Thank you both for your replies.
Les, my teacher thought of my shutter also but I have never had a problem with any of my negatives other than that they have been thick to very thick. Wouldn’t a shutter problem reveal itself either consistently or randomly as ‘unexplained’ negatives? All 36 exposures on all the rolls of film in question are consistently at Zone 7 and ‘unexplained negs’ way off in the ether some place are very rare. I have in the past and still do take pictures with this wonderful camera under very trying conditions (bright or dark) and it has always come through or I see where “I” have messed up.
Thank you David. I have Beyond The Zone System but found it difficult to understand. The book I am following, Brian Lav’s, is logical and easy to follow but than I am really just an amateur at this so let me explain his process a little further.
The first thing he has you do is shoot a gray card—bright day, card in deep shadow—but adjusting your f-stops so that you should be getting a Zone 1—this procedure is to eliminate normal film fog. Then you are instructed to shoot one below that reading, one at +1 and one at +2 and then finish the roll.
You take a clear piece of film and set your enlarger at a good height and stop your lens down to some middle f-stop. You then do a contact test strip at three second intervals until you have ten or so of them—You always use the same paper for all tests of course. You then determine how many seconds it takes to reach maximum black. If the test strip says it is 15 seconds he has you retry at just that interval because five 3 second intervals may not be the same as one 15 second interval. This is the amount of time to get ‘through’ the film fog. This is your Standard Contact Time (SCT).
Now you take the film that you shot with a Zone 1 frame from above and contact print at SCT. If the frame shot at Zone 1 shows just decernable gray than your meter is correct. My Nikkormat was correct, my Mamiya first showed discernable gray at the +1 setting and he had a chart for adjusting your ASA setting in such situations.
At this point you are advised to do the test as described above for Zone 5 i.e. shooting for the Zone and using standard development times and then changing them until ‘shot at’ and ‘printed zones’ are the same.
As I said when I first saw that I needed to lessen my 35mm development time (down 10%) when I didn’t see a difference in the contact print (came out as a Zone 7) I re-did the test with a new roll of film arriving at the same results. What drives me crazy is that after I developed the first roll of 35mm at 10% less time and seeing that I needed to do the same with my 120 film I developed the latter using exactly the same temperatures and times and the negatives dropped right back down to Zone 5!
I am going to do all the tests again but I wanted any input from experienced people before I did so. School is in session Monday morning again and I’ll have another go. Any suggestions you can provide would be absolute gold to me. I'd like to know any problems you see with the process, I'll abandon it and try a new method if I have to.