I've been using a set of homemade BTZS tubes made from ABS pipe. They work fine, except every now and then a 4x45 negative exhibits slightly higher density in the *center*. Edge density is fine.(posted 8422 days ago)Anyone have any idea how this can happen?
Let me stress that the density is in the center of the negative, and is not a 'streak' running width-wise across the negative. If you look at a negative, you'll a circular section (about 2" in diameter) of slightly higher density in the center of the negative.
A friend who has a Jobo couldn't explain it either.
Ideas?
BTW: HP5+ 4x5 sheets, Ilfotec HC 1+31, 7:30.