[Openicc] ALL YOU NEED IS A PROFILE, THE MYTH... linearization / G7

[Jan-Peter Homann]

hello list,
I agree with edmund, that good linearization is the most important basis 
for good results in printing.
As in a former mail, i strongly recommend to look at G7-process from 
IDEAlliance / GRACoL as target values and method for linearization. This 
will lead to a gradation and gray balance which is very similar to SWOP 
TR001, GRACoL2006coated and ISOcoated_v2/FOGRA39 the worldwide most 
important standards for CMYK-data.

for sRGB-data standard settings, it would be possible to use a 
standard-conversion sRGB->SWOPTR001 or littlebit better 
sRGB->GRACoLcoated without the need for individual printer profiles

For the  CMYK-data standard-settings it would be possible to deliver a 
standard conversion e.g. SWOP->SWOP_GCR only for applying GCR and 
Inklimit without changing the color appearance.

Combined with tools for optimal (re)-linearization based on G7, we could 
handle the most important steps for predictable color in printing 
without the need of dozens of profiles for differnt papers. Tools for 
(re)-linearization should also include procedures for checking the 
actual linerization (by comparison to a printers sample or masuring with 
a i1 spectrophotometer)

ON TOP of (re)-linearized system we can talk about standard printer 
profiles for different types of paper and the possibility to integrate 
individual printer profiles.

Regards
Jan-Peter

edmund ronald wrote:
> I think I need to put out a new topic explaining why PROFILES COME LAST.
>
> Profiles allow softproofing on screen. They allow simulation. They
> allow gamut mapping. BUT THEY COME LAST.
>
> The inkjet industry has been exposing "visible" profiles because they
> allow the above (softproofing, simulation, gamut mapping) when used
> with Photoshop. However in practice, the profile will only get decent
> results if the press or inkjet driver are already pretty well tuned to
> put down the right amount of ink on paper.
>
> The inkjet native drivers do this, in a "secret" way. Which is why
> using third party papers or inks is complicated. No surprise here,
> inkjet manufacturers make their profit from paper and ink sales.
>
> What the inkjet guys and RIP resellers really guarantee in exchange of
> their excessive profits is perfect stability. A print run today and in
> one year with new inks, a new batch of paper,  and maybe with a
> different OS and maybe with a PC instead of a Mac, and maybe even a
> new printer of the same brand and model etc etc will usually still
> yield results that are usably close. This is why canned profiles are
> useful, why third party profiling makes sense, and why end-users don't
> need spectros.
>
> Before open-source people start to worry their heads about profiles
> they should first turn their attention to obtaing the same degree of
> cross-platform cross-application and time-invariant stability
> guaranteed by the native printer drivers.
>
> PROFILES COME LAST, folks, really..Just like Gutenprint is already
> pretty useful, Argyll is also very good; Lots of people own spectros,
> and they're getting cheaper. Profiles themselves are easy to make.
> Creyating the preconditions for a good profile is hard.
>
> 1. If your printer drivers have a block the shadows or have an
> insufficient gamut because of bad linearisation, color consultants
> will advise users to use native drivers because  it's very hard to
> compensate for bad linearisation.
>
> 2. If your system keeps varying its output each time you update then
> your end-users will get VERY unhappy and will ditch your apps presto.
>
> In summary: Profiles are the last link in the printing chain, and
> probably the most trivial step for well-equipped domain experts to
> achieve, even if this appears counter-intuitive to programmers.
>
> Edmund
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>
>   


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