Re: Media Testing for maclife.de
Re: Media Testing for maclife.de
- Subject: Re: Media Testing for maclife.de
- From: "edmund ronald" <email@hidden>
- Date: Fri, 5 Sep 2008 12:47:45 +0200
This a conflation between things that are true and things that are not.
As can be seen from the Capture One and the Raw Developer software,
both of which are considered by may professional photographers as very
high quality, profiles can be employed in a meaningful way in the
image rendering pipeline. With the advantage that the existing body of
knowledge and tools is then immediately available.
However, profiles -as they stand today- are not able to do everything
that is necessary. That is why technology standards undergo revisions.
One fact that everyone -except apparently Adobe- agrees on is that
there are both esthetic and exact aspects to Raw rendering.
Hence we can see that a baseline colorimetry for an image needs to be
established by exact means, dependent on the camera model and
illumination at capture. But then the esthetic aspects come into play,
where the photographer adjusts sliders or curves to achieve a "look".
This "look" should ideally be camera independent. Indeed a
photographer shooting with several cameras would wish the exact
decoding of the image to be coherent enough from camera model to model
that the same "look" can then be overlaid seamlessly on all the
images.
>From the above discussion we can see that several adjustments get made
in succession, say first a matrix that depends on illumination to do
the raw2xyz transform, then an abstract profile to adjust image
exposure -rendering to output-referred - then a "look" profile
applied in output space.
To answer Adobe's confused refutation of profile technology, the Raw
converter is a place where existing profile technology can be applied
several times, and an extension to the profile standards to deal with
the high dynamic range of the input-referred imagery at the source of
the rendering pipeline seems more helpful than an outright abandonment
of working technology.
The above analysis is of course technical. In commercial terms, an
open specification of the rendering pipeline would make Raw rendering
interoperable and create an open market for third party Raw plugins
(noise reduction, sharpening, aberration correction, look creation)
while the strategies suggested by Adobe ensure consistency at the
price of a total lock-in by the dominant company.
Edmund
On Fri, Sep 5, 2008 at 11:08 AM, Bob Frost <email@hidden> wrote:
>> Well, it seems that nobody wants to take into account the simple question
>> - why Adobe (being pretty much colour-savvy in all their applications) are
>> not implementing ICC-compliant custom LUT-based colour profiles in their
>> converters.
>
> As I reported earlier, Adobe says:-
>
> "First, ICC camera profiles used by raw converters today are designed to
> process output-referred (i.e., rendered) image data, not scene-referred
> (i.e., raw) image data. Furthermore, the sequence and placement of color
> transformations described in an ICC camera profile can prevent other image
> processing stages (such as highlight recovery algorithms) from performing
> optimally. Third, there is no standard that describes the input color space
> of the ICC camera profile color transformation (it is often, but not always,
> a tone-mapped set of RGB camera coordinates). Consequently, ICC camera
> profiles are not portable: they can only be used with the raw converter for
> which they were explicitly created in the first place. Using an ICC camera
> profile designed for one raw converter with another raw converter nearly
> always produces incorrect (though sometimes entertaining) results."
>
> from their website FAQs on the new camera profiles.
>
> Bob Frost.
>
>
> ----- Original Message ----- From: "Iliah Borg" <email@hidden>
> To: "ColorSync Mailing" <email@hidden>
> Sent: Thursday, September 04, 2008 8:22 PM
> Subject: Re: Media Testing for maclife.de
>
>
>> Dear Group,
>>
>>
>> Another, not Adobe-related question, is - are ICC-compliant LUT-based
>> profiles are suitable for quality raw conversion at all. On this topic I
>> would love to hear the opinions of other folks involved in raw convertor
>> development if any are present in this list at all. ICC approach is pretty
>> easy, and I fully understand why users (especially on ColorSync-Users
>> mailing list) want it. But is it a swiss army knife to open all cans?
>>
>> --
>> Best regards,
>> Iliah Borg
>> email@hidden
>>
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