Issues with color to alpha borking background color. - Printable Version +- Gimp-Forum.net (https://www.gimp-forum.net) +-- Forum: GIMP (https://www.gimp-forum.net/Forum-GIMP) +--- Forum: General questions (https://www.gimp-forum.net/Forum-General-questions) +--- Thread: Issues with color to alpha borking background color. (/Thread-Issues-with-color-to-alpha-borking-background-color)

Issues with color to alpha borking background color. - kulharin - 01-20-2025 I am experiencing an issue trying to add semi transparency to this spectre and full transparency to the grey background.   I select the entire image and choose color to alpha, I select grey as the color... If I set the threshold (too low I guess) and it seems make the background this dark blue/green color that is not transparent at all?  What am I doing wrong? RE: Issues with color to alpha borking background color. - rich2005 - 01-20-2025 Is that the only image you have ? Do you have the symbol and the "spectre" as separate images ? If you have then post them. RE: Issues with color to alpha borking background color. - kulharin - 01-20-2025 I do not, it is an in game screenshot from Skyrim. Intended for use with this mod. https://www.nexusmods.com/skyrimspecialedition/mods/123521 ... So they need to be from in game during an active animation with the applicable effects. I use an in game review studio that allows me to spawn creatures inside a white, black, green or blue room, which becomes the background. I have been using the fuzzy select tool for some creatures, which can be a tedious pain depending on the creature. But the ones that are fully semi transparent I have issues with color to alpha. RE: Issues with color to alpha borking background color. - denzjos - 01-20-2025 Not perfect but I tried this: Copy the original layer and desaturate the layer(Colours / Desaturate / Mono mixer - play with the sliders) Set the other original layer not visible Copy the desaturated layer,optimise with: Colours / Brightness Contrast - use contrast  and remove white background with: Colours / Color to Alpha Set the desaturated layer not visible Copy the desaturated layer a few times to darken the object Make a new layer with this layers : New from Visible and set the desaturated copied layers not visble Select the dark object with the fuzzy select tool, and make a copy from the original layer Select one of the copies and 'Add Layer Mask' / From selection Copy this layer and invert the layer mask from this layer :    Colours / Invert Play with the layer opacity A small example from the original : [attachment=12919] RE: Issues with color to alpha borking background color. - rich2005 - 01-20-2025 Still not sure what is required Instead of fuzzy select maybe use color select to obtain a white BG (leave alpha off for the moment). Color select with draw mask enabled - click and drag to define a selection then Edit -> Cut then Select -> None. Now apply color-to-alpha and you might have more success with the white BG. Sometimes the eraser tool in anti-erase mode can restore parts of the image. For tweaking transparency. The curves tool using the Alpha channel. Some of that might / might not be useful. I can just get it into a 60 second animation https://i.imgur.com/0WrmryZ.mp4 Another possibility is the gmic_gimp_qt plugin which has an interactive-extract filter, but that is different story.