Interpreting RAF colours from black and white photos

[rossm]

Definitely a provocative title but hopefully just an informative post and a request for the people who understand colour theory to comment on and allow me to improve my methods.

 

The following are photos of the colour chips in the RAF Museum book with various filters as used for black and white photography in order to show the possible problems in interpreting colours from photos. I haven't done a thorough evaluation yet of the differences.

 

Photos were taken outside in direct sunlight in RAW and converted using Lightroom, all with Daylight (5500K) White Balance and all the conversion sliders set to zero, hopefully aproximating to standard black and white film. I'm tempted to try the 'No Filter' shot with the yellow slider set to -100 but I'm not sure if this would emulate orthochromatic film or not.

 

One of my interests was Light Slate Grey versus Red for Coastal Command code letters and it's obvious that there can be effects from different filters.

 

Titles seem to have come up as links, sorry.

 

No Filter

 

P001 Yellow

 

25 Red

 

21 Orange

 

11 Yellow/Green

Edited March 25, 2017 by rossm
more detail on method

[FatFlyHalf]

A few questions.

What is standard black and white film? 

Orthochrome or panchromatic? 

Ilford or Kodak?

Film speed?

 

They all give slightly different results and the developing and printing processes adds yet another whole level of variables.  Then your comuter screen and mine are bound to be set up differently.........

 

Good luck with your project, I think that anything that helps reduce the guesswork will be useful.

[rossm]

52 minutes ago, FatFlyHalf said:

A few questions.

What is standard black and white film? 

Orthochrome or panchromatic? 

Ilford or Kodak?

Film speed?

 

They all give slightly different results and the developing and printing processes adds yet another whole level of variables.  Then your comuter screen and mine are bound to be set up differently.........

 

Good luck with your project, I think that anything that helps reduce the guesswork will be useful.

 

Standard black and white film to me is panchromatic and I'm not fussed about which one because it's not a project, more a way of saying that it's not possible to do any interpretation with any certainty because there are so many variables. What set me on the path was the number of Coastal Command aircraft in the 'white' scheme portrayed with Red code letters when Light Slate Grey was what was stated in the official documentation. I'm not necessarily against that interpretation as Red was a standard colour for codes for other commands, schemes, aircraft and may well appear in some colour photos (can't remember which though), but I wondered if there could be any confusion in interpreting b+w photos and my results seem to show LSG can be darker, the same, or lighter than the red of the roundel. So, in Paul Lucas article on Sunderland colours in MAM of January 2009, where he states in two photo captions that 'code letters appear to be Red' it could be so, but certainly isn't definite.

 

Maybe this whole idea is just a way of justifying using the colours I want to - but hopefully in a scientific way.

[Graham Boak]

If you use the period films and filters and printing processes then it can be termed a scientific study.  If you use modern films then you are introducing new variables that are different from the old ones, and there's no valid conclusions that can be drawn.

[bobmig]

To expand on what Graham said, this exercise won't really work the same with digital photography as it does with film photography. In manipulating a digital file you're introducing effects to an already existing image, whereas the use of filters, etc. in film photography alters the image that's actually captured. It also looks like there might be an exposure problem, as the charts look overall rather dark. Ideally you would want to take an exposure reading from an 18% grey card, and that would produce properly exposed swatches. With B&W film photography you wouldn't want to use filters on the camera, as they would then produce an inaccurate representation of the grey tones. For example a yellow filter would darken blue tones. FWIW, long ago, back when the Luftwaffe 02/71 scheme was proposed and scoffed at by many who thought ALL German 109Es were 70/71 (yes... there was such a time!), I ran a similar test. A friend had an original RLM colour chart which I borrowed and photographed in B&W. I don't remember the film I used... probably Kodak Tri-X. I metered from an 18% card, took a series of photos, processed the film and made prints, and lo and behold... the 02 tone matched that seen in many photographs. So I applaud the OP for his scientific curiosity and approach. It's just that you really have to go 'old school' for it to work properly.

Bob

[rossm]

Perhaps I haven't been clear about my aim, really to show that the use of filters, as would have been fairly normal practice back in the day, can distort the tones of different colours such that you cannot say with any certainty what a particular colour is, even compared with a known one in the same image, unless you know what filtration the photographer used. After that comes the type of film and how it was developed (high / low contrast etc.).

 

I can then use what colours I feel are right for any particular model based on both documentation and my personal interpretation of any photos.

 

I agree my shots look underexposed (the perils of rushing things) and the digital sensor won't match film responses but I hope that the comparison between colours with different filters shows that it is possible for the relative tones to alter with different filters. ie. Light Slate Grey can be lighter, darker or similar to Red depending on filter.

