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Subtractive color


fredreload

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There is no true black light. That's a phrase used for UV. If you filter out all the visible wavelengths, you have no visible light at all. You can buy filters to investigate this. (I have one of these)

 

Do you have a speculation to present here, or are you just asking a question?

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Looking for a pair of subtractive color glasses, what would the world looks like through it?

The link doesn't work.

 

 

P.S. The sky would look white I think, saves energy? Invisible ship?

Hard to say as the link doesnt work.

P.S. Black is a mixture of magenta, yellow, and cyan

Yes. But only in the CMYK color model (printing) And its not a "perfect" black too.

P.S. Magenta, yellow, and cyan makes black light?

No. CMY in maximum saturations make black (in printing for example) not black light. Black light is a popculture name for UV light btw.

What do you mean by "black light"

 

Black is lack of light, its not a color. Subtractive color model (CMYK) is used in printing where there is no source of light except the ambient light. If you were to use light emitting ink you could in theory print succesfuly in RGB. RGB color model (additive) is used in systems which use a source of light (tvs, laptops, projectors, etc) The two models are not compatible with each other.

 

Edited by koti
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Right I know, well alright, but what happens when you shine cyan, magenta, and yellow light together in this manner. The lights do not interfere and filter with each other right? What would the color be at the center?

 

 

P.S. They could be ambient lights, but what would be the result of these three ambient lights combined?

Edited by fredreload
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Right I know, well alright, but what happens when you shine cyan, magenta, and yellow light together in this manner. The lights do not interfere and filter with each other right? What would the color be at the center?

 

 

P.S. They could be ambient lights, but what would be the result of these three ambient lights combined?

 

Probably brownish color. But color perception is very subjective so hard to say.

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I'd like to know an actual result if someone decides to do an experiment on this

 

I've never done this but I presume that if you shine light from a source through a set of CMY filters (like the ones Swansont linked you) you will just result in a dimmer light. How much dimmer depends on the source and the filters.

PS. and no invisible ships nor camoulflage with this, sory.

Edited by koti
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I've never done this but I presume that if you shine light from a source through a set of CMY filters (like the ones Swansont linked you) you will just result in a dimmer light. How much dimmer depends on the source and the filters.

PS. and no invisible ships nor camoulflage with this, sory.

I was trying to reflect the three colors off the screen on a piece of paper lol, but most of them got black color at the center anyway.

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I was trying to reflect the three colors off the screen on a piece of paper lol, but most of them got black color at the center anyway.

Ask Swansont, maybe he will be kind enough to shine a flashlight through the CMY filters he's got and post a photo :) My bet is on dimm, brownish color.

Edited by koti
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So you don't expect too much of your experiment consider this;
The source (lets say a flashlight) is an RGB source of light. The Cyan filter will absorb the Red spectrum, the Magenta filter will absorb the Green and the Y filter will absorb the Blue. Guess what you will be left with.

Edited by koti
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Ask Swansont, maybe he will be kind enough to shine a flashlight through the CMY filters he's got and post a photo :) My bet is on dimm, brownish color.

 

 

I have to find them first. Not necessarily an easy task.

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Right I know, well alright, but what happens when you shine cyan, magenta, and yellow light together in this manner. The lights do not interfere and filter with each other right? What would the color be at the center?

 

I think it would be white again. In additive colour mixing (which is what this is) CMY are secondary colours, in other words, each of them is formed from a combination of two primary colours (RGB). So, indirectly, you would be mixing equal amounts of RGB.

 

Even if the CMY lights were (approximately) single frequencies, centred on those colours (and not a mixture of RG, GB, RB) I think it would fool the eye into seeing white.

 

It would be interesting to know what actually happens...

Ah, I see koti has confirmed my thinking with a much more logical argument. (Curse him! :))

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Ah, I see koti has confirmed my thinking with a much more logical argument. (Curse him! :))

 

I will save this comment of yours to comfort me when I'm in the relativity section of the forum ;)

fredreload, also consider that CMYK is a color model which was created and is used to present colors in systems without a source of light (printing, wall paint, car paint, etc) There is no such thing as a true CMYK light source from a physical point of view (and real life point of view as well) because visible light to us is essentially RGB. The RGB color model is what we observe in nature. If you send a beam of white light through a prism you will observe that it will diffract into the primary colors of red, green and blue. Or you can look at a rainbow too :) You mentioned that you tried to shine CMYK from your monitor onto a piece of paper...this doesn't make much sense in terms of experiencing CMYK colors on your sheet of paper. What you see on your monitor is always RGB - sRGB or Adobe RGB to be precise (these are standards put to cope with hardware differences) considering you are not using a monitor calibrated to some other specific color reference. In order to convert a certain color from RGB to CMYK we need some kind of color color management. If something is unclear I will be glad to answer.

