The canvas varnishes have always looked a little veiled to me, not perfectly 100% transparent. And I have tried all the variations from many coats to 1 coat, from thick to thin, through special top coats, and everything in between. It goes beyond surface characteristics, it's in the paint itself.
That veil may be a compromise that comes from having to maintain "stretchability" for wrapping. For most canvas users that's the most important thing, and little else seems important when your corners are cracking. But to my eye, the solvent based coatings are more transparent, and and seem lay down very easily on smooth surfaces with almost no fuss at all.
I need to do some more tests, of course! But when I started seeing what those cheap solvent spray cans were doing for both my canvas and Canson Rag test strips, it gave me cause to think.
Of course, roll laminates also have a veiling effect, or at least the ones that I have seen, especially when viewed with light to my back. So for my money, solvent sprays will probably give the best looking coating results, while being in all other ways pure evil.
