Re: [ gnuplot-Bugs-1575425 ] "with image" ignores gamma for postscript output (fwd)

[Daniel J S. <dan...@ie...>]

Ethan Merritt wrote:
> On Wednesday 11 October 2006 10:07 am, Petr Mikulik wrote:
> 
>>I have just filled in the enclosed bug (announced to me by another
>>gnuplot user) ... could someone figure out an appropriate "filter"
>>for the postscript "image" operator so that the gamma correction
>>works also for "with image" as it works for "with pm3d"?
> 
> 
> Shouldn't the gamma be a per-image correction rather than something
> to do with the current palette?  I would have thought that the
> gamma correction belongs in the routine that reads in the data.
> That makes it terminal-independent.

Well, I was just writing a reply and wondering that myself:

....

Hmm, well let's see.  I think one of these is preferred over the other, but not sure which.  With (2), would that mean cb2gray() is altered in some way?  Or is there another function that would be applied?  E.g., gray2gamma(cb2gray()).  Don't know... I think conceptually we'd like to keep our data non-tranformed.

I kind of like the way "test palette" behaves.  That is a really powerful tool in a way.  I'm thinking to avoid (2).  Agreed?

...

Let me point out something else I've noticed.  Using "test palette", the gamma correction looks different between X11 and PostScript.  Or at least it looks that way to me.  The reason I say that is because in the X11 output I can't see the "0" within the black area, but I can see "0" within the black area in the PostScript file.

Dan