Presoaking film and development time

logan2z

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I recently started using rotary processing with a Jobo roller instead of inversion processing. When making the transition, I decreased development time by 15%. Now I'm thinking about presoaking my film prior to development. I've read that once the film is presoaked, it takes some time for the developer to displace the water in the emulsion.

For those of you who added a presoak step before development, did you increase development time in order to compensate for the time required for the developer to displace the water from the emulsion? If so, by how much?

Not sure how true this is, but I've read that Jobo started recommending presoaking in order to bring rotary development times back inline with the inversion development times recommended by film manufacturers. Given that, I'm wondering if I should just go back to the times I was using for inversion processing, but I'm curious to hear how much others have compensated for the presoak.
 
Rick A

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I started pre soaking film when I bought my Jobo many years ago, they recommended it to temper the drum and film to temperature. It also helps prevent air bells when used with standard small tank developing. I pre soak either way.
 
grat

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The developer is in solution (ie, water). If the emulsion is already soaked, then there's not really a osmosis boundary, and the developer should penetrate to the silver halide even faster. When I pre-soak, I don't change the development times.
 
Sirius Glass

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Presoaking [prewetting] does not change change development times.
 

pentaxuser

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Interesting comments in #3 and 4. Does that mean that IlfordPhoto is giving the wrong advice when it recommends that that dev times be reduced by 10-15%?

Rick A, can you tells us why it reduces airbells? If this is backed by science then this may be important to the OP of another thread where no matter how much he raps the tank he cannot get rid of what he is conviced are airbells

Thanks

pentaxuser
 
GregY

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I use Pyrocat HD in glycol almost exclusively. I always pre-soak with all formats (roll & sheet). As far as i know, the 10-15% time difference is because the film /developer is in constant motion on a roller base and would build more density....
 
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logan2z

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GregY said:
As far as i know, the 10-15% time difference is because the film /developer is in constant motion on a roller base and would build more density....
Click to expand...

That's my understanding, which is why I reduced my development time by 15% when moving to rotary processing. But I wasn't presoaking so was just curious if I should increase it a bit (from the already reduced time) due to the presoak. Based on the comments so far, I think I'll just keep the time as-is and not adjust for the presoak step.
 
GregY

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Like "grat" i've always thought pre-soaking made the developer work better....more uniformly. I'd like to hear a scientist's take on "displacing the water"..... i can't make sense of that.
 

Paul Howell

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I use a Unicolor film drum with up to 8 rolls of 35mm, I follow the old Unicolor directions and reduce development time by 20%, no mention of a pre soak. If I was using C 41 or E 6 at a 100 degrees F, I would likely do a presoak to temper the drum and reels and bring up to 100 degrees F before developer.
 

AgX

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Rick A said:
I started pre soaking film when I bought my Jobo many years ago, they recommended it to temper the drum and film to temperature.
Click to expand...

-) I do not know where Jobo said so. Instead they advised tempering by rotating the loaded tank in the tempering bath

-) in their E-6 manual Jobo explicitely advised NOT to use presoaking
Jobo USA explicetely advised NOT to use presoaking for ANY colour process

-) in their b&w manual they explicetely advised pre-soaking, but for more homogeneous development
 

Paul Howell

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AgX said:
-) in their E-6 manual Jobo explicitely advised NOT to use presoaking
Jobo USA explicetely advised NOT to use presoaking for ANY colour process

-) in their b&w manual they explicetely advised pre-soaking, but for more homogeneous development
Click to expand...

I guess I would have done all wrong. Will keep in mind if I ever do color in my Unicolor drum.
 

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Pre-soaking is one of those topics where for any approach a strong base can be found...
 

mshchem

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For black and white I mostly use XTOL straight, no dilution. I use the suggested times Eastman Kodak came up with over 20 years ago, FOR rotary processing. With other developers I use recommended times, no reduction. No real reason to prewet, I have done so in the past to get up to temperature.

Recently I've seen Jobo recommend prewet.

The short 3'15" development time for C41 requires temperature is spot on, prewet helps warm up cold tanks.

The only way to know for sure is to do your own testing. For me I tend to not reduce development time with black and white negative film.

E6 is where you have zero room for error in 1st developer.
 

Rick A

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Air bells are not an issue with rotary but do happen with small tanks, which is why you need to bang the tank on the counter. with pre soak the film emulsion is fully hydrated and there's no surface tension for air bubbled to stick to. I should have also added that I don't change developing times for pre soak, but do for rotary processing.
 

pentaxuser

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Thanks, pre-soaking as a cure for airbell formation appears to be the view of others as well. Presumably the initial agitation cycle immediately after pouring the developer onto a dry non hydrated film is what allows the airbells to stick but how bad this is would seem to depend on how much air is in the water as a result of how high a pressure water is delivered from the tap and how quickly it then gets used.

Certainly this makes sense to my intuitive logic be that good or faulty . However what still troubles me is why for some users the sharp raps do not completely work and why even if on the first agitation cycle some surface tension is still there to the extent that a bubble or two remain, that surface tension is not relieved enough to prevent a second set of raps at the next cycle to remove all airbells?

Then there is the "Ilford Elephant"in the room which is that it says that a pre-soak does not harm but confers no benefits either to development. OK you might argue that Ilford's statement about pre-soaking being unnecessary addresses the effect on film development only and does not cover the problem of airbells but if these are a problem for non pre-soaked film then as airbells do cause problems you'd imagine Ilford, at the very least, to say that in extreme cases pre-soaking might be necessary.

None of the above questions matter a jot, of course, if you have an airbell problem that will not go away. In that case you will try anything and everything to rid yourself of it.

pentaxuser
 
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logan2z

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For those of you who prewet/presoak before rotary processing, do you do it via rotation or some other technique eg. static soaking with occasional inversion? I figured I would rotate the tank for 2-3 minutes before beginning development using the same amount of water as developer I use and at the same temperature as the developer.
 

Sal Santamaura

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Time to do a thorough search of the PHOTRIO archive. It's replete with threads on this subject. You'll find that presoaking/prerinsing/prewashing (take your pick of terminology) in rotary black and white processing neither has any deleterious effect on development nor can be said to definitively result in an increase or decrease in required development time. That varies with each individual film/developer combination; some need more, some less. Only testing of one's own materials will provide a useful answer.
 

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Has anyone here experienced an air bell problem that would not go away? None of our 125 students per quarter for the decades I was associated with the photo program at the university ever did.
 

Sirius Glass

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That is the reduction time of the small tank development again not related to prewetting. I use the film or manufacturer published time for rotary processing which since it has been lab tested is more accurate.
 

MattKing

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Via rotation, in my case.
 

Sirius Glass

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I too presoak for 2 to 3 minutes with the drum or tank rotating dump the water and start pouring in the developer.
 

Paul Howell

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Vaughn said:
Has anyone here experienced an air bell problem that would not go away? None of our 125 students per quarter for the decades I was associated with the photo program at the university ever did.
Click to expand...

I never had an issue with air bells, not with Kodacraft apron tanks, SS tanks, Yankee, Patterson, or other plastic reels, or with Unicolor reels and film tanks, 35mm MF or 4X5. Last film I presoaked was Bergger based on Bergger's data sheet.
 
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