[argyllcms] Re: [argyllcms] Re: Printtarg dithering for TIFF output request

  • From: Nikolay Pokhilchenko <nikolay_po@xxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sat, 07 Apr 2012 15:26:14 +0400

Graeme Gill wrote:

Nikolay Pokhilchenko wrote:
> 1) generating the target data with preliminary (from similar device) 
> ICC-profile; 2) generating
> 16-bit TIFF target images; 3) changing the "color depth" of images from 
> 16-bit to 8-bit in Adobe
> Photoshop Elements (the dithering is applying in Photoshop by default); 4) 
> saving 8 bit per
> channel targets.

Hi Nikolay,
 such a thing is certainly possible, and I have some well developed stochastic 
pattern dither code that could be applied to the task, but I guess I'm a little 
by the work flow :- normally in color management you strive to keep the 
profiling and
final used workflows as close as possible, so the question is why the profiling 
is 8 bit, while the printing workflow is 8 bit dithered ? What is doing the 
for the normal printing workflow ? Why can't the 16 bit test chart be printed 
that workflow ?

Well, it's a good question. I didn't want to explain to the end users why I ask 
them to print 16-bit targets when they prints 8-bit images in general. I want 
building a good profiles with the user's habitual image bit-depth. The end user 
can disable dithering by mistake. And if I send him 16-bit target files, it 
would be impossible to characterize ink mixtures between quantization levels. 
On the contrary, while printing at high printer resolutions with dithering, the 
intermittent ink quantities can be characterized easily without 16-bit test 
charts and without dithering at the user side.
It will be simpler to ask the user to enable dithering if the problem will 
arise after profiling nor explain them how to print 16-bit targets correctly 
and where to check the dithering settings in his application before target 
So, I'm preferring to keep the dithering under my control, not at the user 
side. It saves the time both mine and the client.

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  • » [argyllcms] Re: [argyllcms] Re: Printtarg dithering for TIFF output request - Nikolay Pokhilchenko