Just developed 6 sheets 5x4 in 510-Pyro, using the Massive Development Chart for guidance. The recommendation was for 22 minutes at 20C in Jobo CPP2. Stop bath was two water rinses, fixed in Fomafix for 3.30 minutes.

The film was exposed with a yellow K2 filter, as I wasn't chasing a Wood effect, just good contrast in the sky. Metered with the Reveni Spotmeter. All sheets came out completely clear, as if I had developed/fixed unexposed film. I can imagine where I might have inadvertently left a dark slide in for one, maybe two sheets of film, but not six.

Has anyone struck this issue before, or has some idea as what might have occurred?

Thanks, Peter.