Re: [Gimp-developer] Soft proofing and the GIMP Display Filters and Color Management settings

[Gez <listas ohweb com ar>]

El mar, 11-03-2014 a las 07:16 -0400, Elle Stone escribió:

> I don't know anything about CMYK printing and I've never used the CM+ 
> plugin, so please bear with me while I ask a couple of questions:
>
> Putting *editing* CMYK channels to one side, is it useful to modifythe 
> RGB channels while soft proofing to a CMYK profile (or even n-channel 
> profile whether color or black and white)? I thought that was what the 
> CM+ plugin made possible? Is this an example of what Gez calls "late 
> binding"?

Not exactly, but related.
There are three possible workflows for print:
Early binding: All the assets are converted to CMYK and editing is done
in CMYK. The files you send to the print shop are CMYK.
Late Binding: Everything is worked in RGB. The print shop converts to
CMYK.
Intermediate Binding: Creative work is done in RGB, the files are
converted to CMYK prior sending them to the print shop.

GIMP can't edit CMYK directly, but it can serve to the other two
possible workflows.
soft proofing to a CMYK profile is useful because you can work in RGB
with all the freedom it allows, but at the same time you can "preview"
how the target gamut and rendering intent will affect your image. I
think this is specially useful when using colorimetric intents, where
all the out-of-gamut values get clamped.

CM+ allowed that. Iirc, it did more or less the same than the current
color proof filter with some extra goodies (individual CMYK channels
preview, black ink/paper white simulation, etc.)

Check this video from 1:40
https://www.youtube.com/watch?v=Q99MeymK7wA&feature=youtu.be&hd=1
(if you can endure the disturbing music, it shows the filter in action).

> Having the title/status bar(s) show which display filters are active 
> would be very useful, especially given that if you close the display 
> filter window, any activated filters (or deactivated, in the case of the 
> Color Management filter) are still applied to the image.

That would be an interesting addition, but I wonder if the current model
of having multiple "working profiles" can't be replaced by something
more useful.
This is probably off-topic, but having to worry about the file profile,
a working profile, a print preview profile and a print profile in the
preferences as global settings seems messy and inefficient. And in GIMP
2.9 it probably doesn't make so much sense as it used to.
> From a user point of view having all the imported stuff converted
automatically to a high quality internal model (high bit depth linear
scRGB?) and having per-image output/proof settings seems more
straightforward and less error prone than the current mixture of
profiles.
It may or may not be a problem for keeping legacy compatibility, but I
can imagine how simplified the UI and common workflows would be (no
bit-depth "modes", no assign/convert to profile, no profile-mismatch
warnings, simplified CM preferences, etc).

Gez.