Re: Humans (and cameras and scanners) do not have a color gamut (?)
I agree with Florian’s responses below regarding how we “know” what animals “see.” The parallel question is how we “know” what women with tetrachromatic vision “see.” There is a very good article from the BBC that describes this that might help. https://www.bbc.com/future/article/20140905-the-women-with-super-human-visio... Here’s a short excerpt from the excellent story: Proving that these people actually see the world differently has involved a two-decade journey, however. Although the relevant combination of genes does not seem to be especially rare – perhaps 12% of women might have four distinct cones – many of the people that Jordan tested just didn’t seem to show any differences in their perception. But by 2010, she had found a subject who perfectly acted the part of a tetrachromat. Jordan’s “acid test” involved coloured discs showing different mixtures of pigment, such as a green made of yellow and blue. The mixtures were too subtle for most people to notice: almost all people would see the same shade of olive green, but each combination should give out a subtly different spectrum of light that would be perceptible to someone with a fourth cone. Sure enough, Jordan’s subject was able to differentiate between the different mixtures each time <http://www.journalofvision.org/content/10/8/12.full>. “When you ask them to discriminate between the two mixtures, a tetrachromat can do it very quickly. They don’t hesitate,” says Jordan. Unfortunately, much of the research in color perception is highly complex and often difficult for the lay public to comprehend. Good science writers can translate that research into language the lay public can understand. Poor science writing leads to exaggerated claims and misinformation. That said, the title of this article is a bit over the top. I don’t think these women have “super human vision” any more than those who are colorblind have “sub human vision.” Both have visual perception that is significantly different from the average of our species. —Rich
OnMon, 13 Jan 2020 19:40:11 +0100, Florian Hoech <lists+colorsync-users@hoech.org <mailto:lists+colorsync-users@hoech.org>> wrote:
[snip]
Not a single case can be made by anyone?s fisthand information about the post processing by the brains of these animals. Who can know what they see or apprehend?
You can draw pretty useful conclusions (meaning they work well in real-life, thus supporting the respective theories) from all the scientific research that has been done. "Color" perception is not just "nice to have". Trichromats (like humans) have an evolutionary edge over (say) dichromats, e.g. when it comes to distinguish edible/nutritious from inedible/less nutritious food like fruits etc. When you look at the M and L cone responses of any trichromat, you can see that the responses of the "sensors" (cones) largely overlap. Yet, we seem to perceive the "end result", green and red, as very different colors (opposites even!).
Since humans communicate with each other about color we can build models and references and so on. But animals? Yet, experts are quick to supply examples of how things must appear to non-humans.
I think you may be conflating the actual research with how it is presented (usually not by the researchers themselves), broken down and simplified in newspapers/magazines/articles, online and offline, meant for consumption by the general public.
When we grant that all of these theories are onto something about the ways animals percieve color we account for their differences by describing them in terms of ?gamuts?.
I like the term "dimensions". A Tetrachromat has an additional dimension of "color".
Surprise: experts determine gamuts based on the sensor alone! They don?t even seem to be the slightest bit unhappy about it.
...where? And who? Dimensionality alone doesn't really tell us much about gamuts.
Florian.
I'm puzzled as to why no one has constructed a five-wavelength anomaloscope to research tetrachromacy. It seems to me that red, yellow, green, cyan, and blue LEDs are available that could be used in such a device. -----Original Message----- From: colorsync-users <colorsync-users-bounces+waynebretl=cox.net@lists.apple.com> On Behalf Of Rich Wagner via colorsync-users Sent: Monday, January 13, 2020 5:01 PM To: colorsync-users@lists.apple.com Subject: Re: Humans (and cameras and scanners) do not have a color gamut (?) I agree with Florian’s responses below regarding how we “know” what animals “see.” The parallel question is how we “know” what women with tetrachromatic vision “see.” There is a very good article from the BBC that describes this that might help. https://www.bbc.com/future/article/20140905-the-women-with-super-human-visio... Here’s a short excerpt from the excellent story: Proving that these people actually see the world differently has involved a two-decade journey, however. Although the relevant combination of genes does not seem to be especially rare – perhaps 12% of women might have four distinct cones – many of the people that Jordan tested just didn’t seem to show any differences in their perception. But by 2010, she had found a subject who perfectly acted the part of a tetrachromat. Jordan’s “acid test” involved coloured discs showing different mixtures of pigment, such as a green made of yellow and blue. The mixtures were too subtle for most people to notice: almost all people would see the same shade of olive green, but each combination should give out a subtly different spectrum of light that would be perceptible to someone with a fourth cone. Sure enough, Jordan’s subject was able to differentiate between the different mixtures each time <http://www.journalofvision.org/content/10/8/12.full>. “When you ask them to discriminate between the two mixtures, a tetrachromat can do it very quickly. They don’t hesitate,” says Jordan. Unfortunately, much of the research in color perception is highly complex and often difficult for the lay public to comprehend. Good science writers can translate that research into language the lay public can understand. Poor science writing leads to exaggerated claims and misinformation. That said, the title of this article is a bit over the top. I don’t think these women have “super human vision” any more than those who are colorblind have “sub human vision.” Both have visual perception that is significantly different from the average of our species. —Rich
OnMon, 13 Jan 2020 19:40:11 +0100, Florian Hoech <lists+colorsync-users@hoech.org <mailto:lists+colorsync-users@hoech.org>> wrote:
[snip]
Not a single case can be made by anyone?s fisthand information about the post processing by the brains of these animals. Who can know what they see or apprehend?
