Factorio Forums

Am I allowed to create and distribute a mod by modifying existing Factorio content (e.g. a new item by taking sprites from data/base/graphics/ and recolouring it for say a new fluid), and is the terms and conditions for doing so formally documented somewhere?

Yes it's allowed. No it's not formally documented. viewtopic.php?p=49122#p49122

I read the question, my answer is... Well, it better be! I've been doing it for years!!!
I even re-introduce old icons sometimes.

If you just want to recolor an entity without changing the graphics otherwise, you can just add something like tint = {r=1.0, g=0.8, b=0.0, a=1.0} next to the relevant filename in the prototype definition.

This doesn't seem to work for icons though, you still need to copy and recolor them manually.

Although that works, the entire entity is recoloured.

what I did for some of them was create a mask to recolour only part of it.