Sodium street lamps and the light they emit

[AStaunton]

when looking at objects illuminated by sodium street lamps, I felt that they appeared somewhat different from what expected from my (somewhat naive) understanding of light. My knowledge is (and I'm talking only about visible light) that if something is red, and white light is shone upon it, this object absorbs all light from the white light that isn't red and reflects the red light and so the object appears red and similarly for any other colour. so for example taking the red object again, if we now shine blue light upon it, the red object absorbs this light and as this time there is not red light to reflect it simply appears black or as a silhouette.

so going back to the sodium street lamp, when I looked object illumanited by it, I could still kind of make out their colour, for example the green of hedges I think I could make out and the browney colour of the bark of trees...looking at cars, mostly their colour was very hard to determine and they did appear quite dark maybe even silhouette like with the exception of silver cars, they still looked very silver.

As the visible lines of sodium is predominantly a doublet of yellow lines (I think of around 500nm but maybe I'm wrong) I would expect anything that is not a colour of this wavelength to appear as a silhoutte, but as I said above this was not the case.

Appreciate any comments or suggestions about this. Thanks

 

[Antiphon]

High pressure sodium lamps emit a bit of a wide enough spectrum to distinguish some colors. Low pressure sodium light makes yellow look orange and every other color look black for the reason you described.