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

DREW WILEY

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Wrong, Koraks - the printing industry, just like tricolor photography, relies upon RGB primaries to generate its separations (and sometimes a K separation too for black per se), and these in turn determine the frequency of CMY ink or dye secondaries. CMY are never primaries, and certainly not in an standardized color theory text or vocabulary. Human vision also works on RGB initial physiological response. But successive contrast responds in a manner directly across the color wheel, in order to rest or reset the cones. Stare at a bright green object, and then close your eyes - you'll see magenta.

No serious art color theory book speaks of yellow as a primary. Only kindergartens do. Get ahold of any basic textbook on Color. We're talking about STANDARDIZED NOMENCLATURE.

Like I implied earlier - all of this can get twisted and convoluted in any manner typical web nonsense wishes; but if your supervisor in a print shop asks for a set of Red, Blue, and Green separations, he doesn't mean substituting Yellow for Green! - it won't work! And that's not just semantics. It's baked in.

Nor does any Kodak or Fuji color film technical sheet show sensitivity graphs in relation to RYB spectral peaks, but only RGB. They might get annoyed too if some employee didn't fully understand the distinction.
 
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koraks

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DREW WILEY said:
We're talking about STANDARDIZED NOMENCLATURE.
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It's not standardized across all domains. That's my point. It's standardized in different ways in different domains. That's why you got into a disagreement on it with Sirius. I'm not looking to perpetuate it. If you want to disregard or ignore where the disagreement came from, that's up to you. I see not merit in it.
 

BrianShaw

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Standardized how - de Jure or de facto? Any time I ever needed precise specifications of color we used Pantone specifications. Are there other standards? Names of colors, alone, are just names.
 

Sirius Glass

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Any three colors can be used to obtain any color. Red Yellow Blue are called the Primary Colors. In graphic arts, projection, computer science and the printing industry Red Green Blue are used for technical and practical reasons. No right or wrong, just conventions.
 

BrianShaw

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Then what is CMYK?
 

faberryman

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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.
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I have no idea what you were taught in kindergarten about finger paints or why, but if you were taught that red, yellow, and blue were the primary colors, it is quite possible that your kindergarten teacher went rogue.
 
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BrianShaw

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faberryman said:
I have no idea what you were taught in kindergarten about finger paints or why.
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Did anyone else eat the paste in kinder? That was almost as good as sniffing mimeograph solvents. We didn’t know the word “huffing” back then.
 

DREW WILEY

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Yes, different domains like Kindergarten finger painting versus actual adult color pros. There's nothing relative about it. Take that physicist you cited. If he was somehow selected to participate in a flight to adjust the Hubbell Space Telescope, and had to work with a particular control panel in the process, he'd sure need to be able to distinguish a green button from a yellow one, and not be all tangled up in thoughts about what all the complexities color vision really consists of. All that might be highly interesting in its own right. But here we're into common sense photographic topics, not neuroscience. And normal human color vision is implied.

It can sure all be fun, however. I myself often drift off topic due to some debate of another. So I don't mean to criticize your referral to certain interesting physics lectures in their own right.

The reason that computerized industrial applications like inkjet printing and computerized architectural paint coloration gets so complicated is that there are simply no suitable CMY process color sets for that. If there were, they'd need only three colorant nozzles, and not 11 or 13 of them, or whatever. Even CMY dye transfer printing often requires alternate or supplementary dyes to represent certain hues. Technicolor would tailor the dyes to match the movie sets and costumes. Most ordinary offset printing isn't that finicky, but still has a selection of CMY inks to choose from, plus K black, and sometimes adds other correction tweaks of some supplementary color if a high end level of repro is demanded.

That has nothing to do with the theory of color itself - just the limitations of the commercial dyes and pigments which are realistically available in terms of cost, dispersion qualities, lack of toxicity, and in the case of inkjet, mandatory tiny particle size. Nor are the dyes in color film ideal either, as well all know. Some films respond to certain colors better than others.
 

eli griggs

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For any wanting to know more about colour wheels, theory, start with Ittan's "The Elements of color", link below.

