Is it possible for a particular color to fall outside of the Portra 400 gamut?

Well, if you work for a print shop, or even any serious color photo lab, whoever signs your paycheck is infallible.
And you better be darn sure you understand what magenta means.

DREW WILEY said:

Well, if you work for a print shop, or even any serious color photo lab, whoever signs your paycheck is infallible.
And you better be darn sure you understand what magenta means.

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Jackpot! You broke the code!

DREW WILEY said:

Well, if you work for a print shop, or even any serious color photo lab, whoever signs your paycheck is infallible.
And you better be darn sure you understand what magenta means.

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Sirius Glass said:

Magenta is not a single wavelength, but it can be produced by numerous combinations of multiple wavelengths. So if one defines a color as a single wavelength, then magenta does not fit that definition, but any color can be made with combinations of multiple wavelength.

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Aye, Magenta in no primary colour or hue, those are red, yellow, blue, but a SECONDARY colour or hue.

It's bias can be red or blue, which combine to make the red and blue violets or a mid looking colour.

The addition of black makes a colour a "shade", white a "tone".

Kodak and every photographic manufacturer that ever made a gel, filter, colour index, etc that was named magenta have officially recognized the colour or hue as a photographic reality.

I've seen some beautiful photos from Portra 400 so technical ability plays some part, as in all colour films.

NAY - red, yellow, and blue are not primaries, even though we were taught that as children using finger paint, and sometimes eating it too. The Primaries are Red, GREEN, and blue. Yellow is a secondary, along with magenta and cyan.

But you probably just made a typo.

DREW WILEY said:

NAY - red, yellow, and blue are not primaries, even though we were taught that as children using finger paint, and sometimes eating it too. The Primaries are Red, GREEN, and blue. Yellow is a secondary, along with magenta and cyan.

But you probably just made a typo.

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Red, Green and Blue are used in our retinas and television screens but Red, Yellow and Blue are the primary colors.

Oh boy.

Red, Yellow and Blue are considered the primaries in general manner of speak, but ask a printer and they'll argue that cyan, magenta and yellow are the primaries (or, conversely, red, green and blue). So it depends on the context. Normally speaking, it's R/Y/B. If you go out and buy paints, you'll find that there's a lot more ways the term 'primary' is used; for instance, the Winsor & Newton have two sets of primaries (across two different brands, so 4 'primary' color sets in total). One of those sets is a three-color primary system using yellow, blue and red/magenta (the horror!), while their 6-color primary system consists of two shades of yellow (a greenish and an orangish one), two blue shades (again on both sides of the spectrum) and two reds. Note how they both boil down to a R/Y/B basis, but one of the systems having no less than six primary colors. What now?

Sirius Glass said:

Red, Green and Blue are used in our retinas and television screens

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Sort of. The peak sensitivities of our retinas are more like blue, green and yellow. The sensitivity of our M and L cones overlap mostly and are spaced only a small distance apart. We don't have any receptors for red, although our L-cones do have some tailing sensitivity in that area. The G and B in modern TV and computer monitors overlap fairly well with our S and M cones, but not with our L cones since the R in an LCD or OLED system will be >600nm.

It's all context-dependent as hinted at above and you could unfold it further if you want. When speaking of primary colors, it's sensible to just indicate which ones you mean with the level of exactness required by the application.

eli griggs said:

Kodak and every photographic manufacturer that ever made a gel, filter, colour index, etc that was named magenta have officially recognized the colour or hue as a photographic reality.

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Depends on how you define 'photographic reality'. A bit like if you consider zero a number. Magenta in photographic terms is 'not green'. Is that a reality? It's a construct that's graspable, and a reality that visually makes sense. For most, that's good enough. There's no wavelength of light that represents magenta, so for a physicist, magenta may not be a reality. Again - context-dependent. Not sensible to argue much about because it's never gonna get anyone anywhere.

Well, Winsor & Newton are in the business of paints - that would make them work in the additive subtractive domain. Yet, their primaries are red, yellow and blue, which is neither additive nor subtractive, but conforms to the traditional painters' primaries. Are they wrong? Is your graphic wrong? Are they both wrong? Or right?

Is this one of those things we're going to try and achieve 'consensus' on? I hope not...

The additive colours are referred to when talking about the transmission of light. For example colour photographic printing, television.

koraks said:

Oh boy.

