The medium as the name suggests, is glass. This technique has several advantages as opposed to any other method of applying paint. Not only does the glass intensify the color, but is also protects the painting against external influences.The visible part of the picture is directly on the glass whereas it is sealed from behind through layers of paint. In addition glass is one of the most stable medium. As opposed to canvas, cardboard or wood, it hardly reachts to the influence of heat or humidity.
The oil paint is applied with a brush. Since it is the back surface of the glass which is to be painted, the artist, resembling an acrobat, has to reach arround the staffold in order to apply the paint from behind.
Thus I see the picture as it appears to the viewer later. Actually it wouldn’t work any other way. I begin with the foreground of the picture, working to the background (in other words painting over the foreground). If I would apply the paint to the surface of the glass which is directly in front of me, I wouldn't be able to see the subject of the picture at all. Thus this technique forces me to work from light to dark, from foreground to the background, as opposed to the technique of painting on opaque surface such as canvas, cardboard etc. where the artist begins other way round. Since the subject or parts of it cannot be painted over, but rather only painted “behind”, the artist, before beginning, must make scheme to define the order in which various picture elements must be painted. Thus in glass painting, as opposed to other painting techniques, there is no coinsidence. It is primarily speaking work, hard work, the creative part being in designing and the color composition.This is the reason why it takes months to complete one artwork. Artworks painted on glass are singular and only artworks in the world painted 3 dimensional on glass.