I have to stand corrected - Pete is right - the orange masking layer is a dye-coupled layer that will not develop a color in B&W chemistry. I'm at work now so I can't look at the negatives to see if there's a color cast or not. If there is, I'll post an addendum.(posted 8527 days ago)I suggested that the negatives may not be permanent because of the additional layers and unknown effects from the B&W chemistry. The silver image should be stable though.
Cheers,