For more on the twelve step colour wheel, read and enjoy, James Clerk Maxwell's books and colour wheel templates.

When I post here, I generally write for the group, no individuals, in most cases, hopefully sparking interest in others, and the post writer whom I am responding to.

And, no, I am no prompting a casual overview of colour theory but rather, the well acknowledged basics of colour, itself.

The writers I refer to below are well grounded in their writings and accepted by millions of artists Worldwide, for Itten in particular, for many, many years.

It's up to readers here to explore what either man is speaking to, in depth, for themselves.











https://www.ebay.com/itm/394731356050?hash=item5be7d27f92:g:AvQAAOSwwvFkqH7M&amdata=enc:AQAIAAAA4CPGWEz95YtmYunbJhEbp4zme5F4fnOVexKNqTVK6OJop3NlxbgYPr7niSMnE6ZjBzOV8oODuEWBl0j/K7XEmhoYppetts+KKA2FnkxmhjDLX0CRsLWfepLs+ZQ3fR9xlRmczN1mwnaM9uSXD0IStKSm1L/uCSqDhL+HjqIyiHutTOSZ8+TGG5OLql4E71AhFqtYdnb092FXTB4DsDFj9dBBHBkAF1OyVWKWO2aipOVKiRQ++J5LJnFcyJ4IJCXjR7vpuqMZ+BfRdGH9RCs+ZSRT8xhoDBoX4X2aPmDJ5Gv2|tkp:BFBM2KGvqLZi
 

Rolleiflexible

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koraks said:
Now, we've arrived at the really tricky bit, and frankly, I don't know nearly enough of this to say much about it - but it's us, and our own, human eyes.
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To me, this is by far the most interesting part of this discussion. I am partly colorblind. I almost never shoot in color because I have no confidence that my idiosyncratic experience of color works for other viewers.

There was a fascinating Radiolab podcast on this subject ages ago. One takeaway is that perceptions of color are driven as much by culture as by biology. Western civilization was late to the concept of “blue.” If you read Homer, he has no references to blue. He describes the Mediterranean, that big blue bathtub, as “the wine-dark sea.” Now we see blue everywhere. What did Achilles and Agamemnon see?

 

koraks

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@eli griggs thanks for the references; much appreciated!

And @Rolleiflexible that's a funny thing about the blue/green thing, isn't it? Linguistics play a role, although I'm very hesitant to believe that as long as people don't have the language to differentiate between hues, this also necessarily affects their ability to discern them. How it relates to experiencing them is yet another issue.
 

Rolleiflexible

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I know this discussion has been long on physics but psychology, physiology, and linguistics all play far deeper roles in any real understanding of “color.” At least they seem more central to me.
 

faberryman

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I was trying to remember why we were having this discussion, so I read the OP, and it turns out that Portra 400 may have some inability to correctly capture the color colloquially known as purple. Have we determined that this is a shortcoming of the film or is it a linguistics problem?
 

reddesert

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Color theory and perception is a complex subject. It has aspects of both physics and physiology. The diagram posted by foc about additive and subtractive color mixing, and other resources on color theory posted in this thread, have a lot of information if one is willing to study them for a while, beyond posting snap responses about whether or not it supports a particular internet argument.

I think an interesting thing about Steven's example of a purple color that did not render correctly on Portra is that the film is clearly detecting at least some of the light reflected from this color. You can tell this because it didn't turn out dark. However, the way the film layers and dyes combine to render the color in the output does not match the way our eyes and visual system perceive the color. (There's also the scanning process, etc, but I think it's at least partly established that this is a property of the film and not a particular scan.)
 

