[NTG-context] colorizing pictures

Henning Hraban Ramm texml at fiee.net
Tue Mar 19 18:54:08 CET 2019


Am 2019-03-19 um 16:34 schrieb Hans Hagen <j.hagen at xs4all.nl>:

> On 3/19/2019 4:23 PM, Henning Hraban Ramm wrote:
>> Am 2019-03-19 um 13:23 schrieb Hans Hagen <j.hagen at xs4all.nl>:
>>> On 3/18/2019 7:45 PM, Henning Hraban Ramm wrote:
>>> from one of the manuals ...
>>> 
>>> \starttext
>>> 
>>> \definecolor [my-blue]   [c=1,m=.38,y=0,k=.64] % pms 2965 uncoated m
>>> \definecolor [my-yellow] [c=0,m=.28,y=1,k=.06] % pms  124 uncoated m
>>> 
>>> \definespotcolor [my-blue-100]   [my-blue]   [p=1]
>>> \definespotcolor [my-yellow-100] [my-yellow] [p=1]
>>> \definespotcolor [my-blue-50]    [my-blue]   [p=.5]
>>> \definespotcolor [my-yellow-50]  [my-yellow] [p=.5]
>>> 
>>> \definemultitonecolor [my-mix] [my-blue=.12,my-yellow=.28] [c=.1,m=.1,y=.3,k=.1]
>> So it works only with toned or multitone colors and only with _some_ greyscale pictures, not with bitmaps and also not with my greyscale dodo.
> 
> It uses an indexed (256 so one byte) image ... coloring a cow is no option anyway as there the pdf object is an independent thing (i could probably inject color directives if needed but that could then interfere with the way such a pdf stream is set up.

I didn’t expect PDF to work (I remember colored cows, but those were probably MP), and I must analyze why your greyscale PNG works and not mine.

>> I can also only use one version my-blue – if I use my-blue-100, then my-blue-50 stays grey, and if I only use my-blue-50, it’s the same tone as 100.
>> Something’s very fishy.
> Could be but it's actually more a gimmick as we can't really mess to much with the internals of images (they can have masks, palettes, etc etc).

Understood. But colorizing grey pictures is a nice feature that I’m used to use in InDesign (and in QuarkXPress earlier).

> Later this year there might be other tricks on our sleeves but I'm not going to touch the code now.

I’m looking forward to those.

Since I’m working at my ConTeXt book again, I’m researching which parameters and features actually work and how. This looks like a case that I won’t include in the book but only document in the wiki.

Greetlings, Hraban
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