I've taken a few photos with a new B+W ND 6-stop filter and found that it leaves them quite warm. I'm able to correct this in ACR using temperature/tint sliders. For the few photos I've taken so far, the same temp/tint settings seem to work for each one.
I've heard that color cast from a given ND filter can vary between cameras and lenses. But presuming I continue to use this filter with the same camera and lens, is it safe to assume my WB correction will be the same every time, for any photo? Or will it be dependent on other conditions like lighting and exposure/aperture?
Note that I ask, because if the color cast varies based on some conditions, then I will probably take no-filter companion shots for any filter shots that are important, so I'll have a reference point for matching WB later. Though, it would be nice to not have to always do this.
To clarify my question, here is a concrete example. Please excuse the horrible photo.
Here is a RAW file shot with no filter. I used auto-WB, and ACR says that "as shot" the temp is 5400 and the tint is +13.
And here is another RAW file, shot with my 6-stop ND filter. Same tripod, same composition, same lighting (different exposure settings though). Also used auto-WB. Resulting in temp of 5700 and tint of +43. It is noticeable warm. If I adjust temp to 4300 and tint to +10, I think it is a pretty close match to the first one.
So, I needed to drop the temp by 1400, and the tint by 33, to correct it. My question: can I make these exact same drops to every shot I ever take with this filter/lens combo, to make it match what would have been the result if I hadn't used the filter? Or will it vary?