Primary colors

Yes, size, 'surround' (ie, light or dark environment), even reflections, matter in this analysis, PE. Although contrast is usually deemed to be perceived as increasing when the print is 'surrounded' by environmental light (and decreasing when surrounded by darkness) this truism falls on its face with computer monitors because, there, the 'light surround' acts to lessen the increased contrast paradigm; that 'light surround' usually reflects on that monitor and, thereby, lowers that contrast. But, I am really lost here: when a 35mm slide is projected onto a screen, is not the contrast increased with a 'dark surround' and lessened within a lit room? I am missing something here.

Also, size seems to 'lighten' the print and this is known as the Bartleson Breneman effect. (This is why taking a small sample of a room color to a hardware store in order to get paint for patching up a room's walls can often prove to be disappointing.)

The Ancient Greeks built structures with modification of what objective pure logic would mandate: the Parthenon is not straight, it's 'stylobate' (the platform) curves slightly upward in the middle and its 'straight' Doric columns slant slightly inward. All this counters the pure logic of mathemantical rectitude but, wisely, rightly conforms, instead, to augment positive human perception. I do not think that it's achitects failed here.

So, yes, 'size does matter' (in this and other endeavors, PE). Also does the environment lighting (modified by potential reflectance on the image as with computer monitors). - David Lyga

I even once mixed slightly different variations of blue trim paint for different sides of the house, and what the color temperature of the angle of sun and nature of the atmosphere would most likely be a given time of day. In other words, if it wasn't a deliberate mis-match, and was all
the same correct color, the eye would think it was a mis-match! And when I could provide that same kind of service for architects, it paid well. Most of my business actually came from re-doing flubs from previous alleged color consultants who simply picked out chips from a chart in their office and charged for the service. Because I was also a photographer, I visited the actual site during different kinds of lighting, carried a color temp meter, studied the surrounding foliage and seasons, etc. But nowadays my wife picks the color, and I just say,Yes. It's a lot simpler that way.

DREW WILEY said:

I even once mixed slightly different variations of blue trim paint for different sides of the house, and what the color temperature of the angle of sun and nature of the atmosphere would most likely be a given time of day. In other words, if it wasn't a deliberate mis-match, and was all
the same correct color, the eye would think it was a mis-match! And when I could provide that same kind of service for architects, it paid well. Most of my business actually came from re-doing flubs from previous alleged color consultants who simply picked out chips from a chart in their office and charged for the service. Because I was also a photographer, I visited the actual site during different kinds of lighting, carried a color temp meter, studied the surrounding foliage and seasons, etc.

Click to expand...

This may be the single great post ever!

http://www.purveslab.net/seeforyourself/

see all Rubik cube topics and press play button for animation

If you want a point-blank tutorial on messing with the mind in terms of color physiology and psychology, look at some of Rothko's actual paintings.

DREW WILEY said:

If you want a point-blank tutorial on messing with the mind in terms of color physiology and psychology, look at some of Rothko's actual paintings.

Click to expand...

Ya, great stuff!

DREW WILEY said:

I even once mixed slightly different variations of blue trim paint for different sides of the house, and what the color temperature of the angle of sun and nature of the atmosphere would most likely be a given time of day.

Click to expand...

My work life has been all in photography, but I like to think I know something about color. Anyway, couple years ago I helped a friend pick colors for her house. It's in an historic district where visitors like to drive around and look at everything. I told her, I bet I can pick some paints for the front door that'll match during the day, but will shift slightly as the sun sets. The idea being that we could paint a pattern, that would only stand out shortly before the sun sets. She likes angels, so I said we could make the pale silhouette of an angel show up, and all the gawkers would think it's a miracle - an angel showing up just before nightfall to guard her house. We didn't follow through, for fear of religous zealots and the like, but I still bet it could be done.

