A word about glass. There is something called ‘anti-glare’ or ‘non-reflective’ glass.
A proportion of the light that falls on the picture hanging on your wall is reflected back off the glass and doesn’t get to the picture. This has a number of effects, not least of which is that the colour, the tonal contrasts and the brilliance of the image are diminished. This effect is, of course, to a greater or lesser degree dependant on the local lighting conditions. Another effect is that the glass becomes a partial mirror, reflecting the room.
A solution to these problems is non-reflective glass. You need to be aware however that the quality of this type of glass varies tremendously. There are side effects. One of these, in the cheaper types, is that the detail contained within the image is reduced. This may not necessarily matter too much if the type of image isn’t compromised by this particular effect. An example of this would be an image with little or no detail anyway like simple splashes of colour and very little else. Watch out for contrast reduction though.
The most expensive types of non-reflective glass however use more sophisticated techniques to achieve their results. They are excellent, but very pricey. They’re worth it though. After all, why would you put a low quality filter in front of a high quality lens with the inevitable consequences?
Beware … all glass is not the same.