Painter's Apprentice is a paint program for DOS, developed by Russell Nelson and Patrick Naughton.
It has native .IPA and .SCR ("scrap") raster graphics formats, and an .FNT font format.
The software is freeware, and there was also a commercial edition with additional supporting material. According to the README file, the commercial edition included documentation of the file formats.
Undetermined, but there doesn't appear to be any good way to identify the files from their contents.