- Its a transparent canvas
- Works great for copying, if starting from a detailed work (line art, complicated writing) easier to reproduce all the tiny details.
- The finished art can be transparent, translucent and incorporate index of refraction effects
- It can be layered and use either further glass layers, traditional canvas as a backdrop, or be shown in a way that exposes the scene behind. [1]
[1] https://www.artsyshark.com/2020/11/26/featured-artist-michael-frank-peterson/
- It can be easily backlit / sidelit
- It allows focusing on details if the art being produced is very detailed or line art in style
- It can often convey depth easier because of the translucent quality of the thick layers of paint
- Some pigments adhere better to glass than to traditional canvas, allowing other colors and mixtures normally difficult with canvas
- Techniques normally not available, like flowing, dripping, runny water (that would normally be absorbed) can be used. [2]
[2] https://iranian.com/Arts/1999/September/Azima/waterfall.html
- The reverse layering often makes foreground features standout and be "crisp" as they completely dry and there's very little chance of smears or blending [3]
- Techniques like using black additions behind colors to intensify them or increase contrast are available [3]
[3] https://upload.wikimedia.org/wikipedia/en/f/f2/QingDynastyArtist-LargePartyatThrone.jpg
- The finished art can easily be used for windows, portals, dividers, and other areas normally meant to be transparent (fishtank walls)
- It can be adapted to almost any material that's transparent (plastics, colored glass, consumer objects)
Disadvantages
- Details need to done first
- Means you need to have a really good idea of what you want to paint beforehand
- You can't miss any details, because otherwise you'll have scrape away large areas of paint to correct
- Can often take a long time checking and re-checking to make sure you didn't miss anybody's eyebrows or other tiny features
- You can't change your plans midstream, or improvise very easily
- Or the changes / improvisation need to mostly affect the background objects
- Its transparent glass (or it's not traditional canvas)
- Many of the art supplies and paint don't work the same (or even at all)
- Ex: Watercolors don't get absorbed and diffuse
- Several traditional art materials need additional adhesive layers to make them actually attach to glass
- Techniques available on canvas may not be available or have to be completely redesigned
- The painting surface itself is usually fragile, and significant risk of breakage / damage
- It's often historically been stigmatized (viewed as an art style of primitives, religious people, or "feminine")
