Others can see my detailed analysis, conclusively proving that the green channel was clipped in patch 1.
And that in what way answers the questions asked of you about the methodology and matrix used to define accuracy? None. The clipping BTW IS seen in a specular highlight above the target itself from the metal bar holding the target. Again, so what?
I proposed with this example (which you continue to use to ignore the real debate here, your undefined methodology for the term accurate) to illustrate how WB can fail
. Nothing more. You made a very simplistic statement about WB which like Herman Cain, you are now backing away from. I think I proved your simplest statement doesn’t wash. You want to ignore that and go down a rabbit hole about clipping, how ACR versus LR do or do not let you click there etc. Point is, WB can be totally wrong. I told you that clicking on the 2nd patch is a better move long ago. Would you like me to expose less to the right such there is no clipping anywhere? Would that then get you on the topic, explaining the so called accuracy metric and methodology?
I doubt it.
I wish I hadn’t provided the “here’s an example of how WB fails and doesn’t produce accurate color
” part of all this, it was a great way for you to circumvent the basis of my original post about your poor use of language (WB produces accuracy
). You’ve been asked a number of times how one correlates this ‘fact’ based on the scene colorimetry. You haven’t nor do I believe you can. You ignored the time accuracy analogy. In that example, we have methods and values we can use to define
what is accurate
and by what degree. Instead you focus on clipping. Its obvious to me you just want to throw out terms of your making and can’t provide any evidence that any WB is colorimetrically accurate or that WB isn’t subjective.
Here’s what you need to do if you can. Explain what you mean by accurate
using a process we can follow to prove that a specific WB process produces accuracy to the scene, then some metric value to define what is and isn’t accurate.
If I measure two patches with a Spectrophotometer, I can tell you how close, (how accurate) the two values are using a specific dE formula. I can then suggest that a dE value of X produces an acceptable match and a value that doesn’t. We can easily agree that a dE 2000 value of less than one is a visual match. We can agree that a dE of 4+ isn’t. We can define a process (measure the two colors in X software, set it to use this dE formula). Anyone with the equipment and software can produce this set of tests. When we say “this patch matches that patch
” we are not pulling a statement out our ass. If we wish to define the accuracy of a profile we built, we can do a similar test with thousands of patches. We can calculate an average, max, min, Stan DV and make a non ambiguous statement about the accuracy of the profile. Or I can just say “this profile is accurate”, not provide any methodology and expect you to take my word for it. Without such a test process the statement is pure BS. I think your “WB=accuracy” is BS. Prove me wrong using some defined process like the example above (or the time accuracy example). You are entitled to your own opinions but not your own facts. Make your statement fact based! Can you? Still waiting. Or you can move on or be dismissive and talk about exposure and clipping.
If I come here and say, I looked at two similar patches and they appear inaccurate, that’s subjective and you or anyone else with the two patches, under the same conditions can agree or disagree. Only when we agree upon a method of measuring the two, specifying the conditions and the metric can we be non ambiguous. Your original statement has and continues to be total ambiguous and non fact based.
You stated many posts ago that WB produces an accurate
rendering. Prove it.
To do so you need to define how you came to this conclusion. You haven’t and I suspect can’t. There is a target we could agree upon, the Macbeth. Its under some undefined illuminant and in your “WB produces accurate color
” that can greatly change. WB under all illuminants produces this accuracy? Yes or no? You measured what at the scene to define this accuracy? You transformed the data from scene to output referred how to correlate this accuracy? You’re using dE or something else to describe the accuracy? Are you taking your accuracy based on solid colors or many colors in context? How many? ALL the colors in the target are accurate? If not all, what’s the average, max and min accuracy values?
Instead you simply say “this is accurate
” which seems to be pulling a bogus statement out of your butt. We’ve been over this a dozen times. You say its accurate, I say prove it and tell me by how much within the image. You are further convinced that this isn’t subjective so again, you’ll prove this is a measurable and not a appearance modeling issue how?
Its funny how you say I don’t answer questions (the pot calling the kettle black). You started this WB accuracy idea, can you prove it?