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 13:22:51 -0600
On Jun 2, 2013, at 12:54 PM, Ben Goren <email@hidden> wrote:
> And, again, it's a close match for how I remember the scene.
So that's another example of colorimetric accuracy based on memory?
> I can tell you from personal experience that I can place the original and a print side-by-side on my kitchen table (with overhead Solux track lights providing the illumination) and the artist herself has to very critically examine the two to spot the differences -- and those are almost always only in the areas where she used paints that lie significantly outside of the iPF8100's gamut.
I expect you can as can others without having to resort to whatever colorimetric accuracy is supposed to mean. Many users attempt and can match two differing media or this list and the tools we use wouldn’t exist.
> Mask off the sky and the rest of the scene is a good colorimetric match.
You say that but I'm trying to understand how anyone else can agree to that conclusion (still begging the question, what defines colorimetric match or accuracy).
> Didn't I address that in a previous post? I'm sure I did.
>
> Average DE is generally in the 1-2 range, with maximum in the 6-10 range with colors so saturated they lie outside of the gamuts of typical working spaces.
You provided values, but how you came to them, or how you gauage the accuracy of what you remember at the scene is still something I don't understand.
> Obviously, there are hard practical limits to what one can remember days or weeks after being in the field.
Indeed! Here's my 'beef' and question: you've stated the goal of this so called colorimetric match and accuracy but it appears to be based on a perceptual reaction and on what you think you recall seeing. If we were both at that scene and you said you remembered a color looking one way, I disagree, who's right and how do we decide scientifically? IF I measure some flower petal at the scene spectrally that's one set of useful data. IF I recall a color and say it does or doesn't match, who's to say that's correct, close of a mile off?
> I'm sure I could have taken my i1 Pro into the field with me and gotten spot measurements of everything in sight I could lay my hands on
Indeed, that's hard and a lot of work. But short of that, what proof do we have? Isn't the goal of colorimetry an non ambiguous set of color measurements that don't rely on a personal interpretation of what we see as color? Is this definition incorrect:
> Colorimetry is "the science and technology used to quantify and describe physically the human color perception
I'm asking for the science and technolgy used to quantify and describe physically the human color perception you're talking about in terms of what you recall at the scene and further if your description of colorimetric match is visual, numeric or both. Making a print that matches a Macbeth isn't difficult, Bruce illustrated this way back in 2004 using ACR. I've done similar tests. That then proves ACR is (or isn't) a product that can produce a so called colorimeric match?
On Jun 2, 2013, at 1:12 PM, edmund ronald <email@hidden> wrote:
> All these issues could be solved if Adobe added a repro mode to ACR.
What's a repro mode? Now we're adding another undefined term on top of "colorimetric accuracy" based on someone's memory of a scene, without any actual colorimetry at play?
Getting something to match is absolutely doable and one can use insturments and colorimetry to measure any number of colors to prove they numerically match. Putting an original and repro next to each other and seeing a close match is absolutely doable within reason, I'm not saying it can't be done. I'm suggesting there's a bias expressed about one raw processing engine that is said to be unable to produce either which isn't my experience nor that of others I know and respect. The terms used before and after matching and accuarcy don't appear to have a structure for proving these matches for anyone who's not there to view the two and further, we've been told what we recall and what we produced match which I don't buy for so many reasons. What you recall and what you ended up with isn't based on colorimetry as I understand it.
Andrew Rodney
http://www.digitaldog.net/
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