Re: RPP raw photo processor 64
Re: RPP raw photo processor 64
- Subject: Re: RPP raw photo processor 64
- From: Andrew Rodney <email@hidden>
- Date: Sun, 02 Jun 2013 10:29:24 -0600
On Jun 2, 2013, at 9:30 AM, Ben Goren <email@hidden> wrote:
> Rather, the point I'm trying to make is that digital, unlike film, is very well suited for (reasonable degrees of) colorimetric accuracy
What we need is a strong and well presented case this is possible in all cases where one points a camrea at some scene. In fact, I'd like to see a definition of what 'colorimatric accuracy' really is and looks like and what metric is used to say it's been achieved. I'd assume you mean one measures the spectral data at the scene (how many?) and the camera and processing spit out the exact color numbers in a rendered image right? And that appears how to the end user (it shows a visual match on a display or output? It looks as we expect? It's pleasing, meaning it doesn't look scene referred and rather ugly?).
What constitutes 'reasonable'?
> but that Adobe has chosen to create a raw development engine that isn't even theoretically capable of colorimetric accuracy.
So once the above is defined, again there are methods anyone can follow that provides proof that an Adobe raw processing engine cannot in any case, provide "colorimetric accuracy"? Because dating back to the work of Bruce Fraser, he was able to use the Adobe engine to render a Macbeth that provided RGB values that matched what they are said to be in Lab in ProPhoto RGB of all 24 patches. Is that colorimetric accuracy and if not, why? This work Bruce did predates DNG profiles by years!
> Actually, it's been my experience that virtually all the complaints I see from photographers are results of colorimetric failures.
I would suggest most photographers don't even know what colorimetric accuracy or colorimetric failure is. They do easily understand non pleasing color.
> Improper white balance and exposure are colorimetric failures
Well it certainly isn't a recommend photographic workflow to improperly white balance and improperly expose! If I white balance a scene of a model on the beach at sunset, is that colorimetric failures? It would certainly produce an image that doesn't look anything like the original scene.
> That same enhanced contrast, in turn, is also responsible for many of the unnatural-looking skin tones.
So we're back to pleasing color? Or in all cases, what some are calling colorimetric accuracy always produces natural looking skin tones?
> I honestly think pretty much every photographer would benefit from a workflow that is initially colorimetric, and then gives the photographer full control over when and where and how to deviate from a colorimetric rendering.
If the vast majority of photographers treat their images as they did with film, then I'd disagree. Many forums have posts from photogrpahers that ask why their 3rd party converters produce a different result after building a preview than the initial one baked into the raw using the JPEG convesrion methods of the camera. They think and often desire that the initial raw rendering look like what the camera produced which we all know isn't colorimetric accuracy but it seems to produce an image many photographers desire, at least as a starting point. The entire point of raw is to avoid painting yourself into a rendering corner which is what you end up with the camera generated JPEG. Nikon's and Canon's rendering are not the same any more than Velvia and Agfachrome produce a match of the same scene? Which is correct? Initially, the one the image creator prefers.
> As it is, there's a great deal of ``secret sauce'' built into the overwhelming majority of raw developers, and not only is there no way to turn off said secret sauce, it's not even readily apparent that it's being applied in the first place.
And there was a lot of secret sause in film, the processing of the film and the filter packs needed to produce a desired result. Nothing new here in terms of image capture.
> I'll also note that many of the complaints I've heard about colorimetric workflows stem from people who've never actually successfully implemented one.
Or those that have and do not do copy work or scientific capture and wish to impart their artistry into the process.
> Often, they'll start with an Adobe raw development and then build an ICC profile from a badly-exposed snapshot of a classic 24-patch ColorChecker held by the photographer at arm's length...and then wonder why the results are so ugly.
Well that's not possible (Adobe raw engines don't support camera ICC profiles). Badly exposed images are to be avoided. Just look at the confusion over what is called ETTR (which I'd submit should be called ER or expose right, expose for raw data to produce ideal data if possible).
On Jun 2, 2013, at 10:11 AM, Iliah Borg <email@hidden> wrote:
> Given the exposure is consistent (current digital photographers do not recognize it and preach ETTR, even at higher than base ISO; and the vast majority believe that ISO is a change in sensor sensitivity)
Depends on the system too. A Canon system is quite different from a Nikon system in this case, upping ISO on the Canon can result in ETTR, and less noise**. Then there are what some are calling ISO-Less systems which work in a different fashion. ** http://digitaldog.net/files/100vs800iso.jpg
The issues being discussed here are complex and lumping all capture devices and techniques could be problematic. I'd submit that most photographers that choose to capture raw don't care at all about colorimetric accuracy and if they did, achieving it needs to be specifically addressed: which camera system, what kind of setup (controlled studio, not controlled), what converter and most importantly, the goal of the photographer. All the vaious sliders and controls in a raw converter are there because many of us want to produce an image based as we recall it or how we wish to preset the image to the viewer. I don't see anything but a tiny minority of photographers and color geeks asking for or complaining about the need for colorimetric accuracy, I do see them asking for tools that allow them to express their vision of an image. HDR, conversion processes for B&W, cross processing, issues with multiple illuminates, and the like seem to get far more attention from photographers.
Andrew Rodney
http://www.digitaldog.net/
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