You can draw pretty useful conclusions (meaning they work well in real-life, thus supporting the respective theories) from all the scientific research that has been done. "Color" perception is not just "nice to have". Trichromats (like humans) have an evolutionary edge over (say) dichromats, e.g. when it comes to distinguish edible/nutritious from inedible/less nutritious food like fruits etc. When you look at the M and L cone responses of any trichromat, you can see that the responses of the "sensors" (cones) largely overlap. Yet, we seem to perceive the "end result", green and red, as very different colors (opposites even!).
Since humans communicate with each other about color we can build models and references and so on. But animals? Yet, experts are quick to supply examples of how things must appear to non-humans.
I think you may be conflating the actual research with how it is presented (usually not by the researchers themselves), broken down and simplified in newspapers/magazines/articles, online and offline, meant for consumption by the general public.
When we grant that all of these theories are onto something about the ways animals percieve color we account for their differences by describing them in terms of ?gamuts?.
I like the term "dimensions". A Tetrachromat has an additional dimension of "color".
Surprise: experts determine gamuts based on the sensor alone! They don?t even seem to be the slightest bit unhappy about it.
...where? And who? Dimensionality alone doesn't really tell us much about gamuts.
Florian.
_______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/waynebretl%40cox.net This email sent to waynebretl@cox.net
On Jan 13, 2020, at 5:12 PM, Wayne Bretl <waynebretl@cox.net> wrote:
I'm puzzled as to why no one has constructed a five-wavelength anomaloscope to research tetrachromacy. It seems to me that red, yellow, green, cyan, and blue LEDs are available that could be used in such a device.
Great question! While genetic testing shows the potential for tetrachromacy, the proof is in the functional studies. TETRACHROMATIC COLOR VISION http://www.imbs.uci.edu/~kjameson/jamesonOUP3.pdf The Veridicality of Color: A case study of potential human tetrachromacy. https://www.imbs.uci.edu/research/MBS14-02.pdf Genetic testing: Participant CA was color vision genotype assessed in 2012 by an independent research laboratory which stated CA has the genes for retinal tetrachromacy. Specifically, CA’s gene sequence for long-wavelength (L-) sensitive type cells shows an Exon 3 codon 180 polymorphism in the nucleotide sequence of her L-cone opsin gene electropherogram (personal communication from Concetta Antico, May 28, 2014). CA’s genotype results are at http:// concettaantico.com/scientific-details/. CA was featured in a Fuji Television Documentary entitled “Science Mysteries” that aired in June 2013 (see http://www.youtube.com/watch? v=D9Eamc4JV9A). Future genetic analyses will confirm or qualify these results, and explore additional photopigment opsin allelic variations CA may possess. See also: Human Tetrachromacy Research Collaborative (http://tenthousandthings.info/) a multidisciplinary group of researchers investigating the molecular genetic, perceptual, behavioral and applied aspects of potential human tetrachromacy -Rich
Thanks! From: Rich Wagner <Rich@WildNaturePhotos.com> Sent: Monday, January 13, 2020 6:07 PM To: colorsync-users@lists.apple.com Cc: Wayne Bretl <waynebretl@cox.net> Subject: Re: Humans (and cameras and scanners) do not have a color gamut (?) On Jan 13, 2020, at 5:12 PM, Wayne Bretl <waynebretl@cox.net <mailto:waynebretl@cox.net> > wrote: I'm puzzled as to why no one has constructed a five-wavelength anomaloscope to research tetrachromacy. It seems to me that red, yellow, green, cyan, and blue LEDs are available that could be used in such a device. Great question! While genetic testing shows the potential for tetrachromacy, the proof is in the functional studies. TETRACHROMATIC COLOR VISION http://www.imbs.uci.edu/~kjameson/jamesonOUP3.pdf The Veridicality of Color: A case study of potential human