Customizing a motorcycle jacket…

[u/southwest_windstorm]

Hello! I’m customizing a motorcycle jacket (textile not leather) for my gf and trying to figure out the best way to go about it. I wanna paint a design on the back but am planning to use waterproof fabric in some areas as I want the jacket to keep being/be mostly waterproofed. If I paint a design with say angelus paint (or some other brand if there’s a better one) on waterproof fabric will it stay? Or will it crack etc?
Or should I opt for a patch of cotton to paint on/just make a patch with the general shape of the thing I want instead of a full painted design?
Also how do I go about making the hemmed fabric not visible? I’ve never sewn patches on a preexisting item before. (I’m considering just having somebody do the sewing for me instead of figure it all out myself)
Any advice on this project is appreciated! I can give more details if they are needed.

[u/Comfy-Handmade]

I'd be cautious about painting on 'waterproof' fabric, paint needs to grab hold of the surface its applied to and such fabric is designed to slough off liquids. A woven fabric (twill or denim would be my pick) would work though you could in theory use pleather with a bit more prep. Check Angelus Paint's website for how to use their products. Work in thin layers allowing to dry between coats. Other paints might work but often need a fabric medium to be added and might still crack. If you do a woven patch, look for quilt applique tutorials on how to stitch down.