A-20 Boston III colours

[thepureness]

Hi peeps, i'm about to start a free french A-20 Boston III (DB-7B) now I'm a little confused with the olive drab over neutral gray for these aircraft, I'm also seeing some painting references stating olive green which i just imagine is another name or OD.

In pictures I've seen the aircraft look green and not olive, anyone with any knowledge here would be helpful

[Graham Boak]

They were painted Olive Drab. There has been considerable discussion over the late war OD, whether it was really the later supposedly-common AN colour rather than the earlier USAAF OD 41, but American sources are quite definite that the AN paint was not used. There was however considerable differences existing within the label "OD", as little if any standardisation was applied after the US entered the war. For example, you can see C-47s with up to three different shades of OD on the same airframe because major parts were built by different subcontractors.

There are almost as many different shades offered by model paint manufacturers: I would look for one of the greener options.

Personally, admittedly without any hard backing, I feel that the browner shades of OD seem to have fallen out of use as the war progressed in favour of the greener shades. Whether this really was evidence for the use of the AN colour by manufacturers, or just chance, I'm certainly not qualified to judge.

[Nick Millman]

A lot of misperceptions arise from the substitution of FS 34087 for OD ANA 613 in Bulletin 157e of 1964. FS 34087 was quite different in appearance from ANA 613 but has been assumed to be identical. ANA 613 also changed slightly in composition from Bulletin 157d of 1959.

In January 1943, Major A.I. Totten Jr. of the Army Resources and Production Division proposed to consolidate the two shades of Olive Drab in use at the time, the USAAF dark Olive Drab 41 and the Army Ground Forces (AGF) Olive Drab, into a new colour Army/Navy (AN) 319, which was the same colour as the AGF Olive Drab. Major Totten's proposal was passed to the JAC Technical Sub-Committee on Camouflage by the Director of Military Requirements in February 1943 and approved by them in March 1943, prior to the promulgation of the ANA colours. Therefore the standards 319 in 3-1 Revised of April 1943 (for AGF) and 613 of ANA Bulletin 157 of September 1943 were supposed to be equivalents and have been reported as identical. The 1943 Bulletin 157 ANA 613 Olive Drab and Dark Olive Drab 41 are slightly different in appearance. The Munsell values reveal that although both of the same hue ANA 613 is slightly more towards YR (Yellow Red, e.g. more “brownish”) than OD 41 which is slightly closer to GY (Green Yellow, e.g. slightly more “greenish”) but the Value (lightness/darkness) and Chroma (saturation) are similar - ANA 613 being slightly lighter and less saturated than OD 41. But curiously their closest FS equivalents tend to reverse that impression.

An assertion often made is that paint to ANA 613 standard never actually replaced Dark Olive Drab 41. This is untrue. There are at least two officially documented references to the practical (not theoretical or 'intended') application of paint colours to that standard to USAAF aircraft late in the war. One of the reasons for the delay in introducing ANA 613 related to the reflectance requirements. The original Dark Olive Drab 41 was 7.8% but tests by Material Command Engineering Division at Eglin Field in June 1943 revealed that the new paint had a reflectivity of 9.4% which exceeded the recommended 8%. Various measures were then undertaken to reduce the reflectivity of ANA 613 before it was accepted for use as a standard. ANA 613 was eventually reduced to 7% which was the same reflectivity as MAP Dark Green. The slight change in appearance between the two colour standards was also related to the need to conserve Chromium Oxide.

The paint colour standard OD 41 is approximate to FS 33070 whereas the standard for ANA 613 is closer to FS 34086. The difference between the two is only 2.43 where 2.0 or less represents a close match. Taking into account the variance of actual applied paints to these standards and their degradation on an airframe the difference is academic and for practical modelling purposes can be safely ignored. The reason it became more brownish looking on some airframes was due to the constituent pigment interaction and weathering characteristics as the pigmentation was not mandated. I won't go into the variable chemistry of all that. The pigment specification was optional leaving manufacturers free to formulate their own paints to match the standard which was specified in both lacquer and dope formats. This resulted in paints which although matched to the appearance of the standard could and did age and weather very differently once applied to aeroplanes. This variance was officially recognised and somewhat surprisingly given the fuss over reflectance, ignored. Army FM 5-20H - Camouflage Materials and Manufacturing Techniques of July 1944 advised in Section 1. Paragraph 5, PAINTS. (e). ..."In spite of color standardization, there is considerable variation in hue between lots and between the products of different manufacturers."

Some idea of the "greenishness" of OD (as intended) can be gauged from the fact that it was authorised as a substitute for RAF Dark Green (a dark olive green or bronze green) and vice versa. British 'sister' firms were authorised to use RAF Dark Green in place of OD on US aircraft supplied in OD.

Anyone interested in the various underlying colour values of all the OD standards is welcome to send me a pm with their email address and I'll pass on a pdf on the subject 'The Development of USAAC/USAAF Olive Drab'.

