blood Envelope grunge grungy letter mail message note notes paper post red retro spatter splat stain stained stationery vintage aged backdrop background frame notebook notepad old pad photo picture tags tattered torn worn backdrops backgrounds blank colors colours copyspace desktop pastels pin scrapbook slides tack wallpaper button cardboard collage corrugated paint splatter color colour hue hues metal rust rusty texture tint tints variations various abstract biological biomedical bone cancellous contrast dic differential interference medical microscope microscopy spongy sub-chondral sveres trabecular vertebra vertebrae