# What is going on in certain marine life photos in terms of color mapping or saturation? **URL:** \ **Category:** Factual Questions\ **Created:** [November 12, 2019, 1:35am UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308 "2019-11-12T01:35:59Z")\ **Posts on this page:** 17\ **Page:** 2
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [November 13, 2019, 9:43pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/21 "2019-11-13T21:43:40Z")
> [@Pleonast](#): > > Once you change the color balance (whether by illumination or filter or computation), it’s not true color. I understood you the fist time. I’m pointing out that your your statement implies that “true color” is not an intrinsic property of an object, but dependent on the environment. Problem is, the human eye, as well as every digital camera (and prints made from film), compensates for color balance of the lighting. If no compensation is done, everything will look bluish in daylight, and very red under indoor home lighting. So what’s the true color? ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 13, 2019, 9:50pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/22 "2019-11-13T21:50:29Z")
> [@Pleonast](#): > > Once you change the color balance (whether by illumination or filter or computation), it’s not true color. By your definition, then, there is no such thing as “true color.” Or if you define “true color” to be that color balance, as perceived by the human visual system, produced by the illumination of full sunlight, at a certain latitude, at a certain time of day, with a particular clarity of atmosphere, you are almost never going to be able to see “true color.” ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [November 13, 2019, 10:08pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/23 "2019-11-13T22:08:04Z")
True color is the actual color of something when seen by an unaided human eye in the local environment. It’s not a characteristic of an object; it’s a characteristic of an image. A quick [Wikipedia](https://en.wikipedia.org/wiki/False_color#True_color) search says this: “An image is called a true-color image when it offers a natural color rendition, or when it comes close to it. This means that the colors of an object in an image appear to a human observer the same way as if this observer were to directly view the object” Maybe “true color” is used differently in your fields, but my usage is standard in mine. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [November 13, 2019, 10:17pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/24 "2019-11-13T22:17:55Z")
What field is that? ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 13, 2019, 10:29pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/25 "2019-11-13T22:29:27Z")
> [@Pleonast](#): > > True color is the actual color of something when seen by an unaided human eye in the local environment. It’s not a characteristic of an object; it’s a characteristic of an image. > > A quick [Wikipedia](https://en.wikipedia.org/wiki/False_color#True_color) search says this: “An image is called a true-color image when it offers a natural color rendition, or when it comes close to it. This means that the colors of an object in an image appear to a human observer the same way as if this observer were to directly view the object” That’s far from precise. In particular, what does “directly view an object” mean? The “true color” is going to vary with characteristics of illumination. Unless you define what that standard illumination is, then you can’t say what “true color” is. If you define standard illumination as full sunlight in air, then the color of a marine organism under artificial light of equivalent intensity to sunlight could well be closer to “true color” than the animal as seen in deep water. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [November 13, 2019, 11:07pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/26 "2019-11-13T23:07:26Z")
> [@Pleonast](#): > > A quick [Wikipedia](https://en.wikipedia.org/wiki/False_color#True_color) search says this: “An image is called a true-color image when it offers a natural color rendition, or when it comes close to it. This means that the colors of an object in an image appear to a human observer the same way as if this observer were to directly view the object” That is in context of true color vs. false color, where “false color” means the color in an image represents some quantity other than red/green/blue in visible light. That’s not what we’re talking about in this thread. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [November 13, 2019, 11:10pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/27 "2019-11-13T23:10:17Z")
