# [NTG-context] Rendering differences between PDF viewers

Peter Rolf indiego at gmx.net
Wed Apr 25 18:08:47 CEST 2012

Am 24.04.2012 15:37, schrieb Peter Rolf:
> Am 24.04.2012 14:42, schrieb Hans Hagen:
>> On 20-4-2012 09:50, Peter Rolf wrote:
>>> Am 19.04.2012 20:25, schrieb Hans Hagen:
>>>> On 18-4-2012 13:12, Peter Rolf wrote:
>>>>
>>>>> I understand that there is no easy or general solution for this.
>>>>> But on the other hand is PNG currently the only way to use transparent
>>>>> bitmaps in TeX. The usage of transparent PNG is quite common, so
>>>>> this is
>>>>> a general problem that should be solved.
>>>>>
>>>>> I like your idea of automatically adding such groups, if the user
>>>>> declares the color space beforehand. Also no answer for the spot color
>>>>> problem, but as long as the user does not limit the used color spaces,
>>>>> things can stay as they are. Just my 2 cents.
>>>>
>>>> so first wen need to test with mixed color space documents and such
>>>> hacks to see what happens (as we don't want invalid documents)
>>>>
>>>
>>> ok. i don't expect any formal problems, only more or less ugly color
>>> shifts. anyhow, we will see.
>>>
>>> needs some thinking about proper examples (colored text, vector and
>>> pixel based graphics in RGB,CMYK,Spot)...
>>> i think 'draw ColorCircle(..)' is a perfect candidate for the complete
>>> graphic part. one page with transparency and also one page without any
>>> transparency (the page group shouldn't kick in). later on we can add
>>> some icc profiles to spice things up.
>>>
>>> i'll start to make a test document on the weekend then. if i have missed
>>> something important, let me know. any additional ideas are also
>>> welcome :-)
>>
>> as a prelude, the next beta will have
>>
>> \setupcolors[pagecolormodel=rgb] % gray rgb cmyk auto none
>>
>> and issue a warning when no model is set when using transparencies
>>
>
> nice. a test document with mixed color spaces is also in work and should
> be ready in a few days.
>

a first version of the test files can be found here (7z, LZMA2 compression)

https://www.wuala.com/indiego/public/?key=caiCGLasLFmJ

i have tested four versions so far.

1. cmyk (default) page group
2. rgb page group
3. cmyk page group + pdf/x
4. rgb page group + pdf/x

no general problems so far (only spot color related)

Peter