Color to alpha: for cutting out line art

(this is not about Lineart, Freestyle successor)

It's not obvious how to properly remove white background from a sketch. Here's one tutorial on how to do it: tutorial by Monika Zagrobelna

You can prepare a setup to automate this technique in Blender, which really comes down to opening an image in a shader like this:

and rendering it without sRGB color transform. Then, if you take image A, and remove the white background, you can replace it like with the colorful cloudy animation, and all edges stay nice, without the white color known as "halo effect". You can also put this new image B on top of the white background, producing exactly image A, which proves the background was removed correctly.

👉 The blend file also has an “autofix” Python script attached, that will set scene dimensions to the image dimensions, as well as set the color space to ‘Non-Color’ in the case you forgot it.

⚠I promise no support and give no guarantee the item actually works❗ You’re buying junk! Treat it as an educational material rather than a product. However, I’d love to hear any kind of feedback: bug reports, suggestions, ‘backlinks’ to your work that uses the obtained junk (if you decide to share, please provide info if I can use it in the description of the item). Based on that I may tinker with an idea some more, but no promises are made.

Within the package:

✅ A color2alpha.blend file with a setup to remove a white background from a line art image. The output image will be a grayscale image.