 

One day I might buy some film and try again but I think I'm happy with my conclusion above.

[hovering]

5 hours ago, rossm said:

such that you cannot say with any certainty what a particular colour is..

 

I can then use what colours I feel are right for any particular model based on both documentation and my personal interpretation of any photos.

 

Pretty much

 

Actually, is it possible to use the photo technology/techniques of the day to take photos of the BBMF Lancaster and see how it looks?

 

Edited March 25, 2017 by hovering
extra thoughts!

[PFlint]

one other thing the others might not be considering...

if viewing this on a modern HD computer monitor it's capable of a degree of brightness that was impossible in the 1940's

 

filters were used in the 40's - they were for anti-glare purposes and were available in red or green

 

if you really want to start a war start a new topic "Interpreting Soviet WWII colors from black-and-white photos"

that will surely light a raging bonfire

[bobmig]

The most common filter used in B&W film photography was a medium yellow. It was intended to restore blue skies to a more realistic appearance. Sky tends to photograph lighter than it appears to the human eye because of the light blue colour and the ultraviolet radiation it contains. The yellow filter darkens it a bit and brings it back to a more 'normal' tone. Once again I'll reiterate... we're talking about black & white film photography here. The only filter that will reduce glare - and it depends on the type and direction of the light - is a polarizing filter, and I'm not sure they were available at the time. In any event, it wouldn't affect the rendition of the colours. I suppose we're drifting off topic here!  I'll shut up now!

Bob

[bobsyouruncle]

There are so many variables with the light and shadows when looking at objects in photographs.

I came across this 'illusion' about a year or so ago, when discussing F-15C camouflage colours with a decal manufacturer.

It's good for showing the effects of surrounding colours on the colour you're trying to pinpoint.

I didn't believe it was the same shade until I cut a square of colour from one area and physically moved it onto the other one.

https://en.wikipedia.org/wiki/Checker_shadow_illusion

[rossm]

Some more thoughts and comments on the method - I used a 1980s lens and filters from the 1980s in front of the lens for the shots so no digital manipulation, Lightroom settings were the same for each shot and intended to be as 'neutral' as possible. However the one step I have no control over is the de-mosaicing of the RAW file and given most sensors have twice as many green pixels as red or blue there is a definite unknown there. Wonder if a Fuji X-Trans or Sigma Foveon sensor would have given different results? Hopefully not.

 

Not sure which filters were most common in the day, nor what they would be made of (gelatin?). Ansel Adams used to use a Wratten No.12 as 'minus blue' which is a deep yellow going on orange.

 

Anyway, definitely to be repeated with film one day, and, given the 'checker effect' just mentioned, possibly with paints brushed next to each other with no intervening white or other colours.

 

One example which got me thinking of this was in 'Man is not Lost', the autobiography of Group Captain 'Dickie' Richardson, where there are photos of Whitleys BD572 - YG.R and BD569 - YG.H. 'R' has codes and serials which are a close match for the red of the roundel and fin flash and which are darker than the uppersurface camouflage which would include Dark Slate Grey - so my conclusion is that they were Red. The background of the photo is obviously haze and is not dissimilar in tone to the White of the lower surfaces so probably no filtration was used. The photo of 'H' has a great deal of contrast between sky and cloud - often a result of using a filter, probably red or orange (possibly yellow) as the grass looks dark and the serial and red portions of the roundel and fin flash look much lighter that in the photo of 'R'. Again the serial would seem to match Red but the code letter is darker - so could be Light Slate Grey if the filter was red (based on my trial shots).

Edited March 26, 2017 by rossm

[GordonM]

Having worked in the photographic trade I sold at one point lots of vintage collectable equipment and accessories. Much of the 'serious' 35mm equipment was German, mainly Leica and Contax, however there were also British copies around. However filters were almost a 'de facto' fit to many cameras, even those used by what might now be termed 'happy snappers' lots of the filters were what used to be known as 'series fit' these were generally push on and would fit appropriate size diameter lenses. The UV/Skylight filters were uncommon pre and during the war, most photographers used a pale yellow, sometimes known as a straw filter as their standard filter. As mentioned in the US Kodak supplied Wratten filter gels, originally for the movie industry, which could be trapped in a holder and fitted to still cameras too. Unlike the 70's until the pre digital age when companies like Hoya took over and restricted the colours commonly available, the 30's, 40's and even into the 50's saw massive variation in shades available. Yellows filters ran from straw, light yellow, what became the standard 'yellow' through to quite dark colours. Again red had many variations and green was commonly used as it gave better tonal renditioning for foliage in landscapes. 

