BMG (Bert's Coloring Programs)

File Format
Name	BMG (Bert's Coloring Programs)
Ontology	Electronic File Formats Graphics BMG (Bert's Coloring Programs)
Extension(s)	.bmg, .ibg
Released	≤1993

BMG is a raster graphics format associated with a set of DOS programs for children collectively described as Bert's Coloring Programs. There is also at least one non-"Bert" program that uses BMG format. The programs were developed by Theron Wierenga.

A BMG file is structured as a standard PCX file, always 560×480 pixels, but unfortunately its colors are not interpreted in the standard way.

Discussion

Programs known to use BMG:

• Bert's African Animals
• Bert's Christmas
• Bert's Dinosaurs
• Bert's Prehistoric Animals
• Bert's Whales and Dolphins
• Rachel's Fashion Dolls

Similar programs by the same author that do not use BMG format include Bert's Dinosaurs v5.0 for Windows, and Peter's Warbirds / Peter's Airplanes.

Each program uses a fixed 16-color palette, but the palette differs by program and version. The correct palette is usually not written to the file (one exception seems to be Bert's Christmas v3.2). The palette in the file may be all-black, or may just be wrong.

You can save an image using one program, then load it into a different program, and in many cases its colors will be different.

(Sure, changing colors is the point of this type of software. But this isn't a great way to do it.)

Identification

For what it's worth, it seems possible to distinguish BMG from other PCX files, with good reliability. The first 16 bytes of a BMG file, and the 10 bytes at offset 64, are probably always the same, and some of the fields there are fairly distinctive. And there are probably only a few possibilities for the 48-byte pseudo-palette at offset 16.

Software

• Bert's etc. (selected releases)
  • Bert's African Animals v3.0
  • Bert's African Animals v3.2
  • Bert's African Animals v4.6
  • Bert's Christmas v3.2
  • Bert's Christmas v4.6
  • Bert's Dinosaurs v3.2
  • Bert's Dinosaurs v4.6
  • Bert's Dinosaurs for Windows v5.0 (for reference)
  • Bert's Prehistoric Animals v3.0
  • Bert's Prehistoric Animals v3.2
  • Bert's Prehistoric Animals v4.6
  • Bert's Whales and Dolphins v3.0
  • Bert's Whales and Dolphins v3.2
  • Bert's Whales and Dolphins v4.6
  • Rachel's Fashion Dolls 2.6

Sample files

• Each release includes an example .BMG file, and an .IBG file (same format, for internal use).