Enamel and Cellulose paint history/practice

[JonE]

Peter - did the brown primer almost look like Auto Brown - i.e. was it a polishable layer? I've been looking at the 1932 cards (or rather the ATDC report on them) trying to get more evidence on the blues which are sorely missing. The trouble is, there are match suggestions given (the one for Opal blue equates to RAL Fir Green - of which I get no discernable blueness in) whilst it is abundantly clear that those earlier cards have darkened! It would be great to learn more about the Postan "Seven" Blue and Opal, neither of which have any old fashioned percentage constituents recorded. Looking at the early make-up of Royal Blue ("95% Prussian Blue") I suspect that the 1936/9 Royal cards could well be darker too. I just screen colour matched what was evident but ended up using 400ml of "Superblack" to dull the litre of Dark Teal down but probably ended up with something which WAS Royal in that it largely looks RAL Prussian Blue!