[Gimp-developer] digested: printing presses, cmyk, tiff + pdf...

[Andrew A. Gill]

On Thu, 26 Mar 2009, Robert Krawitz wrote:
>
> I think the case of "text black" is a partial, qualified exception --
> but it's arguable that it has any bearing on RGB vs. CMYK.  It really
> means "the darkest, sharpest black that can be produced" regardless of
> rendering device.  It could just as well be represented as RGB+K, or
> simply as a separate layer.  I'd argue that it's actually a creative
> choice, though.

It doesn't necessarily mean the darkest, but it does mean the 
sharpest.  And you're right that it could essentially be 
represented as RGB+K.

> Perhaps prepress tasks would better be implemented as a plugin (or set
> of plugins)?  It's hard for me to see how trapping (for example) would
> make any sense at all as part of the core, but as a plugin it would
> make perfect sense.  I know Adobe at least used to sell a product
> called TrapWise whose purpose in life was to do nothing but trapping.

Automatic trapping is actually not a bad idea for a plugin.  You 
could have things like trap along path or edge detection trapping 
(which I used as an example of something that would be 
prohibitively expensive in an interactive mode, but in one-time 
mode wouldn't be an issue).

It would, in general, be a very dumb plugin, but some simple jobs 
don't need intelligent algorithms to determine that we don't need 
the red eye effect trapped but that the magenta hankerchief in 
the suit pocket does need to be, just to trap the edge of the 
photo that got torn and you're outlining with a black border.

> I don't know if it had a Photoshop plugin component or not.

TrapWise began with Aldus and was subsequently acquired by Adobe. 
TrapWise is now owned by Kodak, who describe it thus[*]:

``TRAPWISE's streamlined workflow, intelligent trapping engine 
and flexible productivity tools combine to give you precision 
trapping whenever and wherever you need it.''

As I suggested in the other message, sophisticated automated
trapping is probably going to be more difficult than simply 
implementing CMYK editing, since you're going to have to 
implement many of the same features--CMYK editing (batch, not 
interactive, granted), colorspace conversion, alterations to the 
XCF file format--plus a bunch of other features like advanced 
edge detection and an evaluation system to determine what needs 
to be trapped and what does not.

There's a reason why TrapWise was pulling in $7000 a copy in 2001 
when CS2 Premium was only $1200.


[*] <http://graphics1.kodak.com/us/product/workflow_data_storage/production_planning/trapwise/default.htm>

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