Transparency in scanned line art

[Tonquani]

Hello all!

So I have drawn my map on plain white paper using black permanent markers. I then scan the map in and open it as a png in Gimp. What I now want to do is turn all of the white transparent so that I can start colouring it.

Whatever I do I end up either leaving a white border around all of the black lines, or losing some of the black.

I’m sure there must be a simple way of doing this but for the life of me I can’t figure it out.

Any help would be most gratefully received!

[Abu Lafia]

Hey Tonquani, i hope Colors > Color to Alpha [white in your case], will solve your problem. Since this option will only turn all white transparent, it'l leave other non-white stuff beside the linework (dirt, etc.) on the layer. For generally "cleaning" your scanned linework i usually follow parts of the steps mentioned by Steffen in this Thread. It's written for Photoshop, but most of it is applicable in Gimp too. Since i' usually set my scanned linework layer to "multiply" (sometimes with slight tweaks in Colors> Curves) on top of my color layers (set to "overlay" or "multiply" on top of a parchmenty background layer) i don't need to clean the linework a lot before coloring.
Hope these suggestions make sense...
Cheers,
AL

[Tonquani]

Brilliant! Thanks Abu that was exactly what I was after. I’ll give it a try tomorrow

[Abu Lafia]

Glad it was of help!

[Caenwyr]

Another trick is to duplicate the layer, inverse the colours (so black becomes white and vice versa), and use that as a mask for the first layer. If you tweak the curves of that mask, you can choose pretty accurately which part of the black lines you want to show and which ones need to be invisible. And all of your work is still there if you ever need it