BLACK & WHITE FILM

The determination of WWII tank camouflage colours is often based solely on the contrast of colours occurring in Black and White photographs. This contrast of colours depends on how the photograph was taken as well as the type of film. In this section some of the photographic methods in use in WWII will be described.

In order to describe these methods, photographs of British Flower class corvettes painted in the Western Approaches camouflage scheme will be studied. This type of camouflage consisted of light green and light blue geometrically shaped panels painted over a white basic colour (Figure 1). Within the limits of quality control, the colours were fixed, providing a good basis with which to judge black and white photographic methods.

Figure 1 Western Approaches camouflage scheme on the Corvette Montbretia. (Preston & Raven)

Photographed correctly, the Western Approaches camouflage appears light with reasonable contrast between the blue and green colours as shown in Figure 2. However this was not always the case. Significant misrepresentation of colours can occur due to the type of film used and or colour filters.

Figure 2 Correct contrast of colours in this photograph of the corvette Borage (Preston & Raven)

When B/W film was first developed it was sensitive to blue and ultraviolet light only giving an unnatural appearance to photographs. In 1873, the German chemist Vogel extended the sensitivity to include green light by adding certain types of dyes to the film. Although much improved, this type of film dubbed, Orthochromatic film, was still insensitive to the colour red. In this case red appears as a much darker colour than it really is. In an attempt to counteract the low sensitivity, red filters were used which unfortunately tended to darken greens and blues.

The effect of Orthochromatic film on the Western Approaches camouflage colours is shown in Figure 3. In this extreme case, the colours appear as a single dark grey colour without any contrast between the blue and green.

Figure 3 The corvette, Vetch, photographed with Orthochromatic film, presumably with a red filter, which has darkened the green and blue (Preston & Raven).

In the 1930s Panchromatic film became widely available. Panchromatic film has a dye that allows it to respond across the full spectrum of colours including red.

A popular belief is that green colours appear light in Panchromatic films. This is incorrect. The sensitivity to red of early panchromatic film was still not up to scratch leading to the widespread use of orange or even red filters. These filters darken blues and greens.

Furthermore, early Panchromatic films were generally purposely produced with a reduced sensitivity to green light to allow quality control inspection during manufacture. The extent of the reduced sensitivity can be judged by the fact that yellow or green filters were advised to obtain more natural looking tones.

Figure 4 The corvette, Lotus, photographed in September 1942 (Preston & Raven).

Figure 4 shows how the Western Approaches camouflage colours appear when photographed with an early type of Panchromatic film, which has been incorrectly filtered. The green is unnaturally dark, though the contrast of colours is much better than with the Orthochromatic film of Figure 3.

References

The photographs and drawings which appear in this article, were taken from the book “The Flower Class Corvettes” by Antony Preston and Alan Raven. The technical information regarding B/W film is from the website http://photography.miningco.com.