There's a little more to the story, but first I have to deny being an artist or any artistic tendencies in my photography. My sister (who actually IS an artist, FWIW) noticed an article in the local entertainment newspaper. The "Paint Quality Institute" has this contest called the 12 "Prettiest Painted Places in America," and guess who's neighborhood was one of the winners. So my sister clipped the article and mailed to our mutual friend, who immediately called her. She said, "OMG, did you know that was my house in the photo? Your brother and [name of neighbor] painted it." So anyway, the only time I ever picked colors and painted a house (only the front gets painted, actually), it made it into the top of the "prestigous" contest.

http://www.dow.com/news/press-releases/article/?id=6043&from=redirect

In the architectural paint game, one obviously has to prioritize the time of day the given hue is most likely to be appreciated or unappreciated,
whether it's you when you arrive home from work at the end of the day, or some cranky neighbor across the street who stays at home. I've
done some strange things, including consults on rock star mansions where the color schemes got pretty weird. But around here we have a lot
of gorgeous Victorians and other expensive remodel project, some running in the millions. Routine paint jobs can literally run into six figure. One of the more memorable ones involved a gorgeous three story gingerbread Victorian beside a river north of here. The architect approached a well-known color consultant in the area, looked at a few photographs of the mansion itself, and fiddled around with some of his routine color chip schemes like might have been successfully used back in that area on things in postcard Steiner St Victorians in SF. So he came up with a bold interesting scheme with a dominant vibrant blue, which certainly looked pleasing in the office, and got duly paid. About
twenty grand of scaffolding and paint later, someone was starting to scratch their head. What the guy didn't both with is even asking what
the site looked like. What was paying for the entire remodel project was a rich alfalfa crop totally surrounding the building. In other words,
a world of electric green, providing an utter shocking clash to that intense blue paint scheme. So I get paid for both my own opinion and my
travel time, and when I get there I take my "before" shots of the whole scene, in 4x5 of course. A year later, I take the after shots, which
of course, the architect also handsomely pays me for, to showcase in his own portfolio for how the project came out. Nowadays I just don't
have the energy to run around and burn the candle at both ends like that, but it was nice income in its time.

At KRL we made an experiment in which a piece of paper appeared blank (white) under normal room lights but under UV was turned into a glowing full color image. The colors were radiant as they emitted visible light.

PE

David Lyga said:

For artists who mix paint, the primaries are RED, YELLOW, BLUE. In photography, the primaries are RED, GREEN, BLUE. Is there a simple explanation as to why there is a disparity? And, which set of three shows the most even and rational wave length separation?

I print color with plastic filters. To me, the 'red' seems less red and a bit orange. So, is 'red', RED?

This might be an interesting and informative discussion. - David Lyga

Click to expand...

The eye sees red, blue and green. The brain converts these three colors to yellow.

Rick A said:

David, the additive colors for printing are cyan, magenta, yellow (and black). These are also the filters I used to use for color separation work in a print shop whilst attending college. I have to add here, letter press printing (very little offset), I'm old.

Click to expand...

Rick A said:

David, the additive colors for printing are cyan, magenta, yellow (and black). These are also the filters I used to use for color separation work in a print shop whilst attending college. I have to add here, letter press printing (very little offset), I'm old.

Click to expand...

The long departed two letter troll insisted that magenta is not a color and that PE did not know one thing about film and processing.

Wonder what college that was? Not everything has the same kind of color vision. Here in the hills we have a "squirrel college" for rehabilitating
urban wildlife prior to sending it back into the wild. The print shop could hire squirrels.

Back to David's OP, namely "why the disparity". From what I understand...

It was originally believed (before the acceptance of science as the basis of knowledge) that red, blue and yellow pigments could be used to mix all colours that can be perceived by the human eye. This was in a time when white light was believed to give rise to colour through its interaction with "darkness".

Newton's investigations concerning the nature of light determined that white light was composed of a collection of different colours, together forming white. This white light, when shone through a prism, was diffracted and separated into the colour spectrum (that we are nowadays familiar with). When Newton used a second prism to further split the now-diffracted beam of white light, he found that there were three, empirical (primary) colours of light that could be used to create all others: red, green and blue.

At this point, humans now have an understanding of the (coloured) nature of light, but still no idea of additive and subtractive colour theory, let alone ideas of hue, saturation and tone.

