I was printing today and had to open a more recent box of Ilford Glossy Warmtone to make two duplicates. The new box was probably about a year newer than the box from which I had been printing, and I was surprised at the difference in contrast levels between the two boxes. I print using a Beseler 45s color head, and I had to add about 20 units of magenta to compensate for the loss of contrast in the new box.

Have others experienced this? They're different lot numbers involved, so I wouldn't expect them to be exactly the same. But, I also wouldn't expect them to be that different.

I keep print descriptions for photos. But keeping track of contrast grade won't help with that kind of variability.