We've become used to filters being consistent and a much more restricted choice, for those who even now still use film, but in the past things were much more complicated and while tests show the effects well, without a great deal of caution don't aid interpretation a great deal in my opinion.

[rossm]

4 hours ago, GordonM said:

Having worked in the photographic trade I sold at one point lots of vintage collectable equipment and accessories. Much of the 'serious' 35mm equipment was German, mainly Leica and Contax, however there were also British copies around. However filters were almost a 'de facto' fit to many cameras, even those used by what might now be termed 'happy snappers' lots of the filters were what used to be known as 'series fit' these were generally push on and would fit appropriate size diameter lenses. The UV/Skylight filters were uncommon pre and during the war, most photographers used a pale yellow, sometimes known as a straw filter as their standard filter. As mentioned in the US Kodak supplied Wratten filter gels, originally for the movie industry, which could be trapped in a holder and fitted to still cameras too. Unlike the 70's until the pre digital age when companies like Hoya took over and restricted the colours commonly available, the 30's, 40's and even into the 50's saw massive variation in shades available. Yellows filters ran from straw, light yellow, what became the standard 'yellow' through to quite dark colours. Again red had many variations and green was commonly used as it gave better tonal renditioning for foliage in landscapes. 

We've become used to filters being consistent and a much more restricted choice, for those who even now still use film, but in the past things were much more complicated and while tests show the effects well, without a great deal of caution don't aid interpretation a great deal in my opinion.

 

Useful to know about the range of colours - I came in at the end of the 70s and only remember the Hoya and Cokin/SRB types.

 

I also agree about the caution - I've certainly convinced myself it's possible to swap the relative lightness of Red and Light Slate Grey with different filters and it's rarely easy to tell what, if anything, was used in the original photos of the time. I'm beginning to think most interpretations until recently, when someone on here raised a caution about filters, have ignored the possibility - I know I didn't think of it when studying black and white photos in the past.

 

I think my aim is to make myself more sceptical about the existing interpretations and to make my own mind up whenever possible. 

 

Also to make people more accepting of alternative interpretations, not usually a problem here but I have seen the 'cannot possibly be' kind of statement around t'interweb

Edited March 30, 2017 by rossm
Added last sentence

[Patrick Martin]

Remember when you go to a museum and look at an object, your eyes are making an impression in your mind of what you see.  It is of reflected light - colour, or black and white.  Same when you look at a printed sheet - magazine, book etc. - reflected light and all these steps can be seen in different conditions.  Condition of subject comes to play - sun (angle etc), weather, dust, where on the planet you are viewing, altitude, I could go on .... Trust a repainted real subject after 50 years?

  The moment you take a photo (a camera's interpretation) then scan (scanners interpretation) and then display the result in print (yet another interpretation) and then viewed by eyes (yet yet another interpretation).  By this point it is a copy of a copy of a copy that is being viewed. 

  BUT if you project a result on a screen (after at least one interpretation and maybe photoshop alteration or two) - then it is projected light - entirely different kettle of fish. 

  Nothing replaces holding up your painted result to an original painted aircraft (don't get me started on scale colour here). 

  The bottom line will always be - does it look right to the viewer.  How many UK modellers think, this or that, colour used on roundels are wrong on decals?  And yes they are - why you ask.  Because everything is an interpretation of an interp...........

 

Pat Martin

 

[Black Knight]

Another aspect to take into consideration is that most lenses pre-WW2 were not coated.

Since the 1950 lenses have first been single coated, then double coated then multi-coated. These coatings affect both the rendition of colours on b&w film but also the nodal focus of the colour.

A lens from the late 1960s onwards doesn't have the same qualities of a 1930s lens

[Juanita]

Thanks for your work RossM. It's really nice to see this comparison.

Although it can't be used as a direct guide to colour interpretation of b/w photos, it certainly highlights the traps of try to identify colour only from shades of grey.

 

I was very surprised by the red/light slate grey comparison with the red filter. I was recently working on a Whitley...YG-H as it happens (would love the see the photo you refer to, RossM)...and I took the official specs (grey codes) over the apparent 'colours' visible (red) in the photo of YG-R but it felt counter intuitive.

 

Your tests will be handy for at least being able to say, 'could it be this colour'.

 

Thanks GordonM for your insight. My father, back in the old days, used a red filter to make the clouds/sky look interesting. This made me appreciate how much filters were just a part of standard B/W photography practice.

Juanita

[Antti_K]

A very interesting topic!