> [@Colibri](#): > > That’s far from precise. In particular, what does “directly view an object” mean? The “true color” is going to vary with characteristics of illumination. Unless you define what that standard illumination is, then you can’t say what “true color” is. If you define standard illumination as full sunlight in air, then the color of a marine organism under artificial light of equivalent intensity to sunlight could well be closer to “true color” than the animal as seen in deep water. Directly view means looking at it with your eyes, without anything adjusting your vision, like a filter, polarizer, etc. Standard illumination is the natural in-situ illumination at the time the photograph is taken. You’re still thinking of true color as a property of the object and not a property of the image. True color photographs of a single object are going to look different depending on time of day, cloud cover, street lights, and so on because a human observer’s perceptions would change. I’m sorry I can’t go into specific details. I don’t do calibrations myself. The sensitivities of the human eye is fairly well characterized. The sensitivities of various sensors are known as well. It’s a matter of computation to convert from one to the other. The effects of lighting and filters can be included as well. The OP asked about color in underwater photos, and I wanted to comment on adding extra red light. It’s not going to produce an image representative of what a person swimming in the water will see–that is, it won’t be a true color image. “True color” using my definition. Maybe you can explain your definition to help me understand your questions better. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [November 14, 2019, 12:27am UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/28 "2019-11-14T00:27:09Z")
> [@Pleonast](#): > > You’re still thinking of true color as a property of the object and not a property of the image. It can be either, depending on context. If someone asked you what color a beluga whale is, would you say they are [white](https://en.wikipedia.org/wiki/Beluga_whale#/media/File:Delphinapterus_leucas_2.jpg)? Or would you say they are “usually [blue](https://www.internationaltraveller.com/snorkelling-beluga-whales/)”? ---
**Author:** ![RioRico](https://avatars.discourse-cdn.com/v4/letter/r/f04885/32.png) [@RioRico](https://boards.straightdope.com/u/RioRico)\ **Post date:** [November 14, 2019, 7:00pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/29 "2019-11-14T19:00:19Z")
‘True’ color is like an idealized ‘straight’ line - a theoretical construct only. What any human sees is a function of light source temperature, intensity, and direction; environmental conditions; personal physiology; and more. Motorbikes approached our car last evening with bright running lights. I saw them as amber; my wife saw green. Which is true? ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 14, 2019, 7:18pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/30 "2019-11-14T19:18:39Z")
> [@Pleonast](#): > > The OP asked about color in underwater photos, and I wanted to comment on adding extra red light. It’s not going to produce an image representative of what a person swimming in the water will see–that is, it won’t be a true color image. “True color” using my definition. Maybe you can explain your definition to help me understand your questions better. I think the average person would think of “true color” to be the color as seen in full sunlight, without filtering out of any wavelengths. It’s a property of the object, not the image. I believe that **Iggy** was most likely using the term in this sense. Most people wouldn’t regard the “true color” of an object in the dark to be black. To the extent that a flash or artificial light will produce a illumination similar to that of sunlight, compensating for the red wavelengths filtered out by the water, then an image will be closer to that seen in full sunlight. The OP was asking if the colors of the photos were the result of filtering, tweaking, or mapping. Even if they were produced using artificial light, and aren’t the same as might be seen underwater, in general they aren’t the result of manipulation. ---
**Author:** ![ArslanWilson](https://avatars.discourse-cdn.com/v4/letter/a/6de8d8/32.png) [@ArslanWilson](https://boards.straightdope.com/u/ArslanWilson)\ **Post date:** [November 15, 2019, 4:52am UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/31 "2019-11-15T04:52:45Z")
> [@MrDibble](#): > > That too. But some of those photos are just obviously shot without flash. Indeed. Flash actually has relatively limited applications. While it helps to even out light in marginal situations, going without actually leaves a lot more options open WRT color and shade manipulations. Especially if you can control ISO, Exposure time, etc. . . > [@Kimstu](#): > > In other education news, TIL that the plural “nudibranchs” is spelled that way because the singular is pronounced “nudie BRANK”, not “nudie BRANCH”. I had been saying the word “nudibranches” in my head and wondering why the hell nobody could spell it correctly. Ignorance fought. FWIW, I was _19_ when I figured out that the end of the world was not actually pronounced “R-Maga-Don”. This is why I don’t get to make fun of the way other people pronounce things. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [November 16, 2019, 2:04pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/32 "2019-11-16T14:04:47Z")
I pronounced the sea creature’s name “sea anna-moan” until I was 10 or so. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [November 16, 2019, 2:14pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/33 "2019-11-16T14:14:48Z")
