Monday, September 21, 2015

Mind the Gap!

Mottled negatives are a sign of a tight gap.

Some negatives produced with New55 PN can be seen to have a mottled look. This mottling is usually caused by too tight a gap in the 545 holder. The reason for this tight gap can be stiffening caused by age, or old, dried reagent in any of the rollers, or in the journals the rollers roll in.  Too wide a gap and the positive image will be blurry. The balance is achievable and over time we will get this more under control.  In the meantime, and going forward the 545 holder needs to be cleaned thoroughly.
Mottling. The gap is tight.

I have found a few decades-old 545s with very tight rollers. Make sure your rollers are free.  If you suspect that you have a tight gap, you can compensate for it by running a layer of thin masking tape down each side of the sleeve.  In the foreground is a taped sleeve to illustrate the point. You can see that an added edge of black masking tape has been added. It can be any color, of course.  You might do this if you suspect a too-tight 545 until we find a way to compensate for the variation of these somewhat elderly 545 holders.

The top sleeve has edge tape to increase the gap