Un-even dev, only by lack of agitation?

[RSalles]

Hello,

I have developed some 4x5 negatives the last week-end, and unfortunately three of them had some uneven developed areas at open ski.
Film: Shanghai GP3, Yankee agitank, HC-110 dil H (1+63).
As my workflow has always been nearby the same for the last years regarding agitation with 4x5 film, I would ask what else can contribute to this unevenness in the negatives, restricted to the open sky area only:

_MG_7743 - _MG_7748 by Renato Salles, no Flickr


_MG_7736 - _MG_7739 by Renato Salles, no Flickr

Cheers,

Renato

[Randy]

Any uneven development is not restricted to open sky only, it is just much more visible in the sky because there is no place for it to hide - no roads, rocks, trees, lakes, cows, etc. On my monitor I can not really make out unevenness on your samples, so I can't really offer a cause or prescribe a corrective measure, even though at present, I am the master of uneven development, especially with my 8X10 X-ray negs. I have been fighting with it for months now, trying different methods to correct.
The only thing I can suggest is to shoot a few test shots of scenes with mostly sky, or at least 1/2 the image being clear sky - try different agitation methods and frequencies to see what results in the smoothest sky's. For my 4X5 films, I have always processed in trays and have never gotten uneven development.

[tuco]

I see the density streaks just fine. Most likely you need to either increase your agitation or make the one you use more vigorous. Gently moving your sheets in a tray can yield laminar flow across the boundary layer on the sheet. The developer is working in this very thin layer against the film and gets exhausted quickly. So we agitate to replenish it. But if the fluid flow is laminar, it will "slide" over that thin boundary layer leaving the some of the exhausted developer in place.

[Ken Lee]

Another consideration: colder developer (or weaker developer) and longer development time. Use ice cubes if necessary to lower the temperature of the developer.

[Jim Noel]

When I was teaching at the college the most common reason for such streaks was overly gentle agitation. If developing in a tray, my favorite method, agitate by lifting 3 corners just to the point of sloshing the developer out of the tray.
If we think of the tray corners as 1,2 3 and 4, for the first agitation cycle lift corners 1, 2 and 3. For the second cycle corners 2,3 and 4, third cycle 3, 4, and 1, etc.
When I develop 4x5 film a cycle takes about 4 seconds. For 8x10 it takes 5-6 seconds and for 7x17 - 6-7 seconds.
Be sure to use a tray one size larger than the film.

[Jerry Bodine]

Another consideration: colder developer (or weaker developer) and longer development time...

When I was teaching at the college the most common reason for such streaks was overly gentle agitation...

FWIW, when I tested HP5+ / HC-110 for EI and contraction development down to N-5, I heeded AA's suggestion to ensure even development. I came up with EI=200, then for N-5 used 1+123 @ 20C, making two identically exposed negatives - one with 31-step wedge (in camera) and another w/o wedge to check for uniform density. Since total dev time would be quite long, I carefully placed the films in a 4-up hanger to keep them from floating in the 11x14 tray. After a 2-min water pre-soak (very controversial subject) with moderate agitation, I placed the hanger in the diluted dev (25ml concentrate + 3075 ml water) and agitated by slowly raising/lowering it while keeping it submerged (to prevent foaming and surge marks from dev squirting through hanger's edge holes). Total dev time = 20 minutes.

1st test: Agitate 1st minute, then 15 sec every 3 min gave even development.
2nd test: Agitate 1st minute, then 15 sec every 6 min gave uneven development.
3rd test: Agitate 1st minute, then 15 sec every 5 min gave even development.

Plotting the data showed that an additional stop of exposure was needed (beyond the EI 200 reading) to preserve shadow details for N-5 development. While this testing can be diagnosed as overly analytical, I found it to be an extremely educational process to go through at least once. It was a bit expensive too - I've only presented the final results here rather than every step of the way.

[Jim Noel]

The testing may have been "overly analytical", but you appear to have solved your problem.

[axs810]

Do you pre-soak before development? Maybe that would help

[LabRat]

Also, it might be an issue with the film stock... Shanghai often has quality issues...

Steve K

[RSalles]

Any uneven development is not restricted to open sky only, it is just much more visible in the sky because there is no place for it to hide - no roads, rocks, trees, lakes, cows, etc. On my monitor I can not really make out unevenness on your samples, so I can't really offer a cause or prescribe a corrective measure, even though at present, I am the master of uneven development, especially with my 8X10 X-ray negs. I have been fighting with it for months now, trying different methods to correct.
The only thing I can suggest is to shoot a few test shots of scenes with mostly sky, or at least 1/2 the image being clear sky - try different agitation methods and frequencies to see what results in the smoothest sky's. For my 4X5 films, I have always processed in trays and have never gotten uneven development.

Randy,

Saw that also, I sort of photoshoped a the sky area to try to "hyde" a bit the strikes but it didn't happen. I'll do some test shots to try to nail the problem - maybe lack of agitation, but I tough i had the same amount of it, let's see, thanks,

I see the density streaks just fine. Most likely you need to either increase your agitation or make the one you use more vigorous. Gently moving your sheets in a tray can yield laminar flow across the boundary layer on the sheet. The developer is working in this very thin layer against the film and gets exhausted quickly. So we agitate to replenish it. But if the fluid flow is laminar, it will "slide" over that thin boundary layer leaving the some of the exhausted developer in place.

Tuco, that's what I had in mind when looking at the negatives in the light table, maybe I had filled too much the tank and avoided to spill some developer, and agitated less then usual.

Another consideration: colder developer (or weaker developer) and longer development time. Use ice cubes if necessary to lower the temperature of the developer.

Ken, thanks, I used 15 minutes at 20ºC which is enough time IMHO, maybe I have to be a bit more aggressive in the agitation, I'll see,

Do you pre-soak before development? Maybe that would help

Yes axs810, pre-soaked for 2 min at 20ºC

Also, it might be an issue with the film stock... Shanghai often has quality issues...

Forgot to mention, 2 sheets of Shanghai and 1 sheet of Foma 100...

I'll give another try and see what happens, that's f* annoying, maybe it's time to test BTZS, dunno... For tray... fear to be 20 minutes in the dark and dye bored, maybe not,

But thanks guys, your help have been very much appreciated,

Cheers,

Renato