Edited by koti
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I was trying to reflect the three colors off the screen on a piece of paper lol, but most of them got black color at the center anyway.

 

One interesting and important thing to come out of this thread.

 

I assume your paper was white?

 

This is the problem faced by projectionists since the beginning of time.

 

You cannot get true black on a white screen using light.

 

The black you see is an optical illusion that relies on both the ambient lighting conditions and the characteristics of the eye and brain.

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One interesting and important thing to come out of this thread.

 

I assume your paper was white?

 

This is the problem faced by projectionists since the beginning of time.

 

You cannot get true black on a white screen using light.

 

The black you see is an optical illusion that relies on both the ambient lighting conditions and the characteristics of the eye and brain.

The pursuit of a blacker black is on in other fields too. TV's (and screens in general), fine art printing, phtography, etc. The reason is the higher contrast you get with a blacker black. From my experience, the fine art printing market people are the biggest fans of blackest blacks possible.

Edited by koti
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Hmm, one thing remains in mind is, if you picture the world entirely with subtractive colors, what would the world looks like? This can probably be done with programming aspects, although I haven't seen such a function on OpenGL

You missed the point, read my posts again :) OpenGL as far as I know works with RGB and cannot know what CMYK is. You can only simulate CMYK on a device which uses a source of light (monitor)

Edited by koti
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Right, maybe with openCV. I mean the RGB color can be converted to its respective subtractive color through image conversion by changing the values right? After all it is just the absence of that color, but I was unable to find a simple subtractive color image of a room, or any other images on Google, which got me kind of curious. Do you happen to have a link of the subtractive image like that somewhere? And I don't mean just by a single color, all the respective color would be changed to its subtractive color like an unprocessed Kodak film

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Right, maybe with openCV. I mean the RGB color can be converted to its respective subtractive color through image conversion by changing the values right? After all it is just the absence of that color, but I was unable to find a simple subtractive color image of a room, or any other images on Google, which got me kind of curious. Do you happen to have a link of the subtractive image like that somewhere? And I don't mean just by a single color, all the respective color would be changed to its subtractive color like an unprocessed Kodak film

 

Do you understand that because there is no other black in the CMY palette, true black is added and represented by the letter K to distinguish it from blue?

Edited by studiot
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I was unable to find a simple subtractive color image of a room, or any other images on Google, which got me kind of curious. Do you happen to have a link of the subtractive image like that somewhere? And I don't mean just by a single color, all the respective color would be changed to its subtractive color like an unprocessed Kodak film

 

And you wont find it because id doesn't exist. You got it all wrong fredreload...if you choose not to read mine and Sudiot's previous posts, please start with reading the wiki on CMYK:

https://en.wikipedia.org/wiki/CMYK_color_model

 

Do you understand that because there is no other black in the CMY palette, true black is added and represented by the letter K to distinguish it from blue?

 

Exactly right. Also as a side note for fredreload, black is not a color. In real world black is lack of anything. In color management systems black is a channel. Also...CMYK is a model created only for printing. Black ink & toners were added because they give better results than composite black.

100% C + 100% M + 100% Y = black. But its not actualy black, its muddy, brownish crap. A dedicated black ink/toner gives deeper black.

As for why "K' is called "K" it's speculative...Some say it's "Key" some say it comes from black, some even say it somes from "Kelvin" as color temperature is measured in the Kelvin scale.

 

 

Edited by koti
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Right, maybe with openCV. I mean the RGB color can be converted to its respective subtractive color through image conversion by changing the values right? After all it is just the absence of that color, but I was unable to find a simple subtractive color image of a room, or any other images on Google, which got me kind of curious. Do you happen to have a link of the subtractive image like that somewhere? And I don't mean just by a single color, all the respective color would be changed to its subtractive color like an unprocessed Kodak film

 

Do you mean negatives?

 

https://en.wikipedia.org/wiki/Negative_(photography)

 

http://www.w3schools.com/tags/tryit.asp?filename=tryhtml5_canvas_getimagedata2

Edited by Endy0816
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Could be, I looked up on Kodachrome and it says it uses a Subtractive color method in storing the images that requires the use of glass plate negatives. I think Kodak films are stored with subtractive colors, but I could be wrong

 

 

P.S. So Koti, the subtractive color should exist, probably not with the CYMK method, thing is a Kodak film looks rather transparent. Kind of wondering what's with all the mysteries surrounding these things

Edited by fredreload
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