... I wonder if the look of a paint not exposed to the sun is necessarily more accurate than a chip exposed. Observing the scans of the Nakrasok alboom, I suspect that the bonder of the paint becomes yellowish if not exposed to the light.
Paint yellowing or darkening present on many old paintings in gallerias and churches is better described as
aging, not weathering. Paint aging is caused by extremely slow processes within the paint (changes in relatively unstable pigments or media that were used) and reactions with aggressive chemicals from the air (smoke, H2S, etc.).
In case of preserved samples of Soviet paints from 1930-40es, paint aging is negligible. First; those samples are "only" 70-80 years old. Second: paint technology made huge progress in 20th century, so modern paints are generally better quality than those mixed several centuries ago.
Weathering is a different problem: it is caused by UV light, moisture (rain, snow) and extreme temperature changes. If those adverse factors are removed, there is no weathering.
If plane had been stored indoors, in dry and shaded environment, weathering is negligible too.
Following photo shows how severe was paint weathering on le Bourget I-153
Paint under the leather coaming was protected from UV light and moisture so the paint looks almost as new... The rest of the paint is bleached, faded, chalked...
Alex Gorodnichev a russian friend of mine agree with that .
According to him a ggof reference can be the color of this engine:
He think the SB-2 seems bluish because the plane is wet with the rain and the pic very flashy
other part of the SB-2 shows a beige tendance:
Hi Xan,
Alex is my friend too, he helped a lot in revealing the history of Musee de l'air Stratostat gondola.
Just for the sake of accuracy:
- engine crank cases were painted with special paints (check colour table at research pages) that were more resistant to engine oil/ fuel spills and high temperatures - so green-gray paint on your engine photo isn't AE-9
- paint remnants in SB rear cockpit are almost certainly green ALG-1 and steel gray A-14
... we have here a quite goood idea of AE-9 light grey with a little beige tendance...
According to wikipedia beige is yellowish or light brown colour. Check here
https://en.wikipedia.org/wiki/BeigeIt takes its name from French, where the word originally meant natural wool that has been neither bleached nor dyed, and hence also the color of natural wool.AE-9 doesn't have yellowish or brownish tinge... It's light gray-green when new.
Check FS chip at
http://www.e-paint.co.uk/Lab_values.asp?cRange=Federal%20Standard%20595&cRef=14449This chip isn't the closest FS equivalent, it's just what on my screen looks like new AE-9
HTH,
KL