# Stupid color question **URL:** \ **Category:** Factual Questions\ **Created:** [December 16, 2006, 3:55pm UTC](https://boards.straightdope.com/t/stupid-color-question/384402 "2006-12-16T15:55:36Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![Sapo](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@Sapo](https://boards.straightdope.com/u/Sapo)\ **Post date:** [December 19, 2006, 4:29pm UTC](https://boards.straightdope.com/t/stupid-color-question/384402/21 "2006-12-19T16:29:38Z")
**Nava** , is the colour of that bond so because it blocks all light and only lets through that colour. Or is it because it absorbs that colour, has a change and then spits out a photon of the right wavelength? (isn’t that last one phosphorescense? sp? or is it fluorescense?) ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [December 19, 2006, 4:30pm UTC](https://boards.straightdope.com/t/stupid-color-question/384402/22 "2006-12-19T16:30:15Z")
This is extremely fascinating. As an artist, I love colour, and I enjoy physics and chemistry too. I just checked the Toronto Public Library for Nassau’s book, but they only have it in the reference stacks, so I can’t actually borrow it. Bother. So a dye is molecules that spread through the thing being dyed, and a pigment is little coloured chunks that cover the thing being pigmented, and are held on by a binder (basically, transparent glue)? ---
**Author:** ![Dinsdale](https://avatars.discourse-cdn.com/v4/letter/d/97f17d/32.png) [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)\ **Post date:** [December 19, 2006, 4:40pm UTC](https://boards.straightdope.com/t/stupid-color-question/384402/23 "2006-12-19T16:40:39Z")
Gee - thanks guys! Kinda jammed up here at work today and tomorrow, but I definitely have some stuff to think in my free time. ---
**Author:** ![Hypno-Toad](https://avatars.discourse-cdn.com/v4/letter/h/b2d939/32.png) [@Hypno-Toad](https://boards.straightdope.com/u/Hypno-Toad)\ **Post date:** [December 19, 2006, 8:54pm UTC](https://boards.straightdope.com/t/stupid-color-question/384402/24 "2006-12-19T20:54:14Z")
This may be a book for all you dyed in the wool color fans:[“The Perfect Red: Empire, Espionage and the Quest For the Color of Desire”](http://www.amazon.com/Perfect-Red-Empire-Espionage-Desire/dp/0060522755/sr=8-1/qid=1166561403/ref=sr_1_1/103-3931537-4040616?ie=UTF8&s=books) A very interesting book about the struggle to find a superior red dye and the effect of the discovery of Cochineal dye in Central America. ---
**Author:** ![Nava](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@Nava](https://boards.straightdope.com/u/Nava)\ **Post date:** [December 20, 2006, 10:56am UTC](https://boards.straightdope.com/t/stupid-color-question/384402/25 "2006-12-20T10:56:36Z")
[QUOTE=Sapo] **Nava** , is the colour of that bond so because it blocks all light and only lets through that colour. Or is it because it absorbs that colour, has a change and then spits out a photon of the right wavelength? (isn’t that last one phosphorescense? sp? or is it fluorescense?) [/QUOTE] The color “of” a bond/substance is the color it would absorb and return. If the return does not involve chemical changes but does require a long time, then you get phosphorescence. If it doesn’t take a long time, you just see the object in that color. Note that when it comes to color absorption we’re talking all the time of “light as particle”; “light as wave” is useful for other stuff (like “why do some objects shine when struck by light but others don’t?”) Hint: I learned which one was phosphorescence and which fluorescence by remembering that the tubes in the kitchen are fluorescent. Fluorescence is the emmision of light by electrically-excited gas at low pressure. [Previous page](https://boards.straightdope.com/t/stupid-color-question/384402.md?page=1)