It's Aluminum Composite Material, thin aluminum on either side of a polyethylene core in much the same way as foamcore is paper on either side of a foam core. It's used increasingly in framing. It accepts spray paint well and the surface is considered archival. If you do a search on The Grumble for ACM you'll find plenty of discussions about it.
Yeah. This or a fabric covered liner might be a simpler option at that scale.Mats that scale can get a little problematic. On option is to use a flat plain moulding profile
with a bevel edge and paint it. Not everybody's thing but can be a lot less work and hassle than
trying to cut a 60" mat. Bear in mind that you have to raise the glass away from the painted surface
as you can get strange optical effects when it touches the glass.
Thank you. I did know about these mats. What I need is a mat for something 70 x 70 or so. Larger than 60 x 60 in both dimensions.Crescent has over-oversized mat boards, limited colors...
C2283 white 60x104
C2289 Antique White 60x104
M900104-4 4ply White 60x104
Really? I can't seem to find that. Do you know who sells it?Rising has 72" x 104" mats in White and Warm White.
Me too, but one of the posters said that Rising makes a 72" X 104", and I figured the best way to confirm is to contact the manufacturer.The OP said he needed larger than 60" on both dimensions. I've never seen any matboard larger than 60x104.