Glazing can be either glass or acrylic. computer Only glass should be used with any friable media such as unfixed pastels, charcoals, wildlife clip art or graphite, art never acrylic as computer it can damage the work by attracting these materials. there are many brands of acrylic glazing to choose from; one with an ultraviolet filter is recommended. the frame and the mat should be deep enough to prevent the artwork from touching the glazing. a stiff backboard behind the mat anniversary clip art protects and supports the matted artwork. it is best to use non-acidic boards. a dust seal with paper or tape is also recommended. what damage results from using poor quality mat board? avoid mat boards containing wood pulp which causes "matburn"--a darkening of the paper under the mat or at the bevel cut of the window mat. this type of stain permanently weakens the paper fibers art and is not easily removed or lightened in conservation treatment.

what is the cause of dark spots that sometimes appear on the paper of drawings and computer paintings? reddish-brown spots anniversary clip art are known as "foxing", caused by mold or the deterioration of the metallic impurities left in the paper from the manufacturing process. other colors of spots may be one of many types of mold damage. mold spores are everywhere in the environment, and mold thrives on cellulosic materials, art especially in conditions of high humidity (above 65% of relative humidity). keeping artworks out of high humidity areas like bathrooms or exterior walls, can help reduce the development of such stains. if i have a work computer and clip of art on paper that appears to not be flat, should i be concerned? paper is hygroscopic, reacting to changes in climate by expanding when it is humid and contracting when it is dry. a gentle undulation in the paper called art "cockling" occurs under these conditions, especially with larger works. this may impair the work aesthetically as well as cause mediums such as gouache to crack or flake as it is unable to expand and contract as the paper computer and clip and art itself does.