Paw Paw Bill Loc: d

Light is additive. Pigments are subtractive.

That said, the explanation is that adding blue light to red or green may change the color, but the light from the colors will be present. Pigments remove or subtract all colors but the one they reflect. Adding red, blue and green pigments means that substances will be present to absorb all primary colors and the result will be close to blace, depending on the ratios of pigments present. Adding red, blue and green light means all frequencies are present and will appear nearly white.

White light actually can be simulated with red, blue and green light. But true white will consist of more than just the three primaries. Our camera sensors stick to collecting only the three primary frequencies. The colors from our sensors will very closely approximate what we see, but can be measurably off because of this limitation.

White light is all colors added equally and black is absence of light. There is always some light reflected from black, but at low levels. True black is practically impossible to generate and would appear without dimension or variance on the surface of any item that could achieve true black. Texture visible on a white object also indicates variances in the color from true white.

Inks use Magenta, Cyan and Green because they are the opposite colors of the primary light colors. That is so that adding these subtractive pigments will add up to the positive color we wish to achieve.

qrpnut Loc: Brattleboro, Vt.

When I was a kid, we had our science classes at the local Fairbanks museum. In the basement they had a dozen or so scientific hands on experiments. One was a flat, round metal disc about a foot in diameter mounted on the shaft of an electric motor. This plate was painted all the colors of the rainbow plus black equally in pie slice shapes. When you turned the motor on and spun the disc, all you could see was white!

tinosa Loc: Grand Rapids Michigan

Hooray for you Qrpnut !
How can any one dispute that ?
Would love to find the video on Utube.


How interesting that they included a slice of black.

tinosa Loc: Grand Rapids Michigan

Thank you very much Bill for taking the time to add your detailed explanation, While I am still digesting it, the above paragraph was very enLIGHTening.

Thanks again. :thumbup: :thumbup:

tinosa Loc: Grand Rapids Michigan

Fantastic participation folks ! !
I am learning a lot.
Thank you.

wlgoode Loc: Globe, AZ

I sure wish they still educated our kids.

Don Butler Loc: NW Pennsylvania

Having had the experience of teaching in a tech school where students supposedly want to learn a trade, I can tell you this:
Teaching our kids doesn't start in the school.

Nuff sed!

db

wlgoode Loc: Globe, AZ

I've always held the point that parents are the primary teachers of children. If the school system is not doing it's job it is up to the parents to fill in the gaps. Parents must be lovingly vigilant.

JimH Loc: Western South Jersey, USA

Colors vary whether you're talking LIGHT or INK (Pigment)

Mix red, green and blue light - you get WHITE light.
Mix red, green and blue ink - you get BLACK ink.

Interesting, huh?

wlgoode Loc: Globe, AZ

Enough Already.

Dryart38 Loc: Carlsbad, NM

Aren't you folks forgetting yellow as a primary color? So far, all I've seen is red, blue, and green - green is a secondary color, not a primary. I'm not trying to be difficult, but I got lost when you started all the technical explanations - I photograph and I paint in oils, and I've always used red, blue, and yellow, and built up colors from there. In inks, magenta. cyan, and yellow were the starting point for colors. The rainbow explanation seems logical as far as what colors make white light - you don't fool with Nature!

ziggykor Loc: East Texas

Dryart, yes in the building of color using pigments yellow is a primary, but with light and photography it isn't. Just as our eyes diferentiate color through red, green and blue receptors, those same three colors in light when combined to various degrees render all the colors our camera's capture.

In the darkroom when working with color film we balanced color using what are called the subtractive colors of cyan, magenta and yellow. Theye are called subtractive simply because ruducing one color would increas another.

With positive film, slides, we used additive colors; red blue and green and increased a color to intensify a hue.

Now if you examine the tools in Photoshop you'll find that there are actually some that work with either process.

I hope my reply makes some sense, remember we're talking about the properties of light not making color using pigments.

Dryart38 Loc: Carlsbad, NM

ziggykor! Thanks for the enlightenment - physics was never my love - in high school, I dropped it because I was failing it miserabley! Thanks again!