WW2 Olive Drab

OD Based on Yellow

Alfred Palmer made 4x5 Kodachrome transparencies for the Office of War Information in 1942, creating beatifull images. These images were shot in the United States, and in contrast to the published pictures taken abroad, have excellent color accuracy. This makes it possible to accurately determine the 1942 OD color. See the next picture with the red square from which the color is averaged and sampled.

The sampled area does have on average an RGB value of: (37, 37, 21), and an HSV value of (60, 43, 15). The color wheel below of the average value shows it can be specified as yellow mixed with matt black. This partly matches the Olive Drab specification of simply being a mix between black and yellow according to (2). (1) however states black and ochre is used for OD, while ochre is more of a reddish color than yellow.

To give an example, below what happens when yellow is mixed gradually with black:

100% yellow	50% yellow	25% yellow	12.5% yellow

It has to be noted though, that this results in an 100% saturated color: the HSV value of the right sample is (60, 100, 13), and slightly differs from the sample taken from the picture, which has an HSV value of (60, 43, 15).
The following example color photograph from Palmer, shows this difference in saturation. This causes the green to be more dull, a bit more in the blue area. Here the OD color appears to be a bit lighter as well, which may have been caused by dust (see for instance the color variation on the bumper of the nearest truck).

OD Based on Red

Other images of Palmer, show however a significantly different OD color, which does not appear to originate from yellow as described above. The picture below is an example of a Stuart which, apart from the mud, does have a brownish appearance in the sampled area.

The average RGB value of the sampled area is (37, 22, 20), and the HSV value equals: (7,46,15). The colorwheel representation of this color points into the direction of a red origin of this OD version. This sample shows the more opposite side of ochre, being more in the reddish area:

OD Based on Blue

Last example is an image of a halftrack painted in significantly different color, much more into the blue area. This difference can be seen clearly when comparing the helmet color of the soldier in front, which has the same color as the halftrack, with the soldier's uniform, which is more or less going towards the OD color based on yellow as described above. Maybe this paint was not used by the army, but marines or airforce.

The color sampled here has an RGB value of (47, 56, 68), and an HSV value of (180, 6, 13):

Conclusion

The sampled pictures show that Olive Drab, as used in the Us Army during the second word war, can be defined as a yellow to red base color, mixed with black. The official specification of Olive Drab during this period being either yellow or ochre mixed with black, does match the analysed pictures. Safe bet would be using the OD paint color based on yellow for accurate military models.