: GIMP Color to Alpha removes color In GIMP, when I use "Color to Alpha" to remove the dull blue background of this image: It removes some blue from the entire image, so most of the image

@Dunderdale640

Use a selection so that color-to-alpha is only applied where needed:


using the fuzzy selection, select the background. Shift-click any closed areas (inside of 'O','P','D,'A', etc....) to add it
Select>Grow by 2 pixels to include all the edge pixels in the selection
Color>Color to alpha.


PS; You have strange artifacts around the big squares (the background isn't as uniform as it looks) so using C2A alone will leave some opacity in the background. A more complete approach can be:


Make fuzzy selection as above
Save selection to channel
Select>Shrink by 2 pixels and [delete]. This insure that the background is completely clean
Restore original selection from channel
Select>Grow by 2px and C2A.


This more complete method is partially automated in the ofn-erase-background script.

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