[Gimp-user] c2g in Gimp 2.10.12 not performing as in 2.8

[rich404 <forums gimpusers com>]

> you are absolutely right, rich404, i observed the same changes in
> c2g's
> rendering pattern with the version changes in GEGL and GIMP, via GUI
> or CLI.
> now, this is very unfortunate. the c2g algorithm is to my
> understanding truly
> unique and very unusual and special, as it adjust pixel contrasts in
> an 'organic
> or neurological or physiological' way, like the original author stated
> that he
> was influenced by neuro-physiological evidence.
> i feel this precious piece of code would deserve to be properly
> maintained
> within GIMP and GEGL, or be made publicly available, perhaps ported to
> Python3.
> i am not aware of any other (photo) image processing algorithm that
> 'intelligent' to combine data-driven(!) contrast and color information
> from a
> pixel neighbourhood across three channels for the purpose of reducing
> RGB to one
> layer.  i am truly desperate for getting a new c2g version to work
> with the
> appropriate set of adjustable run parameters.  what about a python3
> port ?
> i still have a few linux boxes with gimp 2.8 running but i don't see
> that as a
> good way out of this problem, perhaps as a temporary solution only...


FWIW - You would have to ask the developers (Maybe you already have?)

The closest I can get is the gmic_gimp plugin and the black-and-white filter

but....

It is not consistent. A darker image requires slightly different setting for
contrast and gamma than a lighter image and if you do not know what a Gimp 2.8
c2g looks like, then it is a matter of judgement.

screenshot examples have the Gimp 2.8 c2g as an inset. 

The only advantage with gmic_gimp is

1. Your can save settings to recall them at a later date.

2. It is scriptable.

best of luck with this one.

Attachments:
* https://www.gimpusers.com/system/attachments/1238/original/01-c2g.jpg
* https://www.gimpusers.com/system/attachments/1239/original/02-c2g.jpg

-- 
rich404 (via www.gimpusers.com/forums)