Ray's suggestion was
retain the potential for highlight and shadow detail recovery through floating point arithmetic
The gamma curve is the last one; there is "S" curve, specific contrast enhancement, highlight- and shadow recovery, black point, white point. In order to be able to do that, the entire spectrum of the demosaiced linear data must be retained.
I don't know how to explain it any more clearly than I have. There is no problem making contrast (or hightlight or shadow recovery or black point or...) adjustments in linear space. One's editing program simply views the results after gamma adjustment, in real time.
The next step would be not to perform the color space conversion but to leave the data in the camera's color space, and let the presentation do the conversion depending on the medium. This is logical, isn't it? (The gamma curve depends on the color space, but if that is not fixed, then the color space too can be changed). Your image shot in raw could be presented much better on a monitor with ProPhoto capability; I am sure such monitors will come. This would allow even for the color adjustment (like it is being done by Picture Style or Camera Profile). Adjusting saturation and brightness directly at the presentation is only natural.
I can think of only two reasons to avoid a color space conversion: i) destination color space is insufficient for the required purposes ii) destination bit format would cause an unacceptable loss in fidelity (precision). We believe that a floating point representation with the same primaries as sRGB addresses both issues. If a users disagrees, the traditional pixel formats in which you can leave the data unmolested remain available.
"Only natural"? I don't really know what to make of 'only natural', but let me say that in practice
, the techniques I've described work just fine. If you've viewed or edited a JPEG image file in Vista or Windows 7 you've already been using the techniques I've described. This technique has been shipping in Windows for the past 2 1/2 years, worldwide. I know, because I led the team that replaced the Windows XP imaging pipeline--we spent four years developing the hardware-accelerated floating point imaging pipeline and made sure it would work with JPEG-XR, and even with legacy file formats (ie. JPEG, TIFF). So it is hard to say that these ideas don't work, because the world is already using them!
There are two problems with this:
1. When working on an image for example in PS, previous steps must be "fixed" in order to make certain adjustments. You can't make for example enhancements by curves or on selected colors without knowing the result of the previous steps.
2. I am pretty sure, that most photographers would not publish their worthy images in this quasy raw format, which is fully open for further adjustment.
1) Yes, when re-editing and baking those changes into the bits you will accumulate error based on the precision of the pixel format. Of course! This is true for any non-parametric edit in any format--this is no exception--except that those concerned can use pixel formats with very high precision (low error). Further note that JPEG-XR does not prevent anyone from using parametric edits, should they wish to, but then portability issues become the primary concern. There is no free lunch!
2) This argument sounds like you are saying that photographers won't like it because the format is too good
! To paraphrase my understanding of this point: "Having one's digital files available in all their fidelity for others to edit might be too scary for people." Perhaps, but I don't think most photographers are relying on the limitations of a pixel format to protect their intellectual property--typically, they publish a low-resolution preview. Indeed, by the amount of FUD
being spread in this thread, it is hard to imagine that the technology is well-enough understood by the general population for "security by pixel format" to be the case.
Bottom line is this: People needed to know and understand too much to edit their images without damaging them.
We did our best to develop an improved tool for photographers which could work very well at helping people have i) better quality images and ii) a simpler workflow without any additional effort, knowledge or special training on their part.
No one is claiming the technology saves babies (though there may be applications in the medical field...), solves world hunger or is perfect in any other way. Simply that special, third party tools should no longer be NECESSARY
to get the most out of your files.
At the risk of repeating myself (again): you still want 3rd party tools? Mosaic'ed data? Parametric edits? 16-bit integer? Clipping? 8-bit integer for security reasons? No problem--to the best of my knowledge JPEG-XR has not taken away any of your choices, but rather offered additional, and we feel, more effective ones.
The JPEG committee met in Lausanne
back in 2007 and seemed to agree--they began the process which has since made this technology an international standard. That seems to be a pretty good endorsement in my book.
Gabor, I do respect your knowledge and expertise in the integer raw domain. I have seen you take countless hours to help others understand with graphs, charts, screenshots, in numerous posts to help clarify misunderstandings and put solid information out there (although, at times, I personally wish the presentation was more civil). But in this thread, there has been too far much supposition and speculation masquerading as fact.
I feel the information is now out there, and you and others may choose to accept it or not, but that is, of course your/their choice. For me, though, the theme in this thread that "it won't work" has run its course.