JOBO Expert Drum Streaks

[Jurgen Estanislao]

Been developing 11x14 and 14x17 negatives in my expert drum for years now, as of late I have been noticing straight streaks on my negatives.

What could be the cause and solution?

 

[koraks]

It would help to see some examples.

 

[John Salim]

I'd say slow rotation speed and / or not enough chemicals !

John S

 

[Carnie Bob]

I have found with the expert drums I have to manually agitate invert and twist for the first 20 seconds of development, I have made this part of our routine for over 20 years .

 

[blee1996]

Assuming you are using CPP2 or similar. The nylon gears lost some grip? Also check the cog wheel and tighten its center screw. If worn, they might get slow or skip. You can still get replacement parts from Catlabs.

 

[Jurgen Estanislao]

Here's an example, I am using a 3062 drum on a Stark Rotary base. It's a single streak for the past three or four negatives I have encountered it on the same area.

As mentioned never experienced it before.

 

[RalphLambrecht]

Here's an example, I am using a 3062 drum on a Stark Rotary base. It's a single streak for the past three or four negatives I have encountered it on the same area.

As mentioned never experienced it before.

I can't see a streak.

 

[Jurgen Estanislao]

Here are inverted examples it's a horizontal streak

 

[Jurgen Estanislao]

Here's another one

 

[cowanw]

Perhaps you are taking too long between filling and rotation if you fill with the tank vertical. I fill my tank while rotating using a funnel and and a length of large tubing.

 

[mshchem]

Are you using enough active developer? I had this happen with diluted XTOL, used a greater volume of developer and problem went away

 

[MARTIE]

Those stipes are quite defined for chemical. Are you certain it's not mechanical?

 

[Vaughn]

I agree. It does not look like a chemical issue… Perhaps a light leak or perhaps, as suggested a mechanical issue.

 

[koraks]

Perhaps a light leak

The horizontal line shown in some of the sheets does remind me of that.

This one looks like at least in part a processing problem, with the edges of the sheet having been exposed to the fixer for only a small part of the time:

There's also signs of foaming in the partly processed areas.
@Jurgen Estanislao does that sheet show signs of incomplete fixing? What happens if you re-fix it?