before & after

Often art will arrive in the shop previously framed.  Acid-free materials became readily available during the 1980s, so pretty much any matted art that was framed before then is in an acidic and potentially harmful environment.  UV protectant glass is a modern convention as well.  Any competent framer should be able to let you know at a glance if your mats are acid-free or your glass is conservation coated.

This great abstract framed print came in for a complete overhaul.

In this case, the artist had titled and signed the original mat.  I would never recommend anyone to discard anything in the artist's own hand.  But I would also not recommend this mat to come in direct contact with the art.  Signs of foxing are present in just the small part of it I can see.

I cut a 2ply acid-free mat to go between the art and the original signed mat.

Then the original mat went back on--this time making no contact with the art.

Two new mats were cut to go on top: a wide gauge linen and a sliver of green.  Add UV glass and a handsome walnut burl and this is one class act.  Warm colors, texture, classic design.

before & after