This series comprises three subsets of colour transparencies based on size. 

The material comes in three sizes of 12.50 x 10.00cm, 5.50 x 5.50cm and 35mm. The actual dimensions of the transparencies in their cardboard mounts are 13 x 10cm, 7 x 7cm and 5 x 5cm respectively. 
The 12.50 x 10cm transparencies come in a protective sleeve of plastic, transparent on one side and semi-transparent on the other. 
The 5.50 x 5.50cm format transparencies come mounted in cardboard mounts, and occasionally between glass. Both are used for the preparation of blocks for printing 35mm slides which do not have any protective plastic sleeve over them. 

The transparencies cover a wide range of subjects and assignments.

The International Public Affairs Branch of the Department of Foreign Affairs and Trade assumed control of this series following the abolition of CA 6785, Australian Overseas Information Service on 
7 March 1994.

In 1998 the National Archives of Australia, Reprography Section created an intersorted reference collection of this series which is stored at the National Building in Parkes.