I remember learning about color temperatures and photons (the smallest measurable light particle) and magnetic radiations wave length in physic class and being mesmerised; there were invisible forces in action, after all photons were much better than god, they did not go by the book but rather by the agreement between my eyes and cosmic energy (I love those two words Cosmic Energy; if your tongue slip, they make Comic Orgy, or some other fun pun like Come to my Carnegie). In the olden days, it was very important for a commercial photographer to be able to gage or measure different light radiation and transparencies were always discussed in terms of Hot or Cold. Every studio had rolled sheets of colored gelatins to correct and change the output of the light source being used. Some photographers used a colorimeter, a scary little piece of equipment which made me sweat a few times as I was completely incapable of using one and dreaded being asked to make use of one, I became very good at gaging the light temperature with my naked eye. Not with the precision of a colorimeter of course but near enough to always get the right gelatin. I always assumed that, coupled with my large smile, my skill would pass me as a good assistant. Unfortunately, commercial photographers have always been very needy little people who expect an exact light reading of their Mona Lisa. I was forgiven for being a girl but later dismissed. I went on to work on my own and shot lots of polaroids which I loved because they were always too hot or too cold. A bit like me.
This is a bygone era.
(I love those words Bygone Era...)