Multi Tasking
nother thing the matte is designed to do is maintain a space between the drawing and the glass. This is absolutely essential to avoid mould and fungus appearing (and growing) on both the paper and the inside of the glass in very short order. Even though you would think that once safely framed, your drawing is in its own clean, moisture free world, this is actually not the case at all. Everything in this world has got a percentage of water and bacteria in it by default. Paper most certainly has. In a properly framed drawing the only thing in there with your piece of paper between the glass and the core-board backing is the matte and some air (apart from all the moisture and bacteria of course). Matte very effectively acts as a humidity equaliser as the paper gives off and takes up its moisture content as time passes. For an instant demonstration of the worst case scenario you have only to let bright, direct sunlight hit your framed drawing for a few minutes. Drops of condensation quickly form under the glass once the temperature in there starts to rise. Once the work is moved back into the lower temperature of the shade, the drops of water are slowly re-absorbed by the matte board. Also by the paper and wooden moulding as more time passes and the moisture content becomes equal throughout the various materials.
