dudley_harris

I agree with the static electricity idea. I have three Mamiya M 6s

and all of them would produce black marks with 220 film on a cool dry

day. The camera actually creates these marks when the shutter is

fired. Mamiya replaced the film rollers correcting the problem by

putting rubber rings around the film rollers.

I had a problem with the 5 liter size earlier this year. Some batches

gave negs underdeveloped by about three f stops. Talked to Kodak.

They gave me new packs. But here is the answer to predicting if the

batch you are mixing is going to be "good" or not. When you mix

package A it should turn slightly yellow cloudy. If it makes a clear

solution, there will be a problem. Don't use it.

 

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I tried to get Kodak to verify my observation and prediction, but they

became unresponsive after simply replacing my developer.

I shoot with a Mamiya 6. With HP5 220 I get a gray vertical line in some negatives that corresponds to some defect with a roller. I do not get that line with Tri X 220. I have been corresponding with Japan Mamiya to try to figure out why the line occurs with Ilford films. So far, no one seems to be able to figure it out.