Colours? Light? Pigment?

[Soquili]

Trying to re-activate some old unused neurons http://www.talkgraphics.com/images/smilies/rolleyes.gif

Seeing the posts about CMYK and RGB, printers and Commercial Printers, monitors and calibration. I decided to try and recall all the things that teachers and professors have attempted to put into my head http://www.talkgraphics.com/images/smilies/eek.gif about colour.

Leaving all the Physics out of it. Frequencies and wavelengths require too much math. This left the fun classes, Art and Photography. Art dealt mostly with pigments; red, yellow, and blue. Photography dealt mostly with light; red, green, and blue. Mrs. Penkowsky would be proud, I think I got them right http://www.talkgraphics.com/images/smilies/biggrin.gif

I always got confused about the additive and subtractive more than which were the primaries for the two. I did remember that white is the presence of all colours and that black was the absence of all colours. I thought maybe if I can do something in XaraX, it would help me visualize which is which better.

So after a bit of playing around and some google searches to get some information (can't rely on the decreasing memory), I made the following image.

A poll some time back (can't remember when http://www.talkgraphics.com/images/smilies/frown.gif) showed that a lot of members are about my age, so I thought I would share http://www.talkgraphics.com/images/smilies/wink.gif

[Soquili]

Trying to re-activate some old unused neurons http://www.talkgraphics.com/images/smilies/rolleyes.gif

Seeing the posts about CMYK and RGB, printers and Commercial Printers, monitors and calibration. I decided to try and recall all the things that teachers and professors have attempted to put into my head http://www.talkgraphics.com/images/smilies/eek.gif about colour.

Leaving all the Physics out of it. Frequencies and wavelengths require too much math. This left the fun classes, Art and Photography. Art dealt mostly with pigments; red, yellow, and blue. Photography dealt mostly with light; red, green, and blue. Mrs. Penkowsky would be proud, I think I got them right http://www.talkgraphics.com/images/smilies/biggrin.gif

I always got confused about the additive and subtractive more than which were the primaries for the two. I did remember that white is the presence of all colours and that black was the absence of all colours. I thought maybe if I can do something in XaraX, it would help me visualize which is which better.

So after a bit of playing around and some google searches to get some information (can't rely on the decreasing memory), I made the following image.

A poll some time back (can't remember when http://www.talkgraphics.com/images/smilies/frown.gif) showed that a lot of members are about my age, so I thought I would share http://www.talkgraphics.com/images/smilies/wink.gif

[Soquili]

Oh, almost forgot. The CMYK thing was something I wanted to try and understand a little better. Gary mentioned something about using the new Show feature in X1 to see the Cyan, Magenta, and Yellow. So I play around with that also.

The composite overlays at the bottom seem to show that CMYK can't accurately reproduce the RGB colours from the fills at the top.

[raynerj]

Nice refresher Mr. Bill.

Thanks I needed that.

You know it, you see it, you use it. but half the time you forget it when you have a problem. http://www.talkgraphics.com/images/smilies/biggrin.gif

[jens g.r. benthien]

Soquili,

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Photography dealt mostly with light; red, green, and blue. <HR></BLOCKQUOTE>

Hm, no, I can't sign this. Take a white light beam and split it with a prism. You'll get the full range of colors, a continuous color space, not limited to 'steps' or a certain amount of colors - this 'limitation' is artificial for the computers... Depending on the film you will use, you can even capture infrared, ultraviolet and many colors invisible for the human eye.

But to keep things simple, yes, you are right.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> CMYK can't accurately reproduce the RGB colours from the fills at the top. <HR></BLOCKQUOTE>

The reason is not the CMYK colors, but the bare fact that the CMYK display is only a simulation of how a color print will look. There is one single big difference between art and traditional media like painting and electronic media like TV and computers:
TV and computers build the colors from RGB, and they are active, meaning the illuminate a screen coated with phosphor or tiny LEDs. The colors actually emitt the light, they 'glow'. Whereas in traditional media like painting, printing, photography the colors are reflective, meaning we can see or perceive them only because a relatively homogeneous white light (sun or artificial light) is directed to the carrier of the colors / pigments, which reflect the light and throw it back to our eyes, absorbing the rest of the spectrum (uh, tough one here for me, sorry if I can't explain in better in English).
Without an external light source the human eye wouldn't be able to see the colors at all.

