All openings are reduced by 1/2" to overlap the picture size referenced in the listing. All of our matting is bevel cut and has a white core. This listing is for picture matting only Made from 4 ply high quality matboard These are high quality 4 ply picture mats cut for the picture size referenced in the title. All openings are reduced by 1/2" to overlap the picture. All of our matting is bevel cut and has a white core.