Hi First of all, I pologize first for not providing pics which may help in answering this question. Actually, this problem is two separate problems but with a similarity. 1) I occasionally scribble things on a black plastic/polymer table with my blue pen (blue because that's the ink color on a white paper). When I see those scribbles right under a white TL light (the table reflects the TL light) however, the scribbles look red. 2) Yesterday, I tried using an automatic blitz photograph machine (the one with you sitting on a chair over white background, instering coins and posing for several shots) while wearing a light blue shirt. When the photograph came out, my shirt turned pink. Any idea why the change in color from the blue to reddish? It's weird to me 0_0 Thanks.
My best guess for the writing on the table is that you are seeing an interference effect, similar to the rainbow color effect of a thin film of oil on water. Also, seen in the various colors you see on commertial optics anti reflection coatings. (most are blue, but some are green or red. An alternate explaination is some sort of floresence. Some dyes have a different color depending on whether the light is reflected or transmitted through the dye. Chlorophyl for example is green by reflection but a deep red by transmission. As for the shirt, I would suspect poor color control in the processing of the photo's.
another explaination for the pen is that ink is not made of one substance it is composed of 2 or more pigments to give the desired color and for permanance when dry. as you vary the angle of incidence the colors seen willalso vary