 

Filters were (and are) used for two primary reasons:

1. To minimize the effect of Haze (those tiny particles in the air which are smaller than air molecules and reflect "back scattered light" causing too bluish picture). In these cases the filter should be yellow.

2. To correct colours for printing. For example if you want to show a very dark sky with white clouds then you should use a deep red filter with panchromatic B+W film.

 

Third reason is anti-vignetting but I don't know if this has been used in "consumer" cameras. The only times I have used an anti-vignetting filter is during aerial reconnaissance and survey missions.

 

I would firstly try to recognize what film type was used. Take a look at the RAF Roundel; if the red center portion looks darker in the photo than the blue ring then the picture was taken using orthochrome film. Another hint are the camouflage colours; they look almost the same when photographed wit orthochrome film. If the blue and red look similar then panchromatic film without filter was used.

 

One thing to remember when taking pictures with a DSLR: digital camera has a different sensitivity than film. You need to use a UV filter with digital cameras but not with film. Reason: films are not sensitive to UV light. This means that a digital B+W photo will look different in any case when compared to film. It is also useless to scan photos from books and then "tune" them using Photoshop or Lightroom. Fun it may very well be but not "scientific".

 

Best Regards,

Antti

[rossm]

10 hours ago, Antti_K said:

 

Filters were (and are) used for two primary reasons:

1. To minimize the effect of Haze (those tiny particles in the air which are smaller than air molecules and reflect "back scattered light" causing too bluish picture). In these cases the filter should be yellow.

2. To correct colours for printing. For example if you want to show a very dark sky with white clouds then you should use a deep red filter with panchromatic B+W film.

 

 

I'm also starting to wonder if there is another possibility - with early films intended to be panchromatic was the response to different colours uneven and would a professional photographer have used filters to try to correct that? I'm thinking 1930s going into early 40s.

[Black Knight]

yes; Kodak film reacted differently to Ilford which reacted differently to Agfa, and that to Perutz, and that to GAF

Each of these companies used to issue a table of suggested filters to use to get a standard 18% reflective grey scale; the tables were commonly used by professional and serious amateur photographers only.

Even films within a maker reacted differently; Kodak Verichrome would react differently to Super XX

[Black Knight]

Another thing that would influence how the film reacts is how fresh the film was.

I know you lot would not know, but film ripens as it ages. It reaches a certain point where it is over ripe. Amateur film was designed to ripen over about a year as thats how long a film would be in a camera - a birthday at the start and the end of a film. Professional film was ripe about 1 month after production and was to be used within a month of that date.

Professional photographers always kept their film in a fridge to slow the ripening down. Some even kept it in a freezer

[rossm]

24 minutes ago, Black Knight said:

yes; Kodak film reacted differently to Ilford which reacted differently to Agfa, and that to Perutz, and that to GAF

Each of these companies used to issue a table of suggested filters to use to get a standard 18% reflective grey scale; the tables were commonly used by professional and serious amateur photographers only.

Even films within a maker reacted differently; Kodak Verichrome would react differently to Super XX

 

'Twould be interesting if you had an example table.

[Antti_K]

25 minutes ago, Black Knight said:

Professional photographers always kept their film in a fridge to slow the ripening down. Some even kept it in a freezer

 

Indeed; we kept all our films for aerial recce or survey work in a freezer at -18 centigrades. One day before the mission the film was moved to a fridge.Then the film containers were wrapped in a chamois and placed in a bag to keep them cool.  I still keep my films for SLR photography in a freezer / fridge.

 

It is also important to process an exposed film as soon as possible. Otherwise it is necessary to put it back to the freezer, but you can only buy some days that way. Looking back I remember my grandparents who had one roll in the camera for years; they didn't want to waste that precious film. As it was Agfa colour negative film the prints were always completely red

 

BR,

Antti

[Black Knight]

Just about all my photographic literature was dumped about 15 years ago

[Antti_K]

23 minutes ago, Black Knight said:

Just about all my photographic literature was dumped about 15 years ago

 

Ouch! That's sad. I think that 30-35 years ago the photography books still gave you the theory in depth. Today people get easily bored if they need to study a few formulas or look at a page without pictures.

 

I bought Langford's excellent books a couple of years ago from a book shop in Uppsala, Sweden. Then there is some very good theory books published by the U.S. Navy and they are also available online. Then of course I still have my study books about aerial photography (written by former 543 Squadron navigators and photographers).

 

BR,

Antti

[Black Knight]

My father was a happy snapper, then a professional, then I was, so I had papers from the late 1930s

Due to circumstances I had to leave all that behind in a storage shed and I only got a few thousand negatives back - I think all the rest was dumped