RAF Sky Grey

[Beard]

I've just got my hands on Xtradecals BoB 75th Anniversary Spitfire part 2 and there are a couple of 41 Squadron aircraft that the instruction sheet suggests were painted Sky Grey on the undersides.

Sky Grey isn't a colour I've come across before and a Google search didn't bring any answers so I had a look in my copy of British Aviation Colours of WW2 and it appears to be a lighter shade than Medium Sea Grey.

Anyway, I have two questions:

1) I've never heard of RAF fighters painted in this colour before, I'm aware of the discussion about Sky, Duck Egg Blue, etc. but there aren't any Air Ministry Orders (that I can find) about this. Is this possibly to do with the confusion of the time?

2) Can anyone suggest a good match? (Preferably in Humbrol enamel, I'm too lazy to mix paints.)

Thanks, in advance,

Simon

Edited July 27, 2015 by Beard

[Graham Boak]

Colourcoats do a Sky Grey. It was not official for any RAF scheme, but was identified as an undersurface colour on two wreck digs. Neil Robinson did tell me that the Spitfire tailwheels they found were all in Sky Grey, but Edgar suggested that this was (or could be) a Supermarine primer.

Edited July 27, 2015 by Graham Boak

[Beard]

Thank you Graham.

So it may be a case of painting with whatever came to hand, at squadron level, following the order to paint undersurfaces of fighters in 'Sky'.

Edited July 27, 2015 by Beard

[Graham Boak]

Possibly. It is a working assumption anyway. Perhaps one day someone could revisit the relics and come up with a different interpretation - or a confirmatory one.

[Beard]

'Possibly' is good enough for me. Occam's Razor comes in to play here.

Now all I have to do is get my hands on some Colourcoats in the model shop desert in which I live. Alternatively, I'll be taking my copy of British Aviation Colours to my local Humbrol stockist on my day off.

[lasermonkey]

Reading the Lucas BoB book the other day, he mentions that two unidentified spitfire elevators were found with Sky Grey on the undersides. Both were starboard.

It's a shame the a/c identities aren't known.

[Edgar]

In July 1939, a memo was issued, listing, with their vocabulary numbers, all the paints that could be used, and the surfaces on which they could be used. Sky Grey had no vocabulary numbers, so should not have been capable of being ordered, much less stocked.

Edited July 27, 2015 by Edgar

[Troy Smith]

'Possibly' is good enough for me. Occam's Razor comes in to play here.

Now all I have to do is get my hands on some Colourcoats in the model shop desert in which I live. Alternatively, I'll be taking my copy of British Aviation Colours to my local Humbrol stockist on my day off.

Hi Simon

It's a complex subject, with many variables.

One point, what are the serials?

this is sheet in question

http://www.hannants.co.uk/product/X48145

41 Sq plane.

No serial known. Tony O Toole helped with some of these sheets and he may be able to shed more light on this.

EDIT - listed on Asisbis as N3126

http://www.asisbiz.com/il2/Spitfire/MkI-RAF-41Sqn-EB-L-Shipman.html

pic

Looking at the Xtradecal instructions there is note of the panel under the nose.

If this is the reference photo I'd suggest this is more likely still with the Black/White undersurface scheme still, note the very light colour of gear leg and side of radiator.

Also of note is the visible repainting of the fuselage roundel back to 35 inch, note plane in background has an oversize roundel from the addition of an equal width ring to the existing roundel.

Regarding Lucas, here's the relevant bit from "Britain Alone" and is what the various other paint matches are based upon.

But, this thread covers a lot of the main points raised over the use other paints instead or Sky, or local mixes.

http://www.britmodeller.com/forums/index.php?/topic/234966713-spitfire-mk1-with-extra-dark-sea-grey-belly/

But here's the edited version. Much of this is about Eau De Nil, another colour identified above.

I don't have the Lucas book to hand, but IIRC the main evidence was from wreck parts, matched to colour chips, by eye, unfortunately no photos of this are shown. I con't remember what the colours were matched to, possibly FS595?

Also, we are dealing with parts from mostly buried wrecks, and soil chemistry and just ageing of the paint can change apparent colour, for example paint binders can yellow with age, causing the colour to shift and darken in appearance.

In the case of Sky paint, that would cause a darkening and greening of the apparent colour.

It is possible to analyse the paint to find out the pigments and binders etc, but a visual comparison with paint chips is of limited use.

The above is trying to put simply what Nick Millman has written about, at length, here and on his blogs, and any errors in the above are mine, not his!