tetrachromacy. https://www.imbs.uci.edu/research/MBS14-02.pdf Genetic testing: Participant CA was color vision genotype assessed in 2012 by an independent research laboratory which stated CA has the genes for retinal tetrachromacy. Specifically, CA’s gene sequence for long-wavelength (L-) sensitive type cells shows an Exon 3 codon 180 polymorphism in the nucleotide sequence of her L-cone opsin gene electropherogram (personal communication from Concetta Antico, May 28, 2014). CA’s genotype results are at http:// concettaantico.com/scientific-details/ <http://concettaantico.com/scientific-details/> . CA was featured in a Fuji Television Documentary entitled “Science Mysteries” that aired in June 2013 (see http://www.youtube.com/watch? v=D9Eamc4JV9A). Future genetic analyses will confirm or qualify these results, and explore additional photopigment opsin allelic variations CA may possess. See also: Human Tetrachromacy Research Collaborative (http://tenthousandthings.info/) a multidisciplinary group of researchers investigating the molecular genetic, perceptual, behavioral and applied aspects of potential human tetrachromacy -Rich
I’ll check it out but your excerpt appears to mention people only. Eyes as ‘sensors’ have been described by scientists as having limits or gamuts. They also use visual aides to help illustrate distinctions for how different animals see. This, for me, is speculation. The threads I’ve been reading here have insisted that sensors do not have gamuts. No one has yet to clear up this contradiction. Florian makes some good points but the idea that certain kinds of vision help in certain circumstances doesn’t offer much in the way of telling us what a non human actually sees. Henry Davis
On Jan 13, 2020, at 7:00 PM, Rich Wagner via colorsync-users <colorsync-users@lists.apple.com> wrote:
I agree with Florian’s responses below regarding how we “know” what animals “see.” The parallel question is how we “know” what women with tetrachromatic vision “see.”
There is a very good article from the BBC that describes this that might help.
https://www.bbc.com/future/article/20140905-the-women-with-super-human-visio...
Here’s a short excerpt from the excellent story:
Proving that these people actually see the world differently has involved a two-decade journey, however. Although the relevant combination of genes does not seem to be especially rare – perhaps 12% of women might have four distinct cones – many of the people that Jordan tested just didn’t seem to show any differences in their perception. But by 2010, she had found a subject who perfectly acted the part of a tetrachromat. Jordan’s “acid test” involved coloured discs showing different mixtures of pigment, such as a green made of yellow and blue. The mixtures were too subtle for most people to notice: almost all people would see the same shade of olive green, but each combination should give out a subtly different spectrum of light that would be perceptible to someone with a fourth cone. Sure enough, Jordan’s subject was able to differentiate between the different mixtures each time <http://www.journalofvision.org/content/10/8/12.full>. “When you ask them to discriminate between the two mixtures, a tetrachromat can do it very quickly. They don’t hesitate,” says Jordan.
Unfortunately, much of the research in color perception is highly complex and often difficult for the lay public to comprehend. Good science writers can translate that research into language the lay public can understand. Poor science writing leads to exaggerated claims and misinformation. That said, the title of this article is a bit over the top. I don’t think these women have “super human vision” any more than those who are colorblind have “sub human vision.” Both have visual perception that is significantly different from the average of our species.
—Rich
OnMon, 13 Jan 2020 19:40:11 +0100, Florian Hoech <lists+colorsync-users@hoech.org <mailto:lists+colorsync-users@hoech.org>> wrote:
[snip]
Not a single case can be made by anyone?s fisthand information about the post processing by the brains of these animals. Who can know what they see or apprehend?
