We been lied to about color!

[patrickg]

Howdy folks, Thought I'd stir up some hate and discontent on my own instead of having to jump into a fray in progress (catepillar tracks for a tractor thread)

We have been lied to throughout our school days and beyond regarding color.

We are all pretty much taught the additive and subtractive theories of color as we grow up and go to school. You know, blue and yellow make green. Red, blue and green like in a RGB color monitor reproduce the full rainbow of colors visible to the human receptors. Or you can go the Cyan Magenta blah blah blah route.

OK, a thought experiment. If a picture of a color scene of a nice blue tractor (I'm a Kubota owner, the blue has a material bearing on the following discussion) is taken using black and white transparency film (positive film rather than negative, likek a slide but in B&W) exposed through a green filter and the exact same scene is photographed also with B&W transparency film through a red filter. The frames are developed and the resulting transparencies are projected onto a screen one at a time. First lets project the red image through the original red filter.

What do we see? A picture with contrast and rendition based on the amount of red in various objects. The picture could be said to be black and red rather than black and white when viewed on the screen. Now project the picture originally taken through the green filter on the screen but don't use a filter.

What do we see? A black and white image with contrast dependent on the green content of the original scene.

Project the two versions of the scene superimposed on the screen. What do we see?

What indeed. Maybe a pink and black picture. We have red light painting a picture on the screen through a positive transparency and white light painting the same scene through a different transparency. Shouldn't what we see on the screen at any given "POINT" be composed of from 0-100% red mixed with 0-100 white. Shouldn't that be a pink and white picture? Do we see any blue on the blue tractor and if we do where did it come from given we had white light and red light to mix together in shades of pink, how could we get blue?

Right after a few folks volunteer to give a reading on their understanding of what you will see on the screen, I'll amaze you with THE TRUTH and a ref to where to find out more and stuff like that.

Patrick ( Reminded of the way to keep tractor folk in suspense for 24 hrs, , I'll tell y'all tomorow)

 

[jinman]

Uhhh...all I shee ish pink elephants. Do you shee 'em too, Pahhhtrick? burp!...Jush wonderin'.../w3tcompact/icons/wink.gif

JimI

 

[DaveNH]

And a big white rabbit! /w3tcompact/icons/smile.gif

We're all in this together! (3)
Retired Yuppie Tractor Owner

 

[RSeymour]

Patrick, you have way to much time on your hands. You need to spend more time on your tractor.

 

[JonE]

Speakin' of colors, Dave, you've been watchin' the Red-Green show, haven't ya?

 

[toddler]

Red shouldn't expose the black and white film. Thus the red light in B&W dark rooms. So the negative should be black, right? Projecting through a red filter won't make a difference there. That leave the green filter shot, which would just look like a super high contrast shot. No?

oops, you said positive film, don't know, would that work in reverse, no picture on the green shot, then the red shot would give you a similar result. Hmm, gonna have to look up what wavelengths expose B&W slide film.
Todd
<P ID="edit"><FONT SIZE=-1>Edited by toddler on 07/20/01 02:59 PM (server time).</FONT></P>

 

[patrickg]

Too much time on my hands, indeed! (Non segitur as my watch doesn't have hands) I spend a lot of quality time with my Kubby but do like to have things to think about while spending so much tractor time.

Patrick

 

[patrickg]

I'll save you the trouble. The film is panchromatic, and red lights are NOT safe with it. Any film that can take a picture of a red thingy is not safe with a red light.

THE ANSWER (and I don't mean 42)

You get a full color picture on the screen just as if it were taken with Ectachrome. You could have projected the green image through the original green filter (along with the red) and gotten a full color picture as well but it isn't required.

So boys and girls, how does it work? How can a varying amount of red and green light make a full color picture? Where does the blue and yellows come from, etc etc???

This has been done and the famous Dr. Land of Polaroid Land camera fame did it. It can be reproduced by a school child. I did it when I was in school after reading about it in "Scientific American".

Some engineers made a two phosphor (red and green) TV but it was not compatible with regular broadcast TV.

The important part is that what we were tought in school about color is wrong. The color wheel and additive color and subtractive color parts of accepted color theory are explanitory but not neccessarily predictive. Explanatory theories explain things but might not predict an actual result therby showing that although they seem are plausible they are not correct. To be correct, a color theory it would have to explain Dr. Land's results.

Long accepted practice and deep held beliefs of whatever ilk might ought to be reexamined periodically or at random but frequent intervals.

Patrick

Patrick

 

[frank_f15]

patrick: i only understood about every tenth word u said(i am into photgraphy) but my ANS. WOULD BE ORANGE/w3tcompact/icons/smile.gif if its orange it can't be bad. just funning with u./w3tcompact/icons/wink.gif

 

[patrickg]

The answer is full color. Seems wrong, flies in the face of all the color stuff you have been taught additive or subtractive but it is true. Seems color reproduction, not just our perception of color just doesn't work thte way it has traditionally been taught. Photos were taken of bottles of chemicals of various colors by the method I described. They reproduced correctly. Since an observer wouldn't know what color something was supposed to be there would be no psychological mish mash involved. Spectroscopic examination would reveal the correct colors. It isn't a trick of perception or otherwise it is just way different from what we were taught.

The world continues to revolve on its axis and follow its orbit around the sun and we continue to use the plausible but totally incorrect stuff we were taught. Dr. Land published the article I am referencing in the early 1960's. As you can see,basically few people know or care. We just plod on secure in the knowledge that we are taught the truth. The scary part is, how much more of this is there and how important is any of it. If you don't know the truth it is hard to progress the state of the art. Sure, babies are found in a cabbage patch or brought by a stork. That is likely to stimulate correct scientific enquiry.

That creaking sound? The soap box can only suppport my weight so long, gota get down.

Patrick