Re: : gamma bewilderment: A history lesson
Re: : gamma bewilderment: A history lesson
- Subject: Re: : gamma bewilderment: A history lesson
- From: edmund ronald <email@hidden>
- Date: Thu, 31 Mar 2016 18:51:37 +0200
ICC: a sclerotic organisation obsessed by scanned imagery converted to
print and controlled viewing conditions in a world where images are mostly
viewed on random screens.
On Mar 31, 2016 15:00, "THOMAS A LIANZA" <email@hidden> wrote:
>
>
> Hi guys,
>
> I have been reading the various p*ssing contests on this list and being
> one of the older guys on this list who was actually there at the start of
> color management, and one of the strongest critics of the ICC in the
> beginning I thought that I would throw out some historical notes here.
> When I started Sequel Imaging in 1989, color management was just
> beginning. When I heard that Microsoft was planning to establish an RGB
> standard with Gamma 1.0, I got on an airplane and went for a meeting at
> Galactic Headquarters to point out just how embarrassing that decision
> would be to the company. I explained at the time there would probably two
> emerging color encoding schemes one with an assumed gamma of 1.8 and
> another with an assumed gamma of 2.2. As far as the Apple gamma 1.8
> distinction, it wasn’t as stupid as many have assumed it to be. During the
> early period of Apple’s formation, Apple developed a lot of print and
> capture hardware that seamlessly worked with their platforms. All of this
> equipment was used at high background luminance’s and the evaluation of
> print to screen was made at insanely high view conditions. From a
> perceptual viewpoint, not a whole lot of research had been done at time,
> but Hunt and Stevens’ work was pretty well understood. Visual comparisons
> between monitor and print looked pretty good, although the color laser
> printer would alter a lot of that work, but the gamma 1.8 assumption worked
> pretty good for a long time. When Apple started making color output
> hardware, it was clear that there would have to be someway to calibrate the
> various color devices. That caused the development of ColorSync 1.0,
> which I can say, as an early adopter, worked well for the color
> reproduction products of the time viewed in uncontrolled environments at
> high luminance. Push forward to 1993 and we see the formation of the ICC
> with 8 founding members, all very large companies. HP and Microsoft were
> included in the mix, but I think they saw that the complexity that was
> being proposed would never work in the mainstream and we have, in 1996, the
> release of the sRGB specification. It is really important to understand
> that the sRGB specification is essentially an encoding specification with
> some peripheral documentation about the assumed viewing conditions. The
> sRGB spec fundamentally made color interoperable between different
> manufacturers and it was widely adopted very soon after introduction. In
> 1996, two very distinct paths of image reproduction emerged: one for
> consumer use(sRGB) and one for commercial use(ICC v2/v4). Between 1994 and
> 2001, the ICC released no fewer than 5 revisions to the specification,
> while the sRGB spec remained virtually unchanged, except for language
> changes as it moved towards ISO. As a small business owner, I was appalled
> at changes and the need to revise the software. Version 4.0 of the spec
> would finally be released as an ISO specification in 2010 roughly 17 years
> later. When I became Chairman of the ICC, I suggested that we move Version
> 4.0 into ISO (to minimize revisions) and move on to an advanced platform
> that could accommodate very high end activities using a full spectral
> workflow. This was not backward compatible with V4/V2, but it would
> accommodate a V4 profile in the CMM. I also directed that we provide an
> Open Source Reference CMM implementation to eliminate the interoperability
> issues of the V4 CMM’s . The latest work at the ICC has very little to do
> with the issues that this group focusses(obsesses) over. Now one final
> point about gamma and sRGB. If you take the time to actually measure the
> transfer function of a modern digital camera in sRGB mode, you will find
> that the working gamma is about 1.1-1.4 X higher than the sRGB encoding
> gamma. This is because the average viewer is taking the image in a high
> luminance environment and viewing in a low luminance environment. The
> print vendors tend to back this out in the print driver when working in
> sRGB mode. That is why a consumer level sRGB workflow actually works. In
> an ICC environment, a couple of things need to happen in the profile. If
> you take a typical sRGB camera image and print it through a simple sRGB
> profile and then out to the printer, it will look dark and contrasty. This
> has led the ICC to build a number of appearance profiles for sRGB, but I am
> not aware of where that work stands. The point is this: within the sRGB
> world, working gamma is not necessarily equal to the encoding gamma and the
> working gamma at different points in the process is not constant. The
> complexity of the ICC specification along with the multitude of revisions
> have lead to interoperability issues.
>
> Regards,
> Tom Lianza
>
>
> _______________________________________________
> Do not post admin requests to the list. They will be ignored.
> Colorsync-users mailing list (email@hidden)
> Help/Unsubscribe/Update your Subscription:
>
>
> This email sent to email@hidden
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden