Format

GEM Image

Summary

Name

GEM Image

Identifiers

PUID: x-fmt/159

Format type

Image (Raster)

Description

The GEM raster format (also known as GEM VDI Bit Image; GEM Bit Image; GEM Image; GEM Bitmap; or IMG) is an image format native to the Graphical Environment Manager (GEM) operating system and developed at Digital Research. The format was used by GEM Paint and Ventura Publisher, and by a variety of Atari ST software. GEM raster images may be color, gray scale, or black and white and are always read and written in the big-endian format. The format of bi-level images is well standardized, but the specification is ambiguous as to the format of color images. As a result, other color formats of GEM raster image were later developed, some of which have their own names, such as XIMG (Extended GEM Bit Image), TIMG (TrueColor IMG), STTT, or Hyperpaint.

Format encoding

Text

Note

http://fileformats.archiveteam.org/wiki/GEM_Raster https://www.wikidata.org/wiki/Q28206162 https://www.seasip.info/Gem/ff_img.html https://www.fileformat.info/format/gemraster/spec/20e311cc16f844fda91beb539d62c46c/view.htm https://archive.org/stream/mac_Graphics_File_Formats_Second_Edition_1996/Graphics_File_Formats_Second_Edition_1996_djvu.txt

File extensions

img

Submitted by

Digital Preservation Department / The National Archives

Relationships

Is previous version of

• XIMG (Extended GEM Bit Image)

Internal signatures

Changelog

• V105

  Release date

  29 June 2022

  • Updated

    GEM Image: Updated description and note field. Submitted by Digital Preservation Department, The National Archives (UK).

• V45

  Release date

  6 December 2010

  • Added signature

    GEM Image: Signature submitted by Georgia Tech Research Institute, USA.