How to Add Emissions to Custom Textures!

addam davis
3 min readMay 16, 2022


Objective: Add emissions to custom textures using Gimp!

Emissions are a texture that illuminates, it is like a luminate channel that would be in a 3D program. Emissions work differently on regular versus static. Dynamic elements, the emissions will only emit a glow, and for static elements it will actually illuminate the area using the built in GI system.

In this tutorial I’m going to take the sci-fi test tube and I’m going to make the green bit be the illumination point.

First locate the Texture file.

Open the file location and drag this into Gimp.

The transparency sections are the green bit. This is the part we want to select and manipulate. Create a new layer.

With the base layer selected, choose the channels tab and select the alpha channel. Right click the alpha channel and select ‘add to selection.’

We need to invert the selections by selecting the selection tab and clicking invert, or CTRL + I.

Unselect the alpha channel and choose the bottom layer. Use the fill bucket to fill in the selection with white paint.

At this point we can get rid of the base layer we no longer need it.

We need to fill in everything that isn’t white with black. Everything we made that was white will create an emission and everything else that was painted black will not.

It’s time to save this. I like to keep the name the same and just add _Emission at the end of the file name.

Don’t forget we need to export this as a PNG file.

In Unity, select the test tube and in the inspector, there is an emission options, turn it on.

Take the emission map we just created and drag it into the emission map slot in the inspector.

Now you can choose the exact color you want and the intensity of the emission.

Don’t be afraid to experiment with your emission mapping or with the inspector options. I’ll see you in the next tutorial!