Zomerzegel 1970

Computer Graphics for Philatelists

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virtual exhibit
Fall 2014 / May 2026
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With the Zomerzegel of 1970, a yearly edition of summer-stamps, the Netherlands surprised philatelists worldwide: For the first time computer graphics were presented as stamp-motifs.

Ootje (R. D. E.) Oxenaar

Ootje Oxenaar designed the stamps and developed the five computer graphics in cooperation with the Technical University Eindhoven.
Back then Oxenaar also worked on an innovative design for new Dutch banknotes. In cooperation with the TU Eindhoven he used thin, computer generated lines in the background of the main motif to make it unforgeable. These lines were calculated by a mainframe computer and were (in these days) practically not imitable. The mainframe used at TU Eindhoven was CORA I.

This design process brought up the idea of choosing computer graphics as motifs for a stamp edition.
See images of the dutch banknotes and other work by R. D. E. Oxenaar on the website of the Alliance Graphique Internationale

Summer-Stamps and Computer

On April 7, 1970 the computer graphic stamps were released. The PTT also distributed five first day postcards »Zomerzegel en Computer« — Summer-Stamps and Computer:

The original titles of the motifs used by Ootje Oxenaar were:
Zomerzegel 1970 12 + 8: isometrische projectie van circel naar vierkant (isometric projection from circle to square)
Zomerzegel 1970 15 + 10: evenwijdige vlakken in en kubus (parallel planes in a cube)
Zomerzegel 1970 20 + 10: twee schaalverdelingen (two scales)
Zomerzegel 1970 25 + 10: overgangsfasen van concentrische cirkels met oplopende diameter (transitional period of concentric circles with gradient diameter)
Zomerzegel 1970 45 + 20: vier spiralen (four spirals)

Artist's Profile

Robert Deodaat Emile (Ootje) Oxenaar (1929-2017), born in The Hague, The Netherlands, graphic designer, studied art in The Hague, worked as professor for industrial design at the TU Delft and for the department of aesthetic design for the PTT (post administration of the Netherlands) between 1970 and 1996. Oxenaar emigrated to the U.S. in 2000 where he taught at the Rhode Island School of Design (RISD), Providence.