January 2020 - colorsync-users

RE: Effects of lens implants on color vision (Was RE: Human color vision)
by graxx＠videotron.ca 15 Jan '20

15 Jan '20

Never heard of "UV glasses"? Would anyone have a link? / Roger -----Original Message----- From: colorsync-users <colorsync-users-bounces+graxx=videotron.ca(a)lists.apple.com> On Behalf Of Refik Telhan via colorsync-users Sent: Wednesday, January 15, 2020 11:32 AM To: Wayne Bretl <waynebretl(a)cox.net> Cc: colorsync-users(a)lists.apple.com; graeme(a)argyllcms.com Subject: Re: Effects of lens implants on color vision (Was RE: Human color vision) Hi Wayne, This is the expected behavior. The UV-blocking glasses typically suppress wavelengths below 400 nm. The OBAs in the paper typically emit blue light at 430 nm in response to the UV component of the light at 330 nm. While the glasses block 330 nm, they let the 430 nm and the rest thru. Best, Refik Telhan Light and Color Management consultancy On 15.01.2020 18:35, "colorsync-users on behalf of Wayne Bretl via colorsync-users" <colorsync-users-bounces+rtelhan=icloud.com(a)lists.apple.com on behalf of colorsync-users(a)lists.apple.com> wrote: I just did a little test with brightened and un-brightened paper. Frist, I checked that the glasses do indeed mostly block a UV led flashlight, and start to darken. Then I checked the tint on both papers under fluorescent light with the undarkened lens, and the tint was nearly equally visible to me. -----Original Message----- From: colorsync-users <colorsync-users-bounces+waynebretl=cox.net(a)lists.apple.com> On Behalf Of Graeme Gill via colorsync-users Sent: Tuesday, January 14, 2020 11:54 PM To: colorsync-users(a)lists.apple.com Cc: Graeme Gill <graeme2(a)argyllcms.com> Subject: Re: Effects of lens implants on color vision (Was RE: Human color vision) Wayne Bretl via colorsync-users wrote: > Before I developed cataracts, they appeared to have a slight amber > tint, especially noticeable in natural outdoor light, but also by > placing them on a piece of white paper under artificial light. If the paper was cheap, then this effect may be mostly the lens blocking the UV that triggers the paper Fluorescent Whitening Agent. Graeme Gill. _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/waynebretl%40cox.net This email sent to waynebretl(a)cox.net _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/rtelhan%40icloud.com This email sent to rtelhan(a)icloud.com _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/graxx%40videotron.ca This email sent to graxx(a)videotron.ca

2 1

RE: Human color vision
by graxx＠videotron.ca 15 Jan '20

15 Jan '20

Bob, Call me nuts, but I'm actually looking forward to the day I'll have a cataract removed for the very reason you mention, that experience of looking at the world, all of a sudden, *without* yellow filters. I read the same account as you described, in the color literature, that the sky takes on a stronger vivid shade of blue and so on. All I know about the Standard Observer is that it was made of two groups of men but I have no details on their age... I guess they had "normal color vision" 😊 / Roger -----Original Message----- From: colorsync-users <colorsync-users-bounces+graxx=videotron.ca(a)lists.apple.com> On Behalf Of Bob-BTY via colorsync-users Sent: Tuesday, January 14, 2020 10:42 AM To: colorsync-users(a)lists.apple.com Subject: Human color vision Many people don't seem to know that the lenses in the human eye start going yellow with age. By the age of 50 most people are looking at the world through yellow filters! I experienced this when having a lens replaced because of cataract. The new plastic lens was clear, and when I came out of the operating room, I could see that the dresses of the nurses (that were grey/white stripes before) were now blue/white when I looked at them with the new lens. With the yellow lens in my other eye they were still grey/white! A blue sky was now qite vivid with the new plastic lens, not so with the old yellow lens. I played about with Wratten filters to see how yellow my original lens was, but sadly I can't find the details any more, and nnow have two clear plastic lenses. I wonder how old the 'Standard Observer' was? Bob Frost _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/graxx%40videotron.ca This email sent to graxx(a)videotron.ca