I mention Nick as he is a very through and careful researcher on the subject of paint and colour

Varitions in the Sky have been noted since the time of introuduction, This is discussed in the Ducimus Camouflage and Markings series, in particular in the Spitfire volume, which was written in about 1970, but makes many valuable points as reasons for variations.

What has happened since the Lucas book is that profiles in the book have had a variety of underside colours given to them , Eau De Nil, Sky Grey, Sky Blue, and this has lodged in modeller and decal manufacturers brains as a 'fact'.

That said the use of Sky Blue instead of Sky seems to be more widespread than was thought when the Ducimus was published. There have been thread on this here.

Without professional analysis of the wreck parts, and that would only tell you what those specific aircraft were painted in, you are into the realm of a 'best guess'

The 'best guess' can be improved upon by finding out when the plane entered service and from photos of non-standard underside demarcations, eg as seen on some 85 sq and 17 Sq Hurricanes in June 1940, implying an infield repaint, for an example of elimination of unlikely airframes, see the quoted Spitfires above.

From a modeller's point, it's only really aircraft that are in this 'window' that are candidates for having non-standard underside colours. They certainly make for more visually appealing models.

I'm not claiming any special knowledge of the subject, more adding a basic summary for the less obsessed who may be intrigued by the thread title, and confused by some of the comments.

There was one interesting (at least to me) point within Paul Lucas's book. The three undersides identified from wreck sites as being Eau de Nil came from the units that were at Linton-on-Ouse and one other Humberside base (Kirton-in-Lindsay?) when the order came through. To me, this suggests a very local use of whatever colour it was, whereas Paul seems to have extrapolated this to a wider range of units coming from different parts of the UK. In this he could be said to have been supported by MJF Bowyer, based on personal observation at the time by his acquaintances and himself, that Sky as in use in 1940 was distinctly greener than that seen later in the war.

I entirely agree that Eau-de-Nil was in fairly wide use prewar, within the RAF and indeed domestically. But the paint applied to aircraft will have come from the limited range of colours available to the correct DTD specification, and those did not (to my knowledge) include Eau-de-Nil. I have wondered if it was the identity of the lighter green sometimes spoken of as in use for some aircraft interiors.

In his excellent book, Paul does pretty thoroughly discuss the problems of supplying Sky at this time, and the potential solutions/problems. Nick Millman has also contributed to the subject, elsewhere on this site.

The issue of No16 EdN and No1 Sky Blue to the correct DTD standard for application to both fabric and metal exterior surfaces is a point I have raised many times. If EdN *did* exist in this form it was most likely a civillian order for the colour.

I don't have my copy of Lucas immediately to hand but I do recall that there are photos (inside one of the covers?) of researchers holding a FS595 fandeck against their chosen specimen parts, rather than a copy of the chips from BS381(1930).

I’m also fairly certain that PL didn’t say that these colours *were* EdN and 1 Sky Blue, just that they looked like them. The certainty has been applied retrospectively by others.

Sky is essentially white with a couple of strong pigments added to get the required final colour. Varying the proportions of these pigments even slightly can have a distinct effect on the final observed colour. I've long been of the opinion that this is a more likely source of the variations observed in 1941 (and indeed later) than the use of non-standard colours.

For the record I doubt the widespread use of Air Ministry Sky Blue for the same reason.

John

I agree and FWIW (I've mentioned it before) I've recreated colours close to both BSi standard colours using similar pigments to the white, yellow and blue paints that would have been held in stores. The use of yellow instead of yellow ochre makes a significant difference to the resultant hue and recreates the stronger blue-green appearance.

The "old" cheap recipe for Eau de Nil, in use as late as 1929, was Zinc Oxide (white) and Pale Chrome Green. The zinc oxide has a rather poor tinting strength and a tendency towards yellow or creamish. The chrome green is interesting because it is made from chrome yellow and Prussian blue pigments. The chrome yellow decomposes the blue pigment over time making the appearance browner, exacerbated by yellowing of the binder. On the Lucas examples genuine Eau de Nil would have shifted towards more yellowish. But they looked to me like typical "sky blue" paints where age darkening and yellowing of the binder had made them look more turquoise or greenish than they probably were originally.

