Cambridge University Machin Colour Trials of 1969 - Part 3

Part 1 is here. Part 2 is here.

Arnold Machin maintained a close interest in any changes in his design, so he was consulted by Don Beaumont about the 14 proposed colours for the decimal series. Machin was not satisfied with them on aesthetic grounds.

Machin created a new range of colors which was referred to as the 'Machin' set of stamps.

In their subsequent second report, the researchers noted in response that their selection criteria had not taken aesthetics into account.

Another range was produced by one of the researchers named Brown. Brown's set was based on the argument that the recognition of a color visually was retained in the brain for only two seconds. After that, the brain stores the memory by name. Therefore, a stamp that can be identified by a simple name such as 'red' is remembered better than one that is 'pinkish head on a dark green background.'

Both new sets contained colours that were not part of the original selection.

The researchers stated that it was impossible to construct a range of 14 colours that can be identified and described as a single word, especially when considering the other constraints such as compatibility with automated sorting.

It would, however, be possible to use different hues of the same color. 'Bright blue' and 'dark blue' are easily remembered, though the previous investigation showed that dark colours are difficult to identify quickly.

The researchers did comparison exercises (see Part 2) with the 'Machin' and 'Brown' sets. Those two sets gave similar results, but both produced more errors than the original set, and 80% of those errors came from the newly-introduced colours.

They came to several conclusions, including that it was probably impossible to design a range of stamps this size that is both maximally pleasing aesthetically and minimally confusing.

After the second report was submitted in September, 1969, a decision had to be made. Don Beaumont selected 12 colors and had trials produced showing the colours with their proposed values. He then consulted with others in the Post Office, and as a result he switched the colours on some of the values.

On the four colours shown above, the 1 1/2p, 2p and 3p were retained, but the gradated pink colour used for the trial of the 7 1/2p was now proposed for the 2 1/2p.

The full set of 12 is shown here. On this full sheet, note that the 7 1/2p is printed in two colours, gradated pale blue and gradated pink. This implies that in this late 1969 effort, several colours were trialled for at least some of the values.

The 12 decimal definitives were issued on February 15, 1971.

As we know, the 12 colours didn't last long. The 10p was changed from a large stamp to a small one and issued as a bi-coloured stamp (terracotta and orange-brown) in August, 1971.

Three new values, the 4 1/2p bluish grey, 5 1/2p deep violet and 8p red were issued in October, 1973.

To see the progression of colours throughout Machin history, see the timeline on Robin Harris' superb web site here.

--Larry