Dana, that's interesting info.
From what I remember of the analysis done in the early 1980's, mentioned in my previous post, study of the dyes and colour couplers in the emulsion of the 4 x 5 transparency, after examination of any degradation, recipositry etc, strongly suggested that the original colour (as painted) was of a dark green hue, but was possibly a mix of pigments used to make this, with a blue shade very possibly being one of them.
The conclusions at the time only stated that the visible colour, however, was 'green' - no percentage colour spectrum was stated.
Although it's possible that a 'field mix' of paints was used, my personal feelings are that, the paint(s) used to cover the upper-surface AEAF stripes were very probably those that were available at the time, in dark shades, with one of them possibly / probably being Insignia Blue, as used for the roundel of the 'stars and bars'.
Closer examination of the painted areas on the fin etc, strongly suggested that these areas were a different shade again, and were a green hue ( I believe this was some of the RAF Dark Green ).
With a lack, or shortage of suitable camouflage colours in greens / browns, this would have been a logical choice, and, had it been my decision at the time, this would have been 'dulled' at least a little, by darkening it with whatever was available to those ground crew carrying out the work, in order to provide a more neutral 'shadow' tone for use as temporary camouflage on the ground, with the addition of black or a dark grey probably being the available choices.
Of course, this, again, is at least somewhat speculative, but may account for the origins of the reports of 'blue' P-51s, and the eventual change to green(s), which seems to tie-in with info imparted during conversations with the historian at the Bottisham Airfield Museum a couple of years ago.
Cheers,
Terry.