Inconsistent Development

[Don Wallace]

This a continuation of another thread. I hope some of you guys have some suggestions. This is driving me nuts.

I am having problems with inconsistent development in large areas of sky or blank wall. This happens mainly with my development of FP4 4x5 in my Jobo CPE2, but I have also had the problem with 120 in a Paterson tank. Let's stick to the Jobo for now. I have attached two tests I did just yesterday. I pointed the camera at as much blue sky as I could find.

Test 01 is FP4 in HC-110 dilution F, at the high speed (50 rpm)
- presoak 1 minute
- develop 8 minutes
- wash 1 minute (not stop bath)
- fix 2 minutes
- wash, HCA, wash

The above is my normal procedure. It was suggested that I used a 5 minute presoak and use the Ilford development times. Ilford says 9 minutes in HC-110 B rated at 125. I rate at 100, so I used 8 minutes for my second test.

Test 02 is FP 4 in HC-110 dilution B, at the high speed (50 rpm)
- presoak 5 minutes
- develop 8 minutes
- wash 1 minute (not stop bath)
- fix 2 minutes
- wash, HCA, wash

In both tests, you will see splotches in roughly the same spot in the sheet, as well as pinholes in the neg.

 

[JBrunner]

Looks like handling marks to me as well. In regards to the pinholes, the varied shape and density probably indicates dust on the film prior to exposure.

 

[Don Wallace]

DANG! It can't be that simple. There has to be a much more complex technical explanation. Clumsiness on my part? Well, I never...

To be honest, it doesn't look like fingermarks to me. I like to think I am pretty careful, but what would be the point of posting here if I didn't listen to the advice of others? I will redo the test tomorrow and wear some linen gloves while loading.

In the meantime, I have attached two more images, this time of the negative rather than positive version, just in case that makes any different to your assessment. I scanned the whole neg (in the previous versions too) so what you see is the full 4x5 image.

 

[McFortner]

DANG! It can't be that simple.

You're right, it's those space aliens. They love to ruin perfectly good photos....

Of course when it comes to my pictures, it's 'cuz I'm all thumbs!

Michael

 

[JBrunner]

Frikkin space aliens.

 

[EricEvanLee]

The pin holes could be from too strong a stop bath. Try diluting it more, and leaving it in the bath for less time.
Eric

 

[JBrunner]

The pin holes could be from too strong a stop bath. Try diluting it more, and leaving it in the bath for less time.
Eric

He's not using a stop.

 

[Don Wallace]

Well, I found the problem. Sunspots were increasing the activity of that particular dilution of HC-110, in combination with my Jobo not being in Feng Shui alignment the the orbital path of ...

Ok, I admit it. It was my grubby mitts.

I did another test today. No blue sky but very flat grey, pretty much the same reading as when the sky was clear. Usually, I give the holder a blast of canned air. This time, I wiped it and the dark slide with a damp cloth in case of any grease spots and then gave it a good going over with the vacuum. I loaded the holder while wearing linen gloves. I shot a blank piece of grey sky with a few treetops and the loaded the Jobo while wearing linen gloves. I used my normal development but without the pre-soak.

The sky is perfect. There are one of two tiny dust specs so I will have to be even more careful, but at least I know that the problem was just sloppiness and not something more arcane.

Thanks for the help, guys. Unless I missed something, it looks like this problem is now licked.