Red, Yellow and Blue are considered the primaries in general manner of speak, but ask a printer and they'll argue that cyan, magenta and yellow are the primaries (or, conversely, red, green and blue). So it depends on the context. Normally speaking, it's R/Y/B. If you go out and buy paints, you'll find that there's a lot more ways the term 'primary' is used; for instance, the Winsor & Newton have two sets of primaries (across two different brands, so 4 'primary' color sets in total). One of those sets is a three-color primary system using yellow, blue and red/magenta (the horror!), while their 6-color primary system consists of two shades of yellow (a greenish and an orangish one), two blue shades (again on both sides of the spectrum) and two reds. Note how they both boil down to a R/Y/B basis, but one of the systems having no less than six primary colors. What now?



Sort of. The peak sensitivities of our retinas are more like blue, green and yellow. The sensitivity of our M and L cones overlap mostly and are spaced only a small distance apart. We don't have any receptors for red, although our L-cones do have some tailing sensitivity in that area. The G and B in modern TV and computer monitors overlap fairly well with our S and M cones, but not with our L cones since the R in an LCD or OLED system will be >600nm.

It's all context-dependent as hinted at above and you could unfold it further if you want. When speaking of primary colors, it's sensible to just indicate which ones you mean with the level of exactness required by the application.



Depends on how you define 'photographic reality'. A bit like if you consider zero a number. Magenta in photographic terms is 'not green'. Is that a reality? It's a construct that's graspable, and a reality that visually makes sense. For most, that's good enough. There's no wavelength of light that represents magenta, so for a physicist, magenta may not be a reality. Again - context-dependent. Not sensible to argue much about because it's never gonna get anyone anywhere.

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Primary colours are still the only set of "primary" hues , in red, yellow or blue, only.

For more accurate colour mixing, I and other artists will use a 12 colour wedge wheel, comprising of, in part, six primaries bluish red, orange red, orange yellow, green yellow, violet blue and red violet.

This gives rise to three sets of secondary hues and very many tertiary hues.

Process colours are a collection of both primary and secondary colours, but should no be called in the whole, "Primaries", even though they make up printer's 'primary' set of colours.

It is more appropriate and precise to say " this set of three or that set of four are the 'primary selection' of colours favored by printer processes.".

There are several ways to approach colour theory, but the basics are always based on the Colour Wheel, with reds, yellows and blues and the secondaries firmly settled in their places.

Cheers.

foc said:

The additive colours are referred to when talking about the transmission of light. For example colour photographic printing, television.

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Sorry, slip of the keyboard.

eli griggs said:

Process colours are a collection of both primary and secondary colours, but should no be called in the whole, "Primaries"

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You get to determine this?
So how do you argue that your set of six primaries when used in painting 'should' be called primaries?

To be clear, and not to be unkind, but I wasn't looking for a lesson in color theory - I was pointing out that the disagreement between two members above in this thread is kind of silly.

PS: this might be of interest to you https://www.handprint.com/HP/WCL/color14.html#splitprimary

Aren't most colors just a combination of various wavelengths? It's not that there is just one wave per color. Is there? So these combine in our brains and are interpretated by us as a particular hue. But it's not real; just a figment of our imagination, neural processing. They have no more color than gamma rays. Explain purple to a person who's been blind since birth.

Alan Edward Klein said:

It's not that there is just one wave per color. Is there?

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Many colors do. They can be construed in a number of ways that may look similar or identical to us, but that are different if your photospectrally map them. Those differences become relevant in e.g. color photography. See page 1 of this thread.

koraks said:

Many colors do. They can be construed in a number of ways that may look similar or identical to us, but that are different if your photospectrally map them. Those differences become relevant in e.g. color photography. See page 1 of this thread.

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Many? Of the billions of colors, aren't 99.9999% a combination of more than one primary?

You're not really going somewhere constructive with this.

koraks said:

You're not really going somewhere constructive with this.

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You didn't answer my question.

That is correct. The answer is irrelevant to the matter of this thread.

Oh, I wa going to try to help..: but maybe not now.

Feel free, just don't get your hopes up...

koraks said:

That is correct. The answer is irrelevant to the matter of this thread.

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The thread has long drifted into related territory. Feel free to let others respond.

foc said:

View attachment 345417

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What do you get if you reverse these: -add the subtractive primary inks or paints of green, red and blue and subtract the primary lights of magenta, yellow and cyan?

For those who are fans of the physicist Richard Feynman there is a "lecture" or two on human color vision in "The Feynman Lectures on Physics." (These were published early 1960s based on a series of lectures he gave to first and second year students.)