Nick

[Mitch K]

This variance was officially recognised and somewhat surprisingly given the fuss over reflectance, ignored. Army FM 5-20H - Camouflage Materials and Manufacturing Techniques of July 1944 advised in Section 1. Paragraph 5, PAINTS. (e). ..."In spite of color standardization, there is considerable variation in hue between lots and between the products of different manufacturers."

Nick

Nick, as someone who has spent most of his working life wrestling with official standards and how they are interpretted in the "real world", and has a background in colours/dyes/stains, I found this fascinating. However, what do you think the section I've underlined means to individual modellers trying to built a specific airframe?

[Nick Millman]

Nick, as someone who has spent most of his working life wrestling with official standards and how they are interpretted in the "real world", and has a background in colours/dyes/stains, I found this fascinating. However, what do you think the section I've underlined means to individual modellers trying to built a specific airframe?

Don't sweat it I should think! There were 1,400 US paint manufacturers at work during WW2, although not all in the aviation industry, and even with their colour cards pinned to individual aircraft manufacturers at specific time periods (data for which is far from complete) variance in paint batches and degradation from different exposure and ageing factors would mean all bets were off as to precise colours on an operational airframe.

The bottom line is that each aircraft batch might be recognisably OD and yet each one 'different'.

Nick

[Mitch K]

Don't sweat it I should think! There were 1,400 US paint manufacturers at work during WW2, although not all in the aviation industry, and even with their colour cards pinned to individual aircraft manufacturers at specific time periods (data for which is far from complete) variance in paint batches and degradation from different exposure and ageing factors would mean all bets were off as to precise colours on an operational airframe.

The bottom line is that each aircraft batch might be recognisably OD and yet each one 'different'.

Nick

Which rather of course begs the question of why we tie ourselves in horrible knots arguing the toss about ultra-precise matching of shades Nick, I rather thought (and hoped!!!) that was what you might say, and it rather fits with the position I try to take. We cannot hope to authentically match the precise shade on a precise airframe at a specific time with the information we are going to have to hand.

Good topic, this. Lots to chew on!

[Nick Millman]

Which rather of course begs the question of why we tie ourselves in horrible knots arguing the toss about ultra-precise matching of shades Nick, I rather thought (and hoped!!!) that was what you might say, and it rather fits with the position I try to take. We cannot hope to authentically match the precise shade on a precise airframe at a specific time with the information we are going to have to hand.

Good topic, this. Lots to chew on!

Well, yes, but I think there is also a need to apply rigour when it comes to aircraft paint standards which are precise hues. The two aspects, the defined, precise paint colour standard and the variance of applied paints are frequently conflated, especially for OD. Understanding the essential character of the colour standard is a sound starting point in any exploration of paint colours but misperceptions abound, sometimes evolving from the popular use of specific hobby paints to represent them or from the use of modern FS equivalents eventually gravitating to be considered as the colour.

Nick

[Mitch K]

Well, yes, but I think there is also a need to apply rigour when it comes to aircraft paint standards which are precise hues. The two aspects, the defined, precise paint colour standard and the variance of applied paints are frequently conflated, especially for OD. Understanding the essential character of the colour standard is a sound starting point in any exploration of paint colours but misperceptions abound, sometimes evolving from the popular use of specific hobby paints to represent them or from the use of modern FS equivalents eventually gravitating to be considered as the colour.

Nick

Fair point. To all of this we can also add the (sometimes) limited understanding of the exact properties of the actual constituents present, and inter-batch variations therein. The difference in colour and behaviour of different portions of apparently (allegedly!) identical materials can be quite alarming in many cases!

And don't get me started on the "black art" of "aging" or "maturing" colourants before they are used...

[Steve in Ottawa]

Great info once again, Nick.

I like how you always take the care and time to present this kind of information in a 'formally informal' kind of fashion, without assuming that we know these resources to the same level as you do. You describe the underlying details and some of the science in a very readable and mostly-understandable way (it's great, but it sometimes reminds me of the blank stare I often had in school when the education was coming at me through a firehose. ) From these posts we can better understand why, for example, OD seems to shift colour so much, but you also acknowledge and accept that there are so many variables in play that shift the colours away from the ideal aim point... or paint.

[Nick Millman]

Great info once again, Nick.

I like how you always take the care and time to present this kind of information in a 'formally informal' kind of fashion, without assuming that we know these resources to the same level as you do. You describe the underlying details and some of the science in a very readable and mostly-understandable way (it's great, but it sometimes reminds me of the blank stare I often had in school when the education was coming at me through a firehose. ) From these posts we can better understand why, for example, OD seems to shift colour so much, but you also acknowledge and accept that there are so many variables in play that shift the colours away from the ideal aim point... or paint.

Thanks Steve

I'm glad it was of interest

Regards

Nick