Neutral Density Color Balancing
Hi Ben, neutral density filters are a useful photography tool, however they all cause a color cast to a varying degree.
I was thinking of using curves in Photoshop to correct this rather than trying to find a suitable gray sample point in Lightroom. Could you take a sample photo with and without the ND filter then create a curve preset to correct the color cast so with ND filter photo is same color as without ND filter photo? I assume one curve preset per camera would be required, maybe one per camera/lens as well. Once you have a set of curve presets it would quick to apply a color correction i Photoshop.