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why device independent color?

 
 
Dale
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      01-23-2014
if you want to purpose an image to more than one output device color,
and have the output look the same

or

if you want different input device color purposed to different output
device color(s) and want the output to look the same

then

you need to convert the device colors through device independent color
space like XYZ,CIELAB,CIELUV

I remember the introduction of the sRGB standard color space

I remember speaking on Kodak's internal ICC ( http://www.color.org )
mailing list, espousing that sRGB would be an excuse NOT to make device
profiles with regard to the device independent color space(s)

I think the use of SWOP CMYK standards had a similar result

it's been almost 20 years and it seems like most cameras are using sRGB
or ProPhotoRGB as default profiles instead of getting a REAL profile
from the vendor of the hardware or making such a profile itself

people who don't consider how far an image accurately when it is
multi-purposed in device independent color

there are few vertical imaging workflows left, perhaps there you can
translate the color by matching filtration, etc.

the only place I see for sRGB and SWOP is consumer related imaging

not to say that RGB/CMY (with/without maintenance of black channel)
isn't the best working space, I just don't see it as a profile
connection space, since there are MANY RGBs, they are device dependent,
and have device dependent color, whereas XYZ,CIELAB,CIELUV are
independent of device

let me take this time to also say that the print reference medium has
been a start with ICC to tackle appearance matching instead of color
matching, ought to be more reference mediums and implementations of such
use-cases to make better workflows


--
Dale
 
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nospam
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      01-23-2014
In article <(E-Mail Removed)>, Dale
<(E-Mail Removed)> wrote:

> if you want to purpose an image to more than one output device color,
> and have the output look the same
>
> or
>
> if you want different input device color purposed to different output
> device color(s) and want the output to look the same
>
> then
>
> you need to convert the device colors through device independent color
> space like XYZ,CIELAB,CIELUV


completely wrong.

what is needed is a colour managed workflow, with the image and each
device along the way having a profile.
 
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nospam
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      01-24-2014
In article <(E-Mail Removed)>, Eric Stevens
<(E-Mail Removed)> wrote:

> >> if you want to purpose an image to more than one output device color,
> >> and have the output look the same
> >>
> >> or
> >>
> >> if you want different input device color purposed to different output
> >> device color(s) and want the output to look the same
> >>
> >> then
> >>
> >> you need to convert the device colors through device independent color
> >> space like XYZ,CIELAB,CIELUV

> >
> >completely wrong.
> >
> >what is needed is a colour managed workflow, with the image and each
> >device along the way having a profile.

>
> And how do you do that with a reference colour space, such as "XYZ,
> CIELAB, CIELUV"?


users do not need to convert the image.

what they need to do is use a colour managed workflow and the computer
takes care of the details.

if you choose a different printer, pick the relevant profile and
whatever conversions are necessary are done automatically.

once again, let the computer do the work.
 
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Dale
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      01-24-2014
On 01/23/2014 10:06 PM, nospam wrote:
> once again, let the computer do the work.


no, let lab dudes do gamut compression math, etc., by hand, for each image

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Dale
 
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Dale
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      01-24-2014
On 01/23/2014 04:52 PM, nospam wrote:
> In article <(E-Mail Removed)>, Dale
> <(E-Mail Removed)> wrote:
>
>> if you want to purpose an image to more than one output device color,
>> and have the output look the same
>>
>> or
>>
>> if you want different input device color purposed to different output
>> device color(s) and want the output to look the same
>>
>> then
>>
>> you need to convert the device colors through device independent color
>> space like XYZ,CIELAB,CIELUV

>
> completely wrong.
>
> what is needed is a colour managed workflow, with the image and each
> device along the way having a profile.
>


that's how you get the profiles

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Dale
 
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Dale
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      01-24-2014
On 01/24/2014 04:25 AM, Eric Stevens wrote:
> On Thu, 23 Jan 2014 22:06:42 -0500, nospam <(E-Mail Removed)>
> wrote:
>
>> In article <(E-Mail Removed)>, Eric Stevens
>> <(E-Mail Removed)> wrote:
>>
>>>>> if you want to purpose an image to more than one output device color,
>>>>> and have the output look the same
>>>>>
>>>>> or
>>>>>
>>>>> if you want different input device color purposed to different output
>>>>> device color(s) and want the output to look the same
>>>>>
>>>>> then
>>>>>
>>>>> you need to convert the device colors through device independent color
>>>>> space like XYZ,CIELAB,CIELUV
>>>>
>>>> completely wrong.
>>>>
>>>> what is needed is a colour managed workflow, with the image and each
>>>> device along the way having a profile.
>>>
>>> And how do you do that with a reference colour space, such as "XYZ,
>>> CIELAB, CIELUV"?

