While I always recommend you have your print framed by your local Custom Framing studio, professional-quality results can be obtained at home as long as you keep a few key points in mind.
Online framing resources (I like Graphik Dimensions ) usually offer several grades of material and it's important to understand their differences.
The glazing can be either glass or acrylic (plexiglass) and protects against two potential sources of damage: physical contact and Ultraviolet light. Both materials offer potential advantages. Glass is thicker, more rigid, and more scratch-resistant but is easily broken (un-shippable). Acrylic is lighter, thinner, and shatterproof (shippable) but is more easily scratched. With either, you'll have to specify clear or matte finish, "plain" or UV-resistant coating .
Matte finish is a chemical etching of the glazing's surface that will cause a slight decrease in perceived sharpness of the image but dramatically reduces glare.
Ultraviolet light is emitted from indoor lighting as well as the sun and will degrade both the paper and the ink or pigment of the print over time. Uncoated glass or acrylic filters 50% or less of UV light whereas glazing with a UV-resistant coating will filter 90-98%.
Matting also serves a protective purpose: it separates the print from the glazing. The mat is a paper product and is available in three broad categories: Regular/Economy, Conservation/Archival, and Museum Board.
Regular/Economy mat is plain paper, processed from wood pulp, which unfortunately is acidic. This acid content will yellow or "mat burn" the print over time.
Conservation/Archival mat is typically a lignin-free wood pulp product but can also be cotton rag. Archival mat is acid-neutral and usually rated to be inert for 100-300 years.
Museum board is the highest quality mat material and is composed of 100% long-fiber cotton rag. It is rated to be inert indefinitely.
The backer board is typically made of either corrugated cardboard or foamcore matboard. Corrugated cardboard is very acidic and is really only appropriate for short-term use, such as framing an annual business license. Foamcore matboard is offered in the same grades as the mat material (museum board does not have a foam core) .
Assembly of the parts is pretty self explanatory but there is one more problem: how do you attach the print to the mat/backerboard ? The trick here is that you do NOT want to rigidly attach the print to either surface. Changes in humidity or temperature will cause the print to shrink or expand, causing a "warp" or a "wave" to form. If your framing kit came with mylar framing corners, attach those to the backerborad and insert the print (leave just a little wiggle room) and lay the mat over the top. If your framing kit did not come with mylar corners, you'll need to use acid-neutral artist's backing tape - attach the print to the back of the mat, but only tape along the top edge (use a "T" hinge -illustration here ). Mounting this way will accommodate expansion as well as simplify re-mounting in the future.