You can draw pretty useful conclusions (meaning they work well in real-life, thus supporting the respective theories) from all the scientific research that has been done. "Color" perception is not just "nice to have". Trichromats (like humans) have an evolutionary edge over (say) dichromats, e.g. when it comes to distinguish edible/nutritious from inedible/less nutritious food like fruits etc. When you look at the M and L cone responses of any trichromat, you can see that the responses of the "sensors" (cones) largely overlap. Yet, we seem to perceive the "end result", green and red, as very different colors (opposites even!).
Since humans communicate with each other about color we can build models and references and so on. But animals? Yet, experts are quick to supply examples of how things must appear to non-humans.
I think you may be conflating the actual research with how it is presented (usually not by the researchers themselves), broken down and simplified in newspapers/magazines/articles, online and offline, meant for consumption by the general public.
When we grant that all of these theories are onto something about the ways animals percieve color we account for their differences by describing them in terms of ?gamuts?.
I like the term "dimensions". A Tetrachromat has an additional dimension of "color".
Surprise: experts determine gamuts based on the sensor alone! They don?t even seem to be the slightest bit unhappy about it.
...where? And who? Dimensionality alone doesn't really tell us much about gamuts.
Florian.
_______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/davishr%40bellsouth....
This email sent to davishr@bellsouth.net
Henry Davis via colorsync-users wrote:
The threads I’ve been reading here have insisted that sensors do not have gamuts. No one has yet to clear up this contradiction.
That topic has been cleared up over and over again. I'm not sure that repeating the information will improve comprehension, but here's another short summary: If by "gamut" you mean a well defined volume of tri-stimulus space, then no, input devices don't have gamuts. This is due to the nature of the many-to-one spectral to tri-stimulus transform that they perform allowing for colors that can be be accurately captured if having one spectra, but not being accurately captured if they have another. 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. That's it. You can stop wondering if sensors have gamuts. Graeme Gill.
In original context the point was about cameras having gamuts, where the definition of a camera was left open-ended but reasonably interpretable in context as a modern digicam. This got distorted into a point about sensors where the distinction and ambiguity could be exploited rhetorically. Eventually the original context was ejected, partly because rhetorically it didn't suit a certain power dynamic and partly because of a resort to ad hominem tactics. Fair minded observers saw this and chimed in to recenter the conversation and explore their own ideas about how to think about the subject. And here we are. I apologize for feeding the flames. Carry on peoplez! On Mon, Jan 13, 2020 at 17:54 Graeme Gill via colorsync-users < colorsync-users@lists.apple.com> wrote:
Henry Davis via colorsync-users wrote:
The threads I’ve been reading here have insisted that sensors do not have gamuts. No one has yet to clear up this contradiction.
That topic has been cleared up over and over again. I'm not sure that repeating the information will improve comprehension, but here's another short summary:
If by "gamut" you mean a well defined volume of tri-stimulus space, then no, input devices don't have gamuts. This is due to the nature of the many-to-one spectral to tri-stimulus transform that they perform allowing for colors that can be be accurately captured if having one spectra, but not being accurately captured if they have another.
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.
That's it. You can stop wondering if sensors have gamuts.
Graeme Gill. _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/colorsync-users/wire%40lexiphanicism...
This email sent to wire@lexiphanicism.com
It’s really a pity, calling people names and ridiculing them as ignorant. You’d think such ‘educated’ people would have learned a thing or two about that. Some of these ignorant people are quite thoughtful with their comments and heaven forbid some of them may even be credentialed as well. With all of the back and forth I’m still not convinced that, within ordinary usage, a sensor doesn’t have a gamut. Now, if you take gamut to mean some specialized, non ordinary meaning and usage then I suppose bounds and limits can’t be described as gamuts under those restrictions. I’m ok with that if at least once somebody would admit to a special use of the word. It’s actually laughingly funny that nobody has yet admitted that they have a special, unique definition of gamut - and that they own it! Actually, the rest of it, the name-calling and snarkiness, is funny too. The ignorance that generates it must be powerful. Sadly, defensiveness can reach a level that might be called clinical (using a specialized definition of course). Exchaning ideas is often fun and enlightening - as some of this has been for me. I’ve picked up some ideas here that have caused me to think about things a little differently even though I’m still unconvinced. That might be progress. Henry Davis
On Jan 13, 2020, at 9:09 PM, Wire ~ via colorsync-users <colorsync-users@lists.apple.com> wrote:
In original context the point was about cameras having gamuts, where the definition of a camera was left open-ended but reasonably interpretable in context as a modern digicam.
This got distorted into a point about sensors where the distinction and ambiguity could be exploited rhetorically.
