In a posting at the Fuku BBS A6M232 demonstrates the change in appearance caused by flash photography.
The photograph shows a piece of fabric from a Toryu (Ki-45) wing laid on a piece from a Type 97. A flash has been used for the picture on the left which makes the fabric look more blueish and the 97 surface more greenish. Without the flash the pieces are closer in appearance.
All illuminants, even various forms of daylight, will affect the appearance of colour. Most colorimeters require the illuminant to be set so the readings can be made against various forms of light and will therefore vary accordingly.
Image credit: A6M232 via Fuku BBS
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