settings in ColorShop X. Look for the darkest L* and that's
> > where you
> > should set your ink limit. Use the same ink limit setting in
> > reducing your
> > profiling chart ink coverage.
> > - Dan
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