Eventually the original context was ejected, partly because rhetorically it didn't suit a certain power dynamic and partly because of a resort to ad hominem tactics. Fair minded observers saw this and chimed in to recenter the conversation and explore their own ideas about how to think about the subject.
And here we are.
I apologize for feeding the flames.
Carry on peoplez!
On Jan 13, 2020, at 7:47 PM, Henry Davis via colorsync-users <colorsync-users@lists.apple.com> wrote:
It’s really a pity, calling people names and ridiculing them as ignorant.
With all of the back and forth I’m still not convinced that, within ordinary usage, a sensor doesn’t have a gamut.
With incorrect usage and by utterly ignoring those color experts in the field, now at least half a dozen if not more, YES, a sensor doesn’t have a color gamut. And that should make perfect sense if you suspend all rational and scientific thought. “The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.” ― Daniel J. Boorstin
Using Catalina. Used to be able to print without color management. Can’t find any settings that make the “Print as Target: dropdown option not grayed out. Bug or I’m missing something? TIA Andrew Rodney http://www.digitaldog.net/ <http://www.digitaldog.net/>
Bug it seems. One must go into Color Matching and ensure that Automatic IS NOT selected. Select a profile, any profile, pick sRGB as an example. Go back to ColorSync Utility part of the GUI in that dropdown, now and only now can one select “Print as Target”. If Automatic is selected, you cannot select this as an option. And another part of the bug, go back to Color Matching, both ratio buttons are now grayed out. Makes no sense to me I have to ‘assign’ a profile to get Print as Target to work but that’s the magic trick in Catalina.
On Jul 6, 2020, at 7:58 AM, Andrew Rodney via colorsync-users <colorsync-users@lists.apple.com> wrote:
Using Catalina. Used to be able to print without color management. Can’t find any settings that make the “Print as Target: dropdown option not grayed out. Bug or I’m missing something?
TIA
Andrew Rodney http://www.digitaldog.net/ <http://www.digitaldog.net/>
Is not a gamut a limit? Restricting gamut to certain coordinte systems doesn’t make it any less a limit. Restricting ‘gamut’ to a jargon definition doesn’t erradicate ‘gamut’ as an applicable term for describing color bounds or capabilities. Gamut is a broader term than it has been reduced to by some in this thread. Sorry if this doesn’t fit the model for some color scientists but that’s the way it goes. If a group wants to own language then they’re bound to run into ignorant people like me. It’s the price you pay for ownership. Henry Davis
On Jan 13, 2020, at 8:54 PM, Graeme Gill via colorsync-users <colorsync-users@lists.apple.com> wrote:
Henry Davis via colorsync-users wrote:
The threads I’ve been reading here have insisted that sensors do not have gamuts. No one has yet to clear up this contradiction.
That topic has been cleared up over and over again. I'm not sure that repeating the information will improve comprehension, but here's another short summary:
If by "gamut" you mean a well defined volume of tri-stimulus space, then no, input devices don't have gamuts. This is due to the nature of the many-to-one spectral to tri-stimulus transform that they perform allowing for colors that can be be accurately captured if having one spectra, but not being accurately captured if they have another.
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.
That's it. You can stop wondering if sensors have gamuts.
Graeme Gill.
On Jan 13, 2020, at 7:14 PM, Henry Davis via colorsync-users <colorsync-users@lists.apple.com> wrote:
Is not a gamut a limit?
The discussion here is color gamut. Color gamut defines a range of colors. Even more specifically (not that it should be necessary after so many days of this) but one more example: https://color.viewsonic.com/explore/content/Color-gamut_6.html “The color gamut describes a range of color within the spectrum of colors that are identifiable by the human eye (visible color spectrum)“.
Restricting gamut to certain coordinte systems doesn’t make it any less a limit. Restricting ‘gamut’ to a jargon definition doesn’t erradicate ‘gamut’ as an applicable term for describing color bounds or capabilities.
Color gamut has a limit based on what is and isn’t color. Absolutely not joking and fact: I had a dog who’s name was Gamut. He had absolutely nothing to do with color gamut.
Gamut is a broader term than it has been reduced to by some in this thread.
We don’t need a broader term for color gamut, just color gamut and it’s well established and excepted (by most) definition. There’s yet another above.
Sorry if this doesn’t fit the model for some color scientists but that’s the way it goes.
