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Originally Posted by GDJMSP A small point about black backgrounds for pics. Yes - it works very well. I particularly like it for photographing gold. But contrary to what many think - black reflects more light than white does. Sounds odd I know - but it's true. And it is often why just about any object photographed against a black background turns out so well. |
Sorry GD, it is very rare that I don't agree with you, but my paychecks come from my company (
www.xrite.com) that manufactures instruments that measure and control color in a phases of manufacturing and color consistency.
These instruments are used in everything from matching paint at Home Depot, Loews and Ace, consistent color printing, to auto body shops where you want to make sure the color of your three-year old car has the same color from front panel to back (ever wonder how body shops match the paint perfectly?). Another example,
Coca Cola owns the
red color of their Coke, and use our instruments in manufacturing to make sure their red is well...
THEIR red !
Natural or white light contains ALL of the visble light frequencies that you would see in a rainbow or prism (Issac Newton discovered this). Black from a color science application is sceintifically absent of color. That is, light energy from the sun or your home light is emitted and no frequency of color (sensation of color) is reflected from the black surface.
This is why you see football teams like the Dolphins force opponents like the
Oakland Raiders to wear
black jerseys in South Florida facing the afternoon sun. The Raiders, wearing black, are not reflecting any light energy and consequently since the energy of the sun is totally being absorbed, the Raiders are playing at higher temperatures than the Dolphins dressed in their white "home" jerseys. Hence the home field advantage.
The visible light spectrum is small, 380 nanometers to around 700 nanometes whereby the color
green is somewhere in the middle of this spectrum. Since green is in the middle (photopic maximum), this is the reason why those older military night vision images were in green because at this color, the human brain can decipher contrast more so than any other color. Today, night vision technology combines both color and infra-red technology to provide the ultimate visible field for our fighting men and woman in the military. I call this stuff a I.B.U. (interesting, but unimportant)
So bottom line, white reflects ALL of the visible frequencies of color whereby black does not reflect any visible wavelengths. You need 3 things to have color: a light source, an object (coin) and a receiver/processor. Take one away, and you have NO color. The receiver/processor can be our eye/brain or the camera we use to receive and process the reflection of color from a light souce. It is this reason why coins that are photgraphed should be taken with a black background so that the immediate adjacent colors do not effect the coin's color wavelengths being reflected back into the camera lens. Also, consistent and color corrected lighting is vital too. The angle, the intensity of the light source and the distance should always be the same from object to object if you really want true color representation.
- Hal
Linear Mode
