Light damage is gradual, and irreversible. Artwork or prints should never be exposed to direct sunlight from windows, especially early morning or evening when the sun is low in the sky and UV exposure is greatest.
Light enters rooms from windows and bounces from walls and ceilings. This indirect light is less damaging of course, but this exposure is often overlooked. We use a UV Protection glass which has a filter that absorbs 99% of the damaging ultraviolet energy. Vulnerable items include fabrics, cross stitch, needlepoint, silks, watercolours, papyrus, and sports shirts with signatures.
Method of Framing
The glass is sealed to the foamboard and window mounts, with a conservation white paper tape called Filmoplast P90. This sealed package prevents the intrusion of dust and small insects, and fits neatly into the frame rebate.
If necessary we sometimes use a small spacer placed under the rebate of the frame. This gives a small air space between the artwork and the glass allowing any condensation which may form on the inside of the glass, due to sudden temperature changes, to gradually dissipate without affecting the artwork. This method is very useful for embroideries. A double mount will of course do the same job as a spacer, and gives about a 3mm air space.
Finally, a solid 3mm medium density board, or an archival corri-cor board is used as a final backing and sealed with gum paper tape, so essentially the frame is double sealed. Felt pads are placed on the bottom corners of the frame to allow an air space between the picture back and the wall, which promotes air circulation.
Mounting Prints and Artwork
Our Conservation method of attaching prints and artwork on paper is to use gummed Mulberry paper T-hinges on a conservation mountboard or foamboard. Only about 5mm of the hinge is actually fixed to the artwork. This enables the hinge to break at the crosspiece of the hinge if the frame receives a violent shock, without tearing the artwork. Two hinges are required for most items, placed about 3cm from the top corners.
Paper should be able to expand and contract with the change of humidity therefore the paper should never be taped all around the edges as this restricts movement causing cockling, the wavy undulation of the paper which is difficult to rectify.