7 6

RE: Human color vision
by graxx＠videotron.ca 15 Jan '20

15 Jan '20

Actually, "violet" is one of my "pet" colors, these days. / Roger -----Original Message----- From: colorsync-users <colorsync-users-bounces+graxx=videotron.ca(a)lists.apple.com> On Behalf Of David Scharf via colorsync-users Sent: Tuesday, January 14, 2020 8:54 PM To: colorsync-users(a)lists.apple.com Cc: David Scharf <electronman(a)roadrunner.com> Subject: Re: Human color vision You'll finally be able to see violet again!!! DAVID SCHARF PHOTOGRAPHY *DAVID SCHARF * On 1/14/20 9:25 AM, Roger Breton via colorsync-users wrote: > Bob, > > Call me nuts, but I'm actually looking forward to the day I'll have a cataract removed for the very reason you mention, that experience of looking at the world, all of a sudden, *without* yellow filters. I read the same account as you described, in the color literature, that the sky takes on a stronger vivid shade of blue and so on. > > All I know about the Standard Observer is that it was made of two groups of men but I have no details on their age... I guess they had "normal color vision" 😊 > > / Roger > > -----Original Message----- > From: colorsync-users <colorsync-users-bounces+graxx=videotron.ca(a)lists.apple.com> On Behalf Of Bob-BTY via colorsync-users > Sent: Tuesday, January 14, 2020 10:42 AM > To: colorsync-users(a)lists.apple.com > Subject: Human color vision > > Many people don't seem to know that the lenses in the human eye start going yellow with age. By the age of 50 most people are looking at the world through yellow filters! I experienced this when having a lens replaced because of cataract. The new plastic lens was clear, and when I came out of the operating room, I could see that the dresses of the nurses (that were grey/white stripes before) were now blue/white when I looked at them with the new lens. With the yellow lens in my other eye they were still grey/white! A blue sky was now qite vivid with the new plastic lens, not so with the old yellow lens. I played about with Wratten filters to see how yellow my original lens was, but sadly I can't find the details any more, and nnow have two clear plastic lenses. I wonder how old the 'Standard Observer' was? > > Bob Frost > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > colorsync-users mailing list (colorsync-users(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/colorsync-users/graxx%40videotron.ca > > This email sent to graxx(a)videotron.ca > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > colorsync-users mailing list (colorsync-users(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/colorsync-users/david%40scharfphoto… > > This email sent to david(a)scharfphoto.com _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/graxx%40videotron.ca This email sent to graxx(a)videotron.ca

1 0

RE: Humans (and cameras and scanners) do not have a color gamut (?)
by graxx＠videotron.ca 15 Jan '20

15 Jan '20

It's an interesting page, Wire -- thank you. Only 23 unique colors? Now that's food for thought... / Roger -----Original Message----- From: colorsync-users <colorsync-users-bounces+graxx=videotron.ca(a)lists.apple.com> On Behalf Of Wire ~ via colorsync-users Sent: Tuesday, January 14, 2020 4:48 PM To: 'colorsync-users?lists.apple.com' List <colorsync-users(a)lists.apple.com> Subject: Re: Humans (and cameras and scanners) do not have a color gamut (?) Searching for layman's info on details of Wright and Guild experiments, I was surprised to find this source. It's webbook that takes on the matters at hand here as related to earth science / oceanography. Ocean Optics Webbook - Photometry and Visibility http://www.oceanopticsbook.info/view/photometry_and_visibility/chromaticity According to the Kelly 1943 projection of the CIE spectrum locus, there are 23 unique colors!

1 0

Human color vision
by Bob-BTY 14 Jan '20

14 Jan '20

Many people don't seem to know that the lenses in the human eye start going yellow with age. By the age of 50 most people are looking at the world through yellow filters! I experienced this when having a lens replaced because of cataract. The new plastic lens was clear, and when I came out of the operating room, I could see that the dresses of the nurses (that were grey/white stripes before) were now blue/white when I looked at them with the new lens. With the yellow lens in my other eye they were still grey/white! A blue sky was now qite vivid with the new plastic lens, not so with the old yellow lens. I played about with Wratten filters to see how yellow my original lens was, but sadly I can't find the details any more, and nnow have two clear plastic lenses. I wonder how old the 'Standard Observer' was? Bob Frost

3 2

RE: Humans (and cameras and scanners) do not have a color gamut (?)
by graxx＠videotron.ca 14 Jan '20

