Does anybody know/have ideas how to make velvet effect background in Adobe Illustrator 5.x?
An example I'm talking about:
This is something you would use in Illustrator not make. It appears to be a scan of a painted surface or multiple painted surfaces composited.
Photoshop is the app you're looking for. When you're ready to apply it to your Illustrator artwork, just
Place the image as a linked graphic.