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  • Writer's pictureTony Donnelly

Coloured Light Casts a Complementary Shadow

This experiment was to test the hypothesis that a coloured light casts a shadow of a complementary or opposing colour. The light source is from a sodium vapour street lamp which is usually perceived as being in the yellow spectrum.

I have laid out a large sheet of white and put some pages of differing colours on top.

The shadow colour, cast by a poppy flower, is affected by the different colour sheets on the ground but phenomenon of complementary shadow colour remains persistant inspite of the influence of the various coloured sheets.

Our perception of colour is a personal and subjective experience unique to each one of us, a relationship between the light source (street lamp), the subject (the poppy flower) that reflects/absorbs the light and the recipient of the reflected light (us).

The question is: why is the shadow of the poppy flower purple/blue when a shadow is just that, a shadow?

Why are the shadows in the photograph complementary or opposing, is it a quirk of our visual systems related to colour constancy of opposing colour theory ?

The camera which recorded the incident doesn't have an evolved brain that experiences colour subjectively, it is without the experiental prejudice of a lived or evolved life, stripped down. It is a box with a hole in front that focuses light on a sensor after all, is it giving a true representation of the scene?


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