Color Question

My recollection of mixing paints in art is that there are 3 primary colors: RED, YELLOW, BLUE.

If that is true, why to digital cameras have RED, GREEN, BLUE? Can't make a pixel to record pure yellow??

Larry

They are different color models. RGB are the common primary colors for additive color systems such as TV screens, projectors, etc. while RYB or CMYK are commonly used in subtractive systems such as printers, paints etc.

Guy

Thanks for the initial reply, Guy.

But......... you are way ahead of me. To me, RYB in painting is additive.

If you have the time........ Larry

There's a wealth of info on the web explaining this - just Google "color model."

Here's one simple illustration: Inside Graphics

Larry, I think the names are a bit confusing. It has to do with your starting point (i.e. starting from black or starting with materials that reflect light). I was able to find this on wikipedia. It seems to explain the concepts pretty well:

http://en.wikipedia.org/wiki/Subtractive_color

Ultimately the choice of actual colors is pretty arbitrary. It's just different standards that came about.

Guy

Larry, you sound like a great candidate for acquiring the book Professional Photoshop [5th Ed. or whatever he's up to] the Classic Guide to Color Correction by Dan Margulis. (or maybe you already have it.) I'm pretty sure he has a great expo. about this in there. Dan's books are fabulously detailed and he has a quirky & humorous way of taking highly technical info. about color but then personalizing or broadening it in some way that makes some the the info. stick with you... suddenly he'll be talking about Greek columns or something like that.... he's definitely your proverbial Renaissance man. Anyway, if I had more time here I'd go into this more, but here's a part to start you thinking-- a big part of this color theory has to do with light itself (in fact, that's the whole core of it). When using different media, our perception of color has to do with how light hits our eye. Evidently our eyes are only sensitive to red, green & blue. The presence of all these colors in the light that hits our eyes makes us perceive an absence of color-- i.e. whites, blacks & grays. [thank you to Dan for that]. So if you're looking at the light coming from your light bulb or a monitor, you'll perceive white or absence of color only when those 3 colors are all present. In contrast, when we paint, we can't get white when we mix RYB colors together equally. We can only get a brownish-blackish. Only the absence of those colors will leave us with the white of the paper, etc. I'm skipping a lot of important detail here, and I assure you Dan will straighten you out much better (!) But I remember an art teacher once reminding us that in light, white is the presence of all color, while on paper, white is the absence of all color. Unfortunately, I've gotta run & I still haven't really gotten to your question of why no "Y" except within the green? Hopefully someone else can pick up from here. Great question, btw!

oops, thanks, Guy-- looks like we were busy answering at the same time. I'll check that out later.

Wow, thanks.
Possibly more than I bargained for, eh?
Will pursue Wikipedia and I'm eventually going to obtain PS so perhaps Margulis's book soon would give me a head start.
Thanks to everyone for their incisive replies.
Larry

OK, I think I've digested the additive and subtractive color.
So........ I presume all the calibration of printers is based on switiching from the digital additive concept to the printing subractive idea.
Is there a way in which to make the digital image print with additive methods thereby eliminating "calibration" problems? Probably not or it would have been done--unless an example of not thinking outside the box.

Larry - Additive color requires something to generate light. Doing it for printing would require some sort of light emitting paper, which I'm not sure is a good idea. Things like E-paper might be a way to go, but they're still usually using reflected light, which necessitates a subtractive model.

David, thanks for your last reply. The e-paper is something, and I wonder if we were the observer's of the Wright brothers what might be available in printing 10, 15, 50 years from now. And by the way, your portfolio I like. Many people seem to magnify color to an unreal status. That may be OK ocassionally but I think it is overused. Yours appear to minimally boosted. I like your colors. Larry

Thanks Larry! I really need to update it though....I started to and fizzled out a few months ago...