Thursday 7 October 2021

Machin Postage Stamps 3

I've done some investigation into Machin stamp designs that take into account colour vision deficiency (CVD). In particular, I looked at CVD-safe colour schemes and visual representation of numerals for the denominations. See those three web pages for more details.

The numeral scheme I finally came up with (after a lot of experimentation) is as follows:

The symbols have the following properties:

  1. The number of small dots is the value of the digit.
  2. Each has a high-contrast, CVD-safe colour (from the 'Chilliant Pale/Deep 19' palette).
  3. The outlines are distinct.
  4. They all fit within a circle the size of the grey ring zero.

For dark backgrounds, simply switch the pale/deep pairings:

The names I've ascribed to each of the symbols are:

  • 0: grey ring
  • 1: slate circle
  • 2: brown oval
  • 3: purple triangle
  • 4: cyan cross
  • 5: green bowtie
  • 6: pink star
  • 7: blue heptagon
  • 8: orange square
  • 9: mint lozenge

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