14 Jan '20

I agree, Edmund, this type of discussion is good. The List is awfully quiet these days... / Roger -----Original Message----- From: colorsync-users <colorsync-users-bounces+graxx=videotron.ca(a)lists.apple.com> On Behalf Of edmund ronald via colorsync-users Sent: Wednesday, January 8, 2020 2:13 AM To: Iliah Borg <iliah.i.borg(a)gmail.com> Cc: 'colorsync-users?lists. apple. com' List <colorsync-users(a)lists.apple.com> Subject: Re: Humans (and cameras and scanners) do not have a color gamut (?) BTW I think this type of discussion is quite helpful because it exposes all sorts of computer geeks and photographers who lurk here to the idea that what they are doing is twiddling the buttons on some very cumbersome tech that is quite distant from what humans perceive. This can be demoed easily when one takes a multispectral capture, and suddenly realises that although a lot of information has been stored it is hard to transform this back into valid dense-impressions. Edmund

14 81

is unsubscribing possible?
by tboley＠tylerboley.com 14 Jan '20

14 Jan '20

I've tried multiple times following the instructions here and logging in on the " unsubscribe via the World Wide Web" and completing that, multiple times. I did get an alert there that some higher power is considering my request, that was a while ago... Maybe there was fine print about this following me through my fate in the universe when I subscribed? Anybody know how to do it? Thank you. Tyler

3 2

RE: Humans (and cameras and scanners) do not have a color gamut (?)
by graxx＠videotron.ca 14 Jan '20

14 Jan '20

That's just it, there isn't an "absolute" gamut for a Heidelberg press or any other printing press or any other printing device, as long as, you know, the media and can be changed. I'm not sure this helps... I wonder if my "eyes" have a gamut, the range of all observable visible wavelength radiations? / Roger -----Original Message----- From: colorsync-users <colorsync-users-bounces+graxx=videotron.ca(a)lists.apple.com> On Behalf Of andrew--- via colorsync-users Sent: Tuesday, January 14, 2020 9:21 AM To: Martin Orpen <martin(a)idea-digital.com> Cc: 'colorsync-users?lists.apple.com' List <colorsync-users(a)lists.apple.com> Subject: Re: Humans (and cameras and scanners) do not have a color gamut (?) Andrew Sent from my iPhone > On Jan 14, 2020, at 2:19 AM, Martin Orpen via colorsync-users <colorsync-users(a)lists.apple.com> wrote: > > >> On 14 Jan 2020, at 01:54, Graeme Gill via colorsync-users <colorsync-users(a)lists.apple.com> wrote: >> >> If by "gamut" you mean that they have limits, then yes, input devices >> have limits. Just not of the sort that can be defined by a volume of >> tri-stimulus space. > > > What’s the colour gamut of a 12 colour Heidelberg press then? Upload a press profile and those of us with tools to map color gamut can easily provide a color gamut plot and volume. _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/graxx%40videotron.ca This email sent to graxx(a)videotron.ca

1 0

RE: Humans (and cameras and scanners) do not have a color gamut (?)
by graxx＠videotron.ca 14 Jan '20

14 Jan '20

"There are no facts, only interpretations" -- Nietzsche. I have spoken... / Roger -----Original Message----- From: colorsync-users <colorsync-users-bounces+graxx=videotron.ca(a)lists.apple.com> On Behalf Of John Gnaegy via colorsync-users Sent: Monday, January 13, 2020 9:11 PM To: ColorSync <ColorSync-Users(a)lists.apple.com> Subject: Re: Humans (and cameras and scanners) do not have a color gamut (?) > On Jan 13, 2020, at 6:00 PM, Graeme Gill via colorsync-users <colorsync-users(a)lists.apple.com> wrote: > > You weren't. You came across as attempting to counter the narrative > that everything is relative, and that nothing has meaning, and that there is no such thing as a fact. Whoa whoa whoa... if broadcast and print media have taught us anything it's that all facts are subjective, opinion is just as valid as experimentation, and there is no objective reality. Are you trying to blow my mind, or what? /endSarcasm

1 0

Re: Humans (and cameras and scanners) do not have a color gamut (?)
by Rich Wagner 14 Jan '20

