1306 Polynomial Texture Map Image (Raster) Developed by Hewlett Packard, Polynomial texture maps (PTMs) are an extension to conventional texture maps that allow enhanced image quality. As opposed to storing a color per pixel, these PTM’s store second-order bi-quadratic polynomial coefficients per pixel. These polynomials model the changes that appear to a pixel color based on either light source position or viewing direction. 1 Digital Preservation Department / The National Archives 01 May 2013 01 May 2013 fmt/519 PUID ptm File extension 812 Polynomial Texture Map BOF: PTM_1.2.PTM_FORMAT_ 1 Absolute from BOF 0 0 50544D5F312E320A50544D5F464F524D41545F