Re: Humans (and cameras and scanners) do not have a color gamut (?)
Re: Humans (and cameras and scanners) do not have a color gamut (?)
- Subject: Re: Humans (and cameras and scanners) do not have a color gamut (?)
- From: Wire ~ via colorsync-users <email@hidden>
- Date: Tue, 7 Jan 2020 14:19:54 -0800
The point about there "cameras not having gamut" is another
priestly proclamation.
There's some mysterious divine liminal gate inside the device where a
miracle occurs and light becomes a color. Wait, there is no color except in
the eye of God.
Srsly, a camera emits image data according to a format. The format
determines the range of mapping of the input scene. It's referred through
lots of levels of indirection but basically pops out as say an sRGB JPEG.
What is the camera's gamut in such case. You will not be wrong in my book
to say that it's sRGB. In fact if you try to tell me otherwise, I'll wonder
why you're parsing. You may have a very good reason for parsing. But don't
just assume it's the school of you. (If you're me, you're are trying to
suss out what I know so you can see if you can learn anything, so actually
it is the school of me :)
Sure, you can do anything you want with the image data. Apple likes it when
it overflows your iPhone and makes you go back and buy one with more gigs,
even as most pictures are looked at once then forgotten forever. Except in
Google—they remember.
You will not be wrong to say that the camera (in its mode) has an sRGB
gamut any moreso than you would be wrong to say that sRGB 128,128,128 is a
color, with degrees of uncertainty of presentation (is the display
unplugged) or the brightness turned all the way up, or the wrong profile
loaded in the OS, etc, whatever.
I see that if you are teaching, you need to break this stuff down and help
initiates overcome unquestioned assumptions, so that you can build it back
up in a proper structure that avoids contradictions and confronts lore, and
the teacher becomes the student, and the sound of one hand clapping.
Ordinary users may or may not struggle with this stuff intellectually, but
they for sure struggle with it pragmatically because the tools are so hard
to use and always going wrong! Try giving a teenager a camera and telling
them they need to whoaa! slow down and not get ahead of themselves until
they understand that a "camera has no gamut." They will become so excited
about photography! And maybe become grad students.
/wire
On Tue, Jan 7, 2020 at 1:56 PM Roger Breton via colorsync-users <
email@hidden> wrote:
> Henry,
>
> I'm not a digital camera designer but what don't you understand about the
> fact that a camera is a sophisticated "light detection system"? It's pretty
> much a color measuring instrument (others could correct me) but an i1pro
> does not have a "gamut" per se or a filter-based colorimeter, they take
> light in and spit out numbers in response -- same with digital cameras,
> they take light in and spit out sets of RGB numbers. Surely there's a lot
> of math going on inside the CPU of a Nikon or a Canon or a SONY camera,
> like estimation of scene illuminant by which tonal responses are likely
> adjusted. There may very well be some kind of "model" of various 'natural
> scenes' because, just like during the creation of output profiles, it helps
> to have some kind of "assumptions" as to what ranges of colors or
> luminances are to be expected. But is that a"gamut" per se? A gamut is a
> physical construct, it comes from something measurable that have "limits".
>
> I hope that helps...
>
> / Roger
>
> -----Original Message-----
> From: colorsync-users <colorsync-users-bounces+graxx=
> email@hidden> On Behalf Of Henry Davis via colorsync-users
> Sent: Tuesday, January 7, 2020 4:45 PM
> To: email@hidden
> Subject: Re: Humans (and cameras and scanners) do not have a color gamut
> (?)
>
> When the “cameras absolutely do not have gamuts” quote moves from “some
> response” of a camera to “color accuracy” I get lost. It sounds as though
> there is a ruler(the display) measuring a non-dimensional entity for
> accuracy.
>
> The quote seems to assume that the camera has infinite perfection but it’s
> up to some mysterious other entity to prove that it doesn’t have infinite
> perfection.
>
> I’m now losing my fight to understand - I was pretty much following the
> previous threads about the distinction between color and numbers but this
> curve ball has me swinging and missing. I believe the quote was supposed
> to bring some clarity but it didn’t work for me. Maybe there’s another way
> to explain not having a gamut that will help.
>
> Henry Davis
>
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