DREW WILEY

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When I was doing color seminars, that classic little Itten book was standard reading. I was training people who were basically apprenticing in color matching positions. It could sure get funny sometimes, however. One of the matchers did his job and left the formula for someone else to simply replicate in 5-gal batches. That second individual mistook red oxide for red toner - same pigment, but 8 times stronger. Then one of my office mates who is color blind and sees only blue was asking around if there was any leftover off-white paint. His wife, who was away for the weekend, wanted him to repaint the inside of the house. So someone handed him a 5 gal bucket of the screw-up batch. He applied it all through the house; and it looked fine to him. But when his wife came home and saw brick red instead of off-white, all hell broke loose.

But to infer how color theory works depends on one's culture is utter nonsense. Specific names for certain hues obviously vary by civilization and dialect, depending on their sources of dyes and pigments, and traditions. But additive color always involves what is officially termed red, blue, and green, and subtractive, always yellow, magenta, and cyan. These are defined by specific wavelengths along the visible spectrum, no matter what culture you are from.

It is indeed a much more complex topic once you factor in psychological variables. That doesn't change the colors themselves, with respect to normal human vision, but brings in a lot of secondary factors. In fact, just learning to perceive hue distinctions accurately takes a lot of training and experience - just knowing what to look for, and how to look at it in any particular setting. An architect once paid me a fair amount of money to drive out of town and figure out why a very expensive Victorian paint job a different color consultant had specified looked so strange. Well, the other guy never visited the site, and only looked at pictures of the building itself. So he specified a strong blue with burgundy trim. Problem was, the structure sat right in the middle of a bright green alfalfa field, and color "clash" would be an understatement, plus all the green reflections onto that building. It had to be totally redone. The alfalfa fields paid for everything; so those weren't going away.
 
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Alan Edward Klein

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My mother was color blind which usually means you can see color, just not all of them. When she played Mahjong, she couldn't tell the difference between the blue and green money chips. When I joined the USAF and was guaranteed electronics training and assignment, they first gave me a color test to assure I wasn't color blind. No electronics if you are. For example, resistors have color coded stripes on them the gives you their value. Assembly wiring is color coded.
 

Alan Edward Klein

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Here's a test for colorblindness. Some of you might be surprised when you take it.

EnChroma® Free Color Blind Test | Test Your Color Vision

Take the free Enchroma color blind test to accurately assess your color perception. The results provide a recommendation for EnChroma color blind glasses.
enchroma.com
 

foc

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reddesert

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A color vision perception test that is more delicate than color-blindness, is the Farnsworth-Munsell test that asks you to sort sets of subtly different hues in order. X-Rite has an abbreviated version of this test on their website that you can do in a few minutes on a computer. Try it here: https://www.xrite.com/hue-test
The point of doing this is not that scoring lower makes one more accomplished, of course, but that it may reveal subtle differences in people's color perception.
 

BrianShaw

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I would have thought that a Portra colorblindness would be well known, if not well understood, by now. Portra’s not exactly a new film; it’s a rather well known standard. Lots of Portra has been exposed and seldom are there complaints except when someone doesn’t understand the film’s inherent characteristics. I’m not convinced the original issue is a film problem, per se.

At the risk of extending the side discussion, may I throw on the table another variable not yet discussed… the well-known problem with photography and satin fabrics. Here is one of many discussions (somewhat randomly picked but seems to be comprehensive per my faltering memory):

Do Satin Dresses Photograph Well? What to Know

Wondering if satin wedding dresses photograph well? Discover expert insights and tips for capturing stunning satin gown photos.
julianribinikweddings.com
 

foc

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Do Satin Dresses Photograph Well?

Thank you for posting this.

It brought back memories of trying to photograph Bridesmaids dressed back in the 1990s. At the time there was a fashion to have emerald green or series pink satin dresses.

Photographing the dresses outdoors in daylight, with Fuji Reala, was not a problem. But once flash was used, the problems emerged. Didn't matter if it was direct flash, fill-in flash or bounce flash, there was always a problem (in the bride's eye) with the colour of the dresses in the photos.
 

DREW WILEY

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Satins and velvets could even drive spectrophotometers crazy. And now you've got a special satin surface RA4 color paper from Fuji specifically designed to frustrate copying or plagiarizing the image.
 
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