Many color scientists have stated the facts about color gamut and the lack thereof from input devices like digital cameras.
If a group wants to own language then they’re bound to run into ignorant people like me. It’s the price you pay for ownership.
I don’t speak for the group or anyone but myself but you'll hear some posters speak for others. I am very clear on my understanding on color gamut because my understanding comes from a pretty significant number of color scientists and experts and all agree; I’ve copied and pasted their text which, much of which was paramount in my understanding of color gamut. Unlike just a few here, disagreeing with so many esteemed and well respected experts on color is way over my pay grade. I absolutely agree with Graeme: That topic has been cleared up over and over again. Andrew Rodney http://www.digitaldog.net/ <http://www.digitaldog.net/>
Henry Davis
On Jan 13, 2020, at 8:54 PM, Graeme Gill via colorsync-users <colorsync-users@lists.apple.com> wrote:
Henry Davis via colorsync-users wrote:
The threads I’ve been reading here have insisted that sensors do not have gamuts. No one has yet to clear up this contradiction.
That topic has been cleared up over and over again. I'm not sure that repeating the information will improve comprehension, but here's another short summary:
If by "gamut" you mean a well defined volume of tri-stimulus space, then no, input devices don't have gamuts. This is due to the nature of the many-to-one spectral to tri-stimulus transform that they perform allowing for colors that can be be accurately captured if having one spectra, but not being accurately captured if they have another.
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.
That's it. You can stop wondering if sensors have gamuts.
Graeme Gill.
_______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/andrew%40digitaldog....
This email sent to andrew@digitaldog.net
On 14 Jan 2020, at 01:54, Graeme Gill via colorsync-users <colorsync-users@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? -- Martin Orpen Idea Digital Imaging Ltd
Martin Orpen via colorsync-users wrote:
What’s the colour gamut of a 12 colour Heidelberg press then?
I'm not sure how that's relevant, but it's easy enough to find out - profile it and then see what color volume the resulting profile can reach. Cheers, Graeme Gill.
On 14 Jan 2020, at 11:36, Graeme Gill via colorsync-users <colorsync-users@lists.apple.com> wrote:
Martin Orpen via colorsync-users wrote:
What’s the colour gamut of a 12 colour Heidelberg press then?
I'm not sure how that's relevant, but it's easy enough to find out - profile it and then see what color volume the resulting profile can reach.
How can you profile it? We have coatings that are only visible to humans under specific illuminants, coatings that change colour dependent on temperature, coatings that fluoresce, coatings that are magnetic etc etc. If I can run any known coating to any known substrate then the output device would become as difficult to profile as an input device wouldn’t it? -- Martin Orpen Idea Digital Imaging Ltd
Martin Orpen via colorsync-users wrote:
How can you profile it?
Like any other output device!
We have coatings that are only visible to humans under specific illuminants, coatings that change colour dependent on temperature, coatings that fluoresce, coatings that are magnetic etc etc.
As you well know, you need special instruments to characterize optical properties other than color. If you load a printer up with inks that have such special characteristics, then using conventional color measurement is unlikely to be a good characterization of its appearance or other physical characteristics. So this is all irrelevant to the discussion, since it strays outside the realm of spectral characteristics and color.
If I can run any known coating to any known substrate then the output device would become as difficult to profile as an input device wouldn’t it?
No, it would be more difficult. An input device can be characterized measuring its spectral sensitivity. Cheers, Graeme Gill.
Andrew Sent from my iPhone
On Jan 14, 2020, at 2:19 AM, Martin Orpen via colorsync-users <colorsync-users@lists.apple.com> wrote:
On 14 Jan 2020, at 01:54, Graeme Gill via colorsync-users <colorsync-users@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.
On Jan 14, 2020, at 2:18 AM, Martin Orpen via colorsync-users <colorsync-users@lists.apple.com> wrote:
What’s the colour gamut of a 12 colour Heidelberg press then?
Go get the ICC press profile. Those of us with the software tools to plot the color gamut and gamut volume of ICC output profiles *may* be happy to show you the color gamut of such output devices. How do you assume the output color space for such a press is produced in the first place???? Andrew Rodney http://www.digitaldog.net/ <http://www.digitaldog.net/>
participants (8)
-
Andrew Rodney
-
andrew＠digitaldog.net
-
Graeme Gill
-
Henry Davis
-
Martin Orpen
-
Rich Wagner
-
Wayne Bretl
-
Wire ~