Ishihara Test

Through my research I have found out that colour blind diagnosis was a UK First, identified by English Chemist John Dalton in 1897 and the term Daltonism used to be used to refer to condition although it is now referred to as deuteranopia. 
In relation to this I thought a series of stamps that use the Ishihara Colour Blind Test to convey Daltons original diagnosis of the condition.
Example of the Ishihara Test - six specific colour combinations to use on the stamps:

Whilst looking for six different colour combinations to use I stumbled on this poster for the Obama campaign. The Ishihara test has been used to highlight racism with the tagline 'Vote for change, not colour', a clever application of the test using the Democrat Party logo in the design. I could use the Queens head in a similar way. 

I also found this series of icons on a google search, unfortunately the site they are on isn't working so I'm not entirely sure what they are for. The number 9 is a good example of using the test to create numbers, something I'll also try in addition to the Queens head idea.