But this simulation is a compromise. Depending on the carrier medium in print the colors appear bright or dull - the composition of the material and the coating result in a big difference of the final print.

It's kind of contradictory to show reflective colors on an active, light emitting medium. Would be the same as if you would try to simulate computer screen colors on printed paper ;-} - it wouldn't work in darkness.

A nice example: If you want a brilliant white paper surface, what would you do with the coating? Add more white? No, there is nothing 'whiter than white'. Instead you will add up to 3% soot (!). That means adding a matte black to white will end up with the ultimat white. That's one of the weird things in the paper production processes (I learned this while producing a 30 minute documentary film about a paper mill in Scandinavia).

In short words: if you enable the print preview mode, you will see the simulation of reflective colors on an active display, perceiving colors as they will appear on a carrier medium.

Are you confused now? Well, then I should start with the color perception of the human eye compared to the color perception of a parrot's eye, but this will be too long for a post in this forum ;-}.

Thumbs up, it's a colorful world - let's enjoy it!

[roman]

Jens when you don't fall to preaching-mode it's actually a very good reading http://www.talkgraphics.com/images/smilies/biggrin.gif Thanx!

[raynerj]

"compared to the color perception of a parrot's eye", Jens,

Hi Jens,

Would that be a Norwegian Blue? Is it the same if he is pining for the Forjds? http://www.talkgraphics.com/images/smilies/biggrin.gif http://www.talkgraphics.com/images/smilies/wink.gif

Or just when he is nailed to the perch? http://www.talkgraphics.com/images/smilies/cool.gif http://www.talkgraphics.com/images/smilies/biggrin.gif

Good info by the way. Thanks! Could not pass up the parrot joke.

[gwpriester]

Another factor is Gamut, which represents the number of colors possible in a given color space.

RGB has a far greater number of colors that can be displayed and viewed than does CMYK. I wrote about this many years ago, but sadly my brain does not retain the exact numbers.

Also, RGB color is essentially colored light, and which is much brighter than ink on paper. This explains why that brilliant sky blue you see on the screen prints much more muted in CMYK.

But if you really want to see incredible color, try to match the pale robin's egg blue of the sky, or the intense pale green of a spring leaf on the computer. What you have is very saturated colors with a very light values.

Gary

[jens g.r. benthien]

Gary,

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Another factor is Gamut, which represents the number of colors possible in a given color space. <HR></BLOCKQUOTE>

True, but that depends on the printing process. Offset printing is one track, digital printing another one. Digital printing allows more vivid colors, because the colors are not absorbed by the paper. With digital printing I don't mean the Heidelberger D1, but the laser like printing process. Best of all: this process doesn't require CMYK separations - a simple RGB TIFF will be all you need. But there are certain drawbacks: limited paper stock for the medium, limited variations for surfaces, and bleed requires a larger format which needs to be trimmed - which carries a high price tag compared to traditional offset printing.

John,

to be honest: I don't understand the joke. Maybe because I'm not from Norway? Anyway, my best friends are six African Grey Parrots and a Yellow Breast Macaw, and you better not nail them anywhere. I mean I wouldn't nail your kids to the barn door either.

But back to colors: did you know that Grey Parrots only appear to be grey for the human eye? They are very colorful - just use an ultraviolet lamp and you'll be amazed. You can find more details from Prof. Dr. Irene Pepperberg's researches & studies at her web site...

[Soquili]

Thanks everyone for your replies. Jens, a very informative response.

http://www.talkgraphics.com/images/smilies/redface.gif Perhaps I should explain that my posts above were more of an attempt to pass along some very basic info in a humorous way. I've been told that my sense of humor can be very bizarre at times.

I used to teach advanced colour techniques, which included how the human eye's rods and cones respond to light. I also won some Air Force photography awards in the creative catagory for my use of isophoto mapping. A technique used most often to apply colours to astronomical images.