14 Jan '20

This gets a bit off-topic, but it is relevant to the prior discussion and may be of interest to some on this list. > On Mon, 13 Jan 2020 12:52:18 -0500, Henry Davis <davishr(a)bellsouth.net <mailto:davishr@bellsouth.net>>wrote: > > One can find all sorts of expert ?scholarly? work about how animals percieve color. You bring up tetrachromatic, and there are other theories out there about animal perception. They are thrown around as ?facts? when a few decades ago they would have only been counted as speculations. At this point, Henry, you are simply displaying a broad ignorance of science, and in particular, biophysics, which makes further discussion difficult. Yes, there was a lot that was not known about the physiology of “animal vision,” including color perception (and a lot of other science!) decades ago, and much has been learned since then. When I was in grad school working on my PhD in biophysics (electrophysiology), much of the science involving the electrophysiology of photoreception was in its infancy. Neher and Sakmann received the Nobel Prize in 1991 for their development of the “patch clamp” technique that allowed the measurement of femtoamp currents passing through single ion channel molecules in cell walls. I spent more time writing software for data acquisition and analysis and Markov modeling than I did doing experiments. It was a very exciting time during which many of the fundamental mechanisms of cell physiology, photoreception, phototransduction and vision were unraveled. A lot has been learned since then, as the result of a lot of hard, meticulous work by dedicated scientists. Vision is a phenomenally complex process, and although much of it is now fairly well understood and is not controversial, color perception is still an active area of research. Regarding what’s known: there is an excellent online summary of the science behind the organization of the retina here: https://webvision.med.utah.edu/book/part-ii-anatomy-and-physiology-of-the-r… and color vision here: https://webvision.med.utah.edu/book/part-vii-color-vision/color-vision/ and color perception here: https://webvision.med.utah.edu/book/part-viii-psychophysics-of-vision/color… This is not a collection of "a lot of theories being waved around.” This is now scientific consensus. Regarding what’s not known and is currently under investigation, look here: Visual perception - https://www.sciencedirect.com/journal/current-opinion-in-behavioral-science… There are some fascinating articles in this special issue volume, including a review of cone fundamentals and CIE standards. Other articles are mentioned below. The 36 or so articles can be downloaded free. It is accepted fact that color vision processing in the primate visual system is initiated by absorption of light by three different spectral classes of cones. Therefore, color vision is described as being trivariant or trichromatic. You can find graphs of the spectral sensitivities of the S-cone, M-cone, and L-cones online (above). These spectral sensitivities have been measured, they are not hypothetical. If you are colorblind, you do not perceive color as most people do. This is also not controversial. Most colorblindness is due to missing or defective cones. The molecular genetics behind most colorblindness is now also fairly well understood. Tetrameric color vision is not “hypothetical” or “theoretical." There are humans (women) with tetrachromacy, who have a fourth type of cone. To match the sensory effect of arbitrarily chosen spectra of light within their visual spectrum requires mixtures of at least four primary colors. It was once thought that this was exceptionally rare in humans, but that remains an open question. It is certainly not common. (http://www.digitaljournal.com/article/326976, https://www.bbc.com/future/article/20140905-the-women-with-super-human-visi…) There is a great article on tetrachromacy in humans in the volume mentioned above (Tetrachromacy: the mysterious case of extra-ordinary color vision. https://www.sciencedirect.com/journal/current-opinion-in-behavioral-science…) Most birds are known to have retinas with four spectral cone types that mediate tetrachromatic color vision. The fourth cone is variable across avian species, but it primarily detects ultraviolet light. There are also pigmented oil droplets in the photoreceptor cells of birds that filter light before it gets to the outer edge of the cells, that give birds a larger color spectrum than that of humans. To study how birds might use this tetrameric system, the scientists in the article I sent previously created a tetrameric, spectral-based camera that mimicked real animal spectral sensitivities that allowed them to visualize the raw data that would be collected by photoreceptors. This cutting edge research was published in one of the most respected scientific journals in the world. (https://www.nature.com/articles/s41467-018-08142-5) In this era where there has been a great loss of respect for science, and tons of misinformation and false information spread across the internet, I think it is important to remain grounded on the scientific basis of our understanding of the world. Engineers certainly will, as even the avian research described above could be useful in designing sensors with better detection abilities for collision avoidance systems on vehicles, and so on. Understanding and modeling the world around us has been, and will continue to be, the basis for a lot of innovation. —Rich

3 2