Color to transparency

[Christoph_T]

Hello together,

since some years now I am painting with Gimp 2. (2.8.22 latest).
Mostly I am doing repaints for flightsims like P3D and X-Plane:
X-Plane: https://forums.x-plane.org/index.php?/fo...nt-1238872  
FSX/P3D: http://www.sim-outhouse.com/sohforums/sh...nting-room

Recently I moved to Gimp 2:10 which has some great new tools.
One thing that I miss however is the tool "color to transparency" which was really great to create nice overlays.
I know that there is the tool color to alpha but sadly it doesn't work as well for me
The new maps are kind of washed out. With blending out the a white tone for example all other colors are also more greynish than with the "color to transparency tool".


I would be very pleased if anybody could help me out to find a workaround to get the same results as with the old tool.
Maybe there the is also a way to get the old tool back to work in 2.10?

Many thanks in advance for any advice,

Christoph

[rich2005]

I compared a complex image with color-to-alpha (c2a) Gimp 2.10 - both default and legacy layer modes and Gimp 2.8 

Visually look the same to me, lots of color picking and no real significant difference.

screenshot: https://i.imgur.com/kFNHBd9.jpg

If there is going to be any difference, my guess is the default/legacy layer modes and maybe the colour mode sRGB/linear. Also check Edit -> Preferences -> Color Management, set it to off.

However, Gimp is built around plugins and c2a is no different. Attached is the Gimp 2.8 c2a plugin (64 bit)

Unzip it. Put the file color-to-alpha.exe in your Gimp 2.10 profile (No guarantees with this one although it does work )

C:\Users\your-name\AppData\Roaming\GIMP\2.10\plug-ins

Find it after the GEGL c2a entry towards the end of the menu. 
example: https://i.imgur.com/ApCmsz3.jpg

[Christoph_T]

Hurrey :-)
Thanks rich2005!!!
It works perfectly for me:-)

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To give you a better description of my previous problem.
This is the good one (looks the same like the original PNG).
You see a simple white layer with the overlay (white to alpha) on top:

On the second image you can the my results with the "Color to alpha"-toll from Gimp  2.10:

These are the settings used:

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Thanks again for your quick help.
Very much appreciated :-)