I'm writing my first tutorial for this easy technique:
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Just follow the instructions!
1.) Crop you image to 100x100
2.) Duplicate the base and set the duplicated image to screen at 80%
3.) Duplicate the duplicated screened image and set it to color at 100%
4.) Make a new raster layer and fill it with the color #234c7a set this layer to exclusion at 70%
5.) Make a new raster layer and fill it with #000040 set this layer to exclusion at 100%
6.) Make a new raster layer and fill it with #c0c0c0, set it to burn at 100%
I tried out this tutorial with some other icons and this is what i got: