On 18/06/2019 2:46 am, yorkshireman@y... wrote:
> Kirk’s correct,  the younger they are, the lighter they get.  The original
colour is dark blue, and I had a reference to it being RAF Roundel blue - but
the precise blueness of that is unknown to me.
Regarding the precise blueness of 'roundel blue', that colour is 
documented in British Standard 381C (Colours for Specific Purposes). 
It's number 110.

You can see the colour of roundel blue expressed in various ways here:
http://www.perbang.dk/rgb/183070/

-- 

Peter Marquis-Kyle
www.marquis-kyle.com.au