> [@ArslanWilson](#): > > Indeed. Flash actually has relatively limited applications. While it helps to even out light in marginal situations, going without actually leaves a lot more options open WRT color and shade manipulations. Especially if you can control ISO, Exposure time, etc. . . This is a very odd thing to say. With flash, you have all the non-flash options available, plus the ability to add and sculpt light as needed to create the mood of a scene. Flash and other artificial lighting sources are quite important tools in a photographer’s toolbox. Sure, you have some people who do “natural light photography” and some photographers who are pretty much studio-only in controlled flash situations, but most of us combine the two. I often get a bit lazy and don’t bother to pull out the lights if I don’t need to, but holy crap can they make a boring, flatly lit picture interesting when used well. Anyway, I thought of this thread yesterday. Petapixel [linked to an article](https://petapixel.com/2019/11/13/this-algorithm-can-remove-the-water-from-underwater-photos-and-the-results-are-incredible/) about an algorithm that is being developed that eliminates the blue cast and backscatter from underwater photographs to make it look more like what they would under daylight conditions on land. > [@](#): > > An engineer has developed a computer program that can, in her words, “remove the water” from an underwater photograph. The result is a “physically accurate” image with all of the vibrance, saturation and color of a regular landscape photo. While I see that “true color” may be a term of art in some professions, to me, when I think “true color,” I think of that type of lighting situation. ---
**Author:** ![brossa](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/brossa/32/3040_2.png) [@brossa](https://boards.straightdope.com/u/brossa)\ **Post date:** [November 17, 2019, 5:17am UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/34 "2019-11-17T05:17:33Z")
> [@MrDibble](#): > > I pronounced the sea creature’s name “sea anna-moan” until I was 10 or so. I thought the French Canadians would meet at the ren dezz-vuss to trade pelts for whiskey. ---
**Author:** ![Teuton](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/teuton/32/3864_2.png) [@Teuton](https://boards.straightdope.com/u/Teuton)\ **Post date:** [November 17, 2019, 10:13am UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/35 "2019-11-17T10:13:58Z")
> [@brossa](#): > > I thought the French Canadians would meet at the ren dezz-vuss to trade pelts for whiskey. I’m still not convinced that “hyperbole” isn’t a practical joke aimed at me. ---
**Author:** ![EdelweissPirate](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@EdelweissPirate](https://boards.straightdope.com/u/EdelweissPirate)\ **Post date:** [November 17, 2019, 8:56pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/36 "2019-11-17T20:56:08Z")
> [@RioRico](#): > > ‘True’ color is like an idealized ‘straight’ line - a theoretical construct only. And it’s not a rigorous construct, either—it can’t be, as “true color” is inherently subjective. I’m red/green colorblind, and the colors I see are objectively different from what non-colorblind people see. And let’s not forget about people with tetrachromacy. > [@Pleonast](#): > > True color photographs of a single object are going to look different depending on time of day, cloud cover, street lights, and so on because a human observer’s perceptions would change. Post and username check out: this is nearly a pleonasm. If “true color” is in the eye of the beholder, then there’s no objective way to say whether a particular image is a “true color” photo. If a true color image is “true color” because the observer judges it so, then that’s a hot buttered tautology. In contrast, false-color images are easy to define. I work with infrared cameras, and these all generate false-color images by definition—humans can’t see in infrared, so we map visible colors (including gray, as in grayscale) onto the infrared data. Satellite photos and photomicrographs often employ false color to give higher contrast to the features of interest. I suspect that the term “true color” emerged as an easier way to say “non-false color.” > [@Pleonast](#): > > I’m sorry I can’t go into specific details. I don’t do calibrations myself. The sensitivities of the human eye is fairly well characterized. The sensitivities of various sensors are known as well. It’s a matter of computation to convert from one to the other. The effects of lighting and filters can be included as well. Respectfully, you’re being pretty glib about this—it’s not nearly as straightforward as you describe it. As mentioned above, different human eyes have different spectral response curves—some radically different from others. This is not a simple subject. It’s actually the focus of [a sub-field of philosophy](https://en.wikipedia.org/wiki/Philosophy_of_color). “True color” may be a term of art in whatever field Pleonast toils, but let’s not pretend it’s not jargon. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [February 6, 2020, 4:26pm UTC](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308/37 "2020-02-06T16:26:21Z")
I came across this in a glossary yesterday and was reminded of this thread. > [@](#): > > Handheld photography is not imagery. Yeah, the rabbit hole I work in is very deep. [Previous page](https://boards.straightdope.com/t/what-is-going-on-in-certain-marine-life-photos-in-terms-of-color-mapping-or-saturation/843308.md?page=1)