Figure 35-8 shows spectral sensitivities of human eye in agreement with what koraks had mentioned about two of our color-sensing functions having considerable overlap.

Feynman also points out, in section 35-3 "Now a question is, what are the correct primary colors to use? There is no such thing as “the” correct primary colors for the mixing of lights. There may be, for practical purposes, three paints that are more useful than others for getting a greater variety of mixed pigments, but we are not discussing that matter now."

As a side note when I was considerably younger (but still with a great deal of photo lab experience under my belt) I decided to dig deeper into the issues of "color" starting out with, what exactly are the wavelengths of, for example, red light? Because Kodak literature freely talked about such things as red, green and blue, along with cyan, magenta, and yellow (and actually manufactured such filters), I presumed there was some sort of hard definition somewhere. There is not. In the world of color photography (negatives printed to paper) there are certain spectral sensitivities of materials as well as certain dye/filter absorbances; these are made to work together in a complementary manner. So the "definition" of what is red and cyan, etc., is sorta established by the characteristic needed to be compatible.

Outside of color photography things get more vague. For example it is often said that the primaries (for light) are red, green, and blue. In the artist's world they are often said to be red, yellow and blue (subtractive primaries, fwiw). But with the vagueness of the definitions it's possible that the artist's "red" might be similar to the photographer's "magenta," and that the artist's "blue" might actually be similar to the photographer's "cyan." So in this interpretation one can see that the artist's red, yellow and blue might, in fact, be very similar to the the photographer's magenta, yellow and cyan, respectively. The vagueness of the color definitions makes this possible.

For anyone who wants to get their feet more wet in this sort of thing one of the best intros I know of was written by Fred Bunting to go along with an earlier handheld spectrophotometer (that company is now part of X-rite). The booklet is called The ColorShop Color Primer..., and can probably be found online.

Alan Edward Klein said:

Feel free to let others respond.

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Certainly so. That's the implied nature of a forum. Anyone can chime in.

And not excluding that possibility, I'll try to explain why I believe your question about 99.99% of the colors being mixes of primaries is not a promising avenue in the context of this thread.

Firstly, physics doesn't care about primaries. As @Mr Bill above explains (the Feynman lecture), there's no natural/biological given of a 'primary' color in human vision. It turns out there's no such thing in outside the biological realm, either. Any selection of colors that we call 'primaries' is a human construct, and nothing more.

This becomes especially apparent if you realize how colors are rendered in real life, especially in reflectance: they are are in virtually all cases broad reflectance spectra that reflect a mass of wavelengths at various efficiencies. Not only does that relate in no way to whatever primaries you could think of, it doesn't even involve any particular colors being reflected. The best characterization is 'a whole bunch of them'.

How large a bunch? Well, this leads me to the second reason why your question doesn't make sense to me. You asked if it's not true that colors are generally mixes of primaries instead of pure colors. Let's look at those pure colors for a minute, particularly on a spectrum. The rainbow is a good example. How many colors does it have? I'll save you the time of counting - it's infinite. It's a continuum, after all (there's some lumpiness due to emission spectra of the sun and blockage by the atmosphere, but it's still pretty continuous).

So there's an infinite number of colors that are constructed as a single wavelength. This means that the question "aren't there more colors that are mixed colors than distinct wavelengths" mathematically works out to "isn't there some number that's larger than infinity". If you want to work that one out, I can probably give you the number of a decent science faculty where you'll find many people better versed than me on this cross-section of science and philosophy. Don't count on any practically relevant conclusions.

There are some caveats; for instance, digital displays (and, coincidentally, pointillist paintings, or halftone screen printed media) do construct colors by combining a distinct set of primaries at various intensities or reflectance levels. However, this is of course just an optical illusion and the millions of colors constructed this way aren't real - they're the figment of our imagination that you alluded to earlier. But this is firmly limited to the domain of hues constructed by adjacent, distinct colors that blend into each other due to the limitations of human vision.

In conclusion, if you think your question through, you end up with the realization that (1) primary colors aren't very relevant in terms of understanding how color emerges, nor in how we perceive it and (2) that the story about reflectance spectra as ways in which color emerges is actually something I already mentioned (and illustrated) on page 1 of this thread. So one angle is a dead-end street that at best draws one into a swamp of semantics, and the other is a rehash of material that's already presented and there for the picking up.

Hope that helps.