It is like you neglect the difference between accuracy and precision, and the fact that they are only loosely tied to each other. What you require is not only accuracy, but accuracy AND precision on the spectrometer level.
Sounds like those new car commercials (I prefer Sweet and Sour Chicken to just Sour Chicken). So yes, I desire accuracy and precision. The post is about the accuracy of color in non standard light. I didn't write this, I have commented on the issue of using accuracy in the question.
And I think you exaggerate the degree of imprecision introduced by subjectivity. As I wrote above, I think that "everybody who has ever seen this kind of light/scene will at once be able to identify it as being more realistic than e.g. the one obtained by the AWB."[What I meant was the example in post #23, and it turns out it was not obtained with AWB, but with a grey card].
That may be true. It doesn't change the issue of the language the OP is using and the need to express some metric of accuracy which as yet hasn't and probably cannot be stated.
>hours or days later when we process the image to match 'what we recall'?
You are re-introducing the time-memory factor which is overcome in grade 2.
Over come how and if so, by how much?
1-My point is that we are very probably BOTH more accurate than to other persons, who just use a free hand estimate, and even more more accurate than another two persons, who do not do it on location, but are referred to their memory.
Probably but how to prove and by what degree? You know the old saying about opinions.
2-When we both measure the length of say a football field with a tape measure, the results will differ. Does it mean the term accurate can not be used for the method?
It's more accurate than guessing. It's more accurate than using your right foot. We can pull out all kinds of devices, one more accurate than the next to attempt to dismiss the previous measurement. In terms of color accuracy, we at least have a metric of which anything finer is invisible
to us. If we measure a color and we are told one instrument says the differences between it and another is a dE of 0.5, another is a difference of 0.05, it's moot. We can't see the difference in either case. It's interesting to know one reference grade device is far more accurate than the other, but if we can't see the lesser accurate difference, who cares?
If your goal is to come up with the length of a football field because you have to build one, does it matter if one measurement is different from the other by 0.05 inches? Or even half a foot? Whoever is paying for the field probably has some metric of error or accuracy they desire. At some point, it doesn't matter. Is +/- 1mm important? With the subjectivity issues I raise, we have no metric to even agree upon as being a useful goal.
I think no. I think it only shows that EVERY measurement has an error, little or large. Our to measurements will differ by decimeters, maybe even meters - but they are very probably BOTH more accurate than a freehand estimate of the length.
But you did measure the item with differing methods to at least come up with a value and one can produce a value of which we agree is acceptable! We do not have this in this discussion because nothing was measured and everything is subjective. If we use your argument above, we have no use for measuring anything because someone can use a higher grade device to disprove the first measurement. If not disprove, suggest it's not accurate. And this is useful to a degree because until we measure and have a metric of what is acceptable, who says the football field has to be within +/- half a foot or 1mm?
That said, I don't really need the word 'accurate' to be happy.
And I said good for you. But there are others here too, and the OP who asked the question using that specific term: accuracy.
But at least I'll know approximately 'where I am'.
How do you express that to others? There's no metric. There's no way to agree with the premise which might be the goal <g>. Again, the question was, is accurate color possible in non-standard light. I submit the question should be reworded. Or we need some means to come up with an accuracy metric. I don't know how you do that without measuring.