Hi Bradley,
It seems that those tags were inserted by ImageJ. There were other issues with that 3D image file (by-slice scaling was used converting from 16-bit to 8-bit), and I have now reconstructed it from the 2D slices using ITK code.
Not strictly relevant, but I am disappointed to find that the new 64-bit version of Irfanview still can’t handle files bigger than 2 GB - at least, not a big file that I create.
Gib