I thought this the case when I looked at the chip in the 1930 standard for BS 381 # 1 Sky Blue but very usefully the original book includes a sample of the clear celluloid used for the swatches so the extent of browning can be gauged reasonably accurately. The original colour was undoubtedly more turquoise (greenish) than the colour one usually associates with sky blue but the complication is that clearer sky blues and blue-greys shift towards a similar appearance with the yellowing of their binders. This is why the French Gris Bleu Clair is now thought by some to have had a more blue-green appearance than it really did, because they are assessing it from extant but aged paint surfaces. The shifts can occur without the surface appearing in any way degraded, even retaining its gloss, which can be misleading because the assumption is that the paint is "as good as new".

Nick

The Lucas book does list where the parts are, which is several small museums in Sussex and Kent, which are listed but no photos, and no history of the where the parts are from.

I'd go round these places if I had a car, I'm not dedicated to try to get to them by public transport, but as the research was done maybe 15 years ago the paint may shifted more anyway.

If you could get actual samples you could analyse them, and that would yield more information, but would you even be able to get samples?

I would suggest that aircraft built after the introduction of Sky in June 1940 are probably going to have the specified paint as factories would get the right paint as a priority?

and in the case of Spitfires this can be pinned down if you have a serial.

see http://www.airhistory.org.uk/spitfire/production.html

From this I'd suggest all the Castle Bromwich and the Supermarine somewhere on this page

http://www.airhistory.org.uk/spitfire/p010.html are likely to have factory applied Sky.

Unfortunately there is not similar page of Hurricane production.

[Beard]

Thank you, Edgar And Troy.

Edgar's point would suggest that, if Sky Grey was used, it was either old stock or was an interpretation of 'Sky'.

Troy, to summerise your post. It could be variations in paint (mixed locally rather than at factories), degredation of paint over time due to being buried or, the interpretation of B&W photos.

I know of two local museums that have parts of crashed aircraft, one easily accessible by public transport, but I doubt either of them would let anyone take paint samples (and that's not even taking into account my inherent lazyness and lack of access to a lab to analyse samples).

So, based on the evidence we have, I think it's fair to say that we don't know for certain and will never know.

I'll paint the underside of my model in a lightish shade of Sky.

Thanks to everyone who's taken the time to contribute.

Simon

[Giorgio N]

In July 1939, a memo was issued, listing, with their vocabulary numbers, all the paints that could be used, and the surfaces on which they could be used. Sky Grey had no vocabulary numbers, so should not have been capable of being ordered, much less stocked.

Edgar, in Eyes for the Phoenix there's a 1944 store reference of 33B/295 for Sky Grey. If this was not present in 1939, do you know when this introduced ?

[Andrew Jones]

Sky Grey was a standard Fleet Air Arm colour for the early war years , used as an undersurface colour on Fulmars , Skuas , Swordfish and others. It's quite possible that paint from FAA sources could have been used to apply "Sky" undersurfaces on some RAF aircraft , although I have no proof of that,

Andrew

[Graham Boak]

Lucas's BoB book has a table of Vocabulary of Stores reference 33B/xxx. Sky Grey is in there with the numbers 263-265, adjacent to Sky Blue with numbers 266-268, these two being the last colours presented for DTD308 i.e. the prewar matt cellulose paints. The different numbers for each paint apply to different sizes of can. They are then followed by a string of familiar colour names for DTD314 i.e. Synthetic paint. Here Sky Grey is 287-289, but is also quoted as 293-295 for DTD 83A. Sky itself does not appear until 330-338, covering DTD 308, 83A and 314.

So Sky Grey was available before Sky itself, and could have been provided if asked for, or provided as a result of misunderstanding.

This system was common to the RAF and the FAA. Whether this was true for the actual storage of paint is another matter, leaving the ready availability still uncertain.

[tempestfan]

Sky Grey was a standard Fleet Air Arm colour for the early war years , used as an undersurface colour on Fulmars , Skuas , Swordfish and others. It's quite possible that paint from FAA sources could have been used to apply "Sky" undersurfaces on some RAF aircraft , although I have no proof of that,

Andrew

I was thinking along similar lines - were any FAA and Fighter Cd squadrons co-based or at least close together ?

Was there any "official" (stipulated in directives) use of Sky Grey in the RAF ?

[Graham Boak]

Sky Grey is not called for in any RAF camouflage scheme.

[Mike Starmer]

This might spanner the works a little but the Spitfire tailwheel struts that PL says that were close to Sky Grey may have actually have been BS.381 No.30 French Grey since that was the colour of pre-war Walrus aircraft as Supermarine Seaplane Grey and the prototype Spifire at one time. The colours are not disimilar.