Glazing & Backing

   As with matting, glazing & backing comes in many varieties these days with a variety of prices increasing ever higher with the better specifications. Here are some short lists.

Glazing: Light, especially Ultra-Violet light, is probably the number one cause of deterioration to artwork, & the most detrimental. If at all possible, keep artwork away from direct sunlight or even prolonged exposure to indirect or artificial light. If you have a treasured or important piece of artwork, be sure to use glazing with conservation grade (97+%) UV protection.
  • Regular glass - The standard, also called float glass, & has an iron content that gives it a greenish tinge when looked at edge wise. 90% light transmission, <8% light reflection, blocks about 45% of UV light (not conservation grade).
  • Non-Glare glass - Has a etched surface which breaks up & reflects light. The diffused glare can make it easier to view the art from some angles, but causes distortion from other angles. 89% light transmission, 8% scattered light reflection, blocks 45% of UV light.
  • Anti-Reflective glass - Has a non-reflection coating similar to that used on contact lenses. Allows visible light while minimizing glare, and has a slightly purple cast. 97% light transmission, <1% light reflection, blocks 78% of UV light (not conservation grade).
  • Conservation glass - Has a UV filtering coating which blocks 99% of UV light (conservation grade). 89% light transmission, & 8% light reflection.
  • Museum glass - A combination of the better properties of Conservation glass & Anti-Reflective glass. Very clear, very expensive. 97% light transmission, <1% light reflection, and blocks 99% of UV light.
  • Acrylic glazing (Plexiglass) - About half the weight of glass & virtually unbreakable for framing purposes. Great for larger artwork, but scratches easily.
  • UV filtering Acrylic - Ultraviolet filtering is added to the formula during manufacturing. 92% light transmission, 8% light reflection, and blocks 98% of UV light.
Backing: Foam core has become the standard these days for backing. Stiff, rigid, & stays that way. Although the polystyrene foam is stated as chemically inert, acid free, & CFC free, some conservationist find conflict there & are still questioning it's use & longevity.
  • Foam core - has a smooth, clay coated paper on both sides.
  • Foam core w/acid free papers - pH balanced papers with calcium carbonate buffers.
  • Foam core w/rag papers - 100% cotton rag papers with buffers. Expensive.
  • Heritage corrugated board - A stiff archival corrugated board, 100% alpha cellulose, buffered, no wooden fibers, no optical brighteners, vegetable starch adhesives, etc., meeting many certification standards.
  • 8 ply cotton rag museum board - Not as rigid as foam core, can warp with temperature & humidity, Best for smaller works. Can be used in conjunction with foam core & a deeper frame.