I have just got six 4x5 Velvia sheets back from the lab that are very, very red. The whole sheet has a distinctly red tone evenly distributed across it. I've seen it before too in other sheets but not in this batch.

These six were shot in the same session using a Kodak Portrait and a Heliar lens.

Other 4x5 sheets from a recent holiday are more normal. So the processors may not be at fault.

Has anyone seen this before? Is it because these sheets were left out of the fridge after shooting? Was it the lenses?

Is it possible that older uncoated lenses let through a bunch more IR or something?

Is it because the processors happened to get these exact six sheets and processed them in a bath at the wrong temp??

Thoughts appreciated.