>>
>> users do not need to convert the image.
>>
>> what they need to do is use a colour managed workflow and the computer
>> takes care of the details.
>>
>> if you choose a different printer, pick the relevant profile and
>> whatever conversions are necessary are done automatically.
>>
>> once again, let the computer do the work.

>
> But the computer has to have some standards against which it can
> determine the meaning of the colour profile. Otherwise its a bit like
> saying to your tailor I want a 197 chest, a 132 waist and a leg of
> 106. At which point your tailor will say "Huh! Waddaya mean?".
>


profiles are calculated to go from device space to device independent
space, or vice versa

there are other considerations ...

but sRGB or SWOP or ProPhotoRGB are NOT device independent color spaces,
they are device standard spaces with which to match by design of
equipment/media to such device standard space

like a TV and a TV Camera, or like consumer imaging nowadays

even those might want to repurpose the image outside such a chain, in
which case you need to go through a device independent space with a profile

with all the different things happening in television besides P22 and
EBU phosphor CRT display, there are LCD, LED, Plasma, OLED, maybe more,
I think sRGB is going to die, same with ProphotoRGB and like SWOP
already might have

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Dale
 
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nospam
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      01-24-2014
In article <(E-Mail Removed)>, Dale
<(E-Mail Removed)> wrote:

> > once again, let the computer do the work.

>
> no, let lab dudes do gamut compression math, etc., by hand, for each image


what lab dudes? what labs?

people process their own images on their own computers, and all they
need to do is adopt a colour managed workflow and let the computer do
the work.

there is no need to do the math by hand for each image.
 
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nospam
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      01-24-2014
In article <(E-Mail Removed)>, Dale
<(E-Mail Removed)> wrote:

> >
> > what is needed is a colour managed workflow, with the image and each
> > device along the way having a profile.
> >

> that's how you get the profiles


no, you get the profiles by running the appropriate profiling software.

what the software does internally doesn't matter. users do not need to
understand all the math behind it to be able to use it.

what matters is does the user get what they expect, and the answer is
yes.
 
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nospam
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      01-24-2014
In article <(E-Mail Removed)>, Eric Stevens
<(E-Mail Removed)> wrote:

> >> >what is needed is a colour managed workflow, with the image and each
> >> >device along the way having a profile.
> >>
> >> And how do you do that with a reference colour space, such as "XYZ,
> >> CIELAB, CIELUV"?

> >
> >users do not need to convert the image.
> >
> >what they need to do is use a colour managed workflow and the computer
> >takes care of the details.
> >
> >if you choose a different printer, pick the relevant profile and
> >whatever conversions are necessary are done automatically.
> >
> >once again, let the computer do the work.

>
> But the computer has to have some standards against which it can
> determine the meaning of the colour profile. Otherwise its a bit like
> saying to your tailor I want a 197 chest, a 132 waist and a leg of
> 106. At which point your tailor will say "Huh! Waddaya mean?".


the computer knows how to convert it. the authors of the profiling
software need to understand the math to write the software to do the
conversions. that's about the extent of it.

the end users do not need to understand any of it, other than how to
use profiles in a colour managed workflow.
 
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nospam
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      01-25-2014
In article <(E-Mail Removed)>, Eric Stevens
<(E-Mail Removed)> wrote:

> >> >what they need to do is use a colour managed workflow and the computer
> >> >takes care of the details.
> >> >
> >> >if you choose a different printer, pick the relevant profile and
> >> >whatever conversions are necessary are done automatically.
> >> >
> >> >once again, let the computer do the work.
> >>
> >> But the computer has to have some standards against which it can
> >> determine the meaning of the colour profile. Otherwise its a bit like
> >> saying to your tailor I want a 197 chest, a 132 waist and a leg of
> >> 106. At which point your tailor will say "Huh! Waddaya mean?".

> >
> >the computer knows how to convert it. the authors of the profiling
> >software need to understand the math to write the software to do the
> >conversions. that's about the extent of it.

>
> Here we go again. It's not about what the computer knows or the
> computer can do for the user.


of course it is.

> It's about the definition of colour
> spaces such as sRGB, and whatever else it is you have snipped, for
> which you need an underlying reference system such as "XYZ, CIELAB,
> CIELUV".


no it isn't.

the user wants as close a match as possible, given the limits of a
device. that requires a colour managed workflow.

they don't need to know the math as to how it works.

> >the end users do not need to understand any of it, other than how to
> >use profiles in a colour managed workflow.

>
> True, but you are changing the subject.


not at all.
 
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