Thanks, now the filter shows up in the list and everything works fine
@jdc : i made some tests with the hue variance method, and they seem to confirm our doubts with pictures that have a very un-balanced illumination.
This one came out pretty good:
ā¦ and also this one (just needs some contrast):
ā¦ but this one looks a bit off:
In reality, this scene was lit by a very strong red light from the right, and an orange/gold light from the front, so everything had a much stronger red tint.
This is the problem i think: how can an auto-wb method (however good it may be) figure out all this stuff, without any hint about the original scene?
So, this is what i do instead. First, i take a reference picture, pick the 2 neutral grey spots to calculate negative exponents, and manually set white balance via spot-wb:
Then, i blindly paste the same film negative and white balance parameters on all the other pictures from the film roll, and get this (note the exact same WB numbers on the right):
ā¦ which looks pretty accurate. You can get a hint in the upper left corner:
itās an āemergency exitā lamp (with huge amounts of coma from my lens at f1.4 ), one of those green/white signs, i think theyāre quite standard across europe at least.
To me it looks reasonably good, despite the rest of the image having very un-natural colors.
I know this is a super-dumb method, thereās nothing automatic, you have to manually setup the reference picture (it must not be a macbeth chart, any picture with 2 neutral gray spots will do), but afterwards you can set-and-forget all the other pictures in the film roll and get reasonable resultsā¦