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I was recently asked to reframe an original piece of art which had spent the last couple of years inside a cheap, store-bought frame. When I removed the mat, this is what I found underneath:
At first I thought the difference in colour between the matted area and the rest of the paper was caused by the mat itself as non-archival mat boards contain acids and other pollutants which can react with the paper. However, when I turned the paper over, I realised it was in fact the un-matted area which had been affected and that the damage had been caused by UV light.
Regular 2mm glass, often sold by glaziers as “picture framing glass” offers no protection from the UV rays present in sunlight and should not be used for original works, limited edition prints or anything likely to increase in value, be it financial or sentimental. UV light can be particularly damaging to photographs, breaking down the chemical bonds between the molecules which form the image, causing it to fade over time. Cheap glass also has a green tint to it, which can affect the colours of the artwork behind it, whereas conservation-grade glass often has colourants added to counteract this.
Under the guidelines handed down by the Picture Framers Guild of Australia, conservation-grade frames need to be fitted with glass or perspex which is at least 95% UV resistant. I have worked extensively with perspex in the past, but as a general rule I try to avoid using it for anything other than extremely large pieces when weight becomes an issue. Although it’s less heavy than glass, it scratches easily and has a much higher rate of expansion due to changes in temperature of humidity. In fact, the sort temperature fluctuations which are routine in Australia (not to mention the moisture my clients in the Dandenong Ranges experienced) are enough to cause perspex to expand beyond the 3mm tolerance framers leave inside the frame to compensate, resulting in cracked mitres like this:
Beyond its conservative properties, picture framing glass comes in a variety of forms, each with their own unique features and selling points. A popular option these days is non-reflective glass. Non-reflective glass is a great option for darker pieces, particularly if they are to be hung in a bright area, or for shadow-box frames where the artwork is set back from the glass. It should be pointed out though, that the non-reflective properties really only work when the frame is viewed dead on, and any kind of angle will begin to introduce reflections. There are also differing varieties of non-reflective glass, and for this reason, there are ultimately four different types of glass that I routinely stock.
Tru Vue Conservation Clear
The standard glass I offer my clients is Tru Vue Conservation Clear, which blocks 99% of UV light from reaching the artwork. It’s the most budget-friendly option for true conservation-grade framing and, unless a client requests non-reflective glass (I’m not in the habit of up-selling), this is what I’ll use.
Tru Vue Conservation Reflection Control Glass
Conservation Reflection Control glass is the best option for clients who want conservation-grade, non-reflective glass but would prefer to go with a more budget-friendly option than Tru Vue’s Museum glass (see below). It provides 99% UV-resistance and cuts down on most reflections. However, it should be noted that glass described as “reflection control” features a matte coating which, to some eyes, makes the colours in the artwork behind it look slightly dull. It is also unsuitable for use in shadow-box frames as once it is held more than a couple of millimeters away from the artwork, it’s as though one were looking through frosted glass.
Tru Vue Museum Glass
Tru Vue’s Museum glass is the most expensive form of glazing I offer, but it’s the only choice if you want true conservation-grade, true non-reflective glass. It’s 99% UV-resistant and, being truly non-reflective as opposed to a “reflection control” variety, it’s suitable for use in shadow-box frames like the one below. Please note however that in the picture below, as in the one above, there are still visible reflections (though the reflections on the book itself are due to the mylar wrap holding it in place); nothing is perfectly non-reflective. That said, a black-lined shadow box photographed in a bright room is probably the worst possible conditions for highlighting reflections, and the Museum glass actually holds up remarkably well.
Tru Vue UltraVue Glass
Of course, not everyone has the budget to spring for Museum glass and some people don’t like the look of the Conservation Reflection Control variety. This is why I also stock Tru Vu’s UltraVue 70 glass, though I must point out that this is NOT conservation-grade glass. Personally, I would not frame original works or limited edition prints behind this glass, but it is also important to be realistic when it comes to risk. UltraVue offers 70% UV protection, which is certainly better than nothing, and it’s significantly cheaper than Museum glass which makes it an appealing option to many clients. My preference is for conservation-grade materials but I’m not an ogre about it – just try to avoid hanging the frame in a spot where it’ll be exposed to direct sunlight.
Conclusion
Even at the budget end of the spectrum, the glass is often the single most expensive component in a picture frame, and for good reason because it’s also arguably the most important. As with most aspects of my business, I try to keep things as simple as possible for my clients by using quality materials in everything I do. Unfortunately picture frames, even those fitted with non-reflective glass, are notoriously difficult to photograph so I’m conscious that the picture above perhaps do not do justice to the types of glass they are illustrating. If you’re still unsure whether the aesthetic properties of a particular glass is suitable for your framing job, I’d invite you to visit my studio where you can see examples of them on the walls of a brightly lit room.