The problem that artists have, is that if you take the primaries as red, green and blue (additive), you cannot get certain shades of yellow and brown that would be required in their palette, hence the continued use of the RYB model in art which does allow creation of these colours. You will note that modern artistic use of colour, e.g. the printing industry, has adopted a four colour system of CMY(k) (subtractive).

If you look at early colour theory literature, you will see that the "red" and "blue" of the RYB colour model are actually "almost magenta" and "almost cyan". I suspect it was then largely Chinese whispers, as "red" and "blue" are more likely to be understood than "magenta" and "cyan" when these new ideas were being disseminated to a relatively uneducated populace.

So, I guess the difference is a historical hangover of what would later emerge as additive (RGB) and subtractive (CMY) colour theories.

Or... having read most of the other posts in this thread, have I totally misinterpreted the question?

I have not read all of the posts in the thread, though I have read a fair number of them. What I write may overlap with what some others have written.

The notion of three primary colors is, at best, only an approximation explanation of color perception. The problem is that there is no combination of three primary colors that can be mixed so as to reproduce all of the colors that can be perceived by the normal human, regardless of whether one is working in an additive system or a subtractive system. There will always be some colors that cannot be accurately produced by mixing the mixing of three primary colors, regardless of which three colors one decides to pick as the "primary" colors.

As a simple example, suppose the additive primary colors were blue, green, and red. Aside from the problem of defining exactly what you mean when you say "blue" for example, a choice of blue, green, and red will make it (I believe) impossible to produce, for example, a true pure deep violet color. when I say "pure deep violet" I mean a single wavelength (perhaps 400nm) near the short wave length end of the visual range of humans.

One other point, related to the last. If you pick any three spectra to define the primary colors and try to use those three to match the color of a single wavelength of light you will find that, of all the single wavelengths that could exist (an infinite number) you will only be able to make a perfect match using mixed primary colors to, at most, three of the single wavelength colors. All other attempted matches will give an impure color match.

alanrockwood said:

The problem is that there is no combination of three primary colors that can be mixed so as to reproduce all of the colors that can be perceived by the normal human, regardless of whether one is working in an additive system or a subtractive system. There will always be some colors that cannot be accurately produced by mixing the mixing of three primary colors, regardless of which three colors one decides to pick as the "primary" colors.

Click to expand...

Alan, it would be better to qualify your statements a bit tighter by specifying "physically realizeable" for your primary colors.

The CIE system commonly uses a set of three primary colors which are not limited in the way you say. However, these primaries are "imaginary," and so the colors are matched mathematically. I try to always be careful with this, so make it a point to say physical colors, or something of that nature.

In my reference, post #34, your issue is that same that physicist Richard Feynman addressed in some depth in the ~1963 Feynman Lectures on Physics (part 35-3). http://feynmanlectures.caltech.edu/I_35.html

There is a beautiful blue dye used in cloth manufacture that, when photographed, turns out brown. This is due to the spectral curve of the dye and the sensitivity of the film and human eye to reproduce this color. I have worked with it several times and it is a real conundrum as to how to get it and the rest of the subject matter to photograph in a reasonable manner.

PE

Paint/Printing is a subtractive process, you start with a white paper backing and remove pieces of white. Light is an additive process, you start with black and add more and more. The two color sets are opposites of each other because they come at opposite ends of adding and subtracting.

To make a light mix more Red you simply add +Red. You're adding here because you start at black.

To make a print mix more Red you have to remove notRed (-Cyan and -Yellow) from the white you start with.

Note: IF your light mix is already as max brightness as it can go, then to make your light more Red now you have to... subtract -Cyan and -Yellow since you're now coming from the white paper backing end of this color thing. Same applies to printing, once you've removed all the notRed you now have to add more Red.

It's all relative to your base and the choice of RGB is based on how people see colors, which is why it's different.

Side story: I worked with a couple film engineers way back when. They delighted in going to company functions wearing classy, brown business suits which just happened to dive into UV and their event pictures always came out funny even though they looked very presentable in person