Rotary(Jobo) Development Times vs Stand Dev?

[DanielStone]

hey all,

i was hoping that any of you could help me out. I know i could try this out myself, but due to being a student on a student's budget, I'm trying to conserve finances right now.

My problem is this: I'm finally getting used to(around 60-80% successful) with the basic zone system with TMY-2 in D76 1:1.

Up until now i have been using large tanks using stand development, but I have considered moving over to using a Jobo system at my local community photo center, primarily because of the smaller amount of chemicals to be used in the processing.

What is the average time to take off when using a rotary system vs. stand development? I thought it was around 10-15%, but wanted to check with you guys(and gals, the few of you on here) first before I have to do my film testing all over again.


Thanks

Dan

 

[bdial]

Kodak's data guide for D-76 has times for rotary processing; http://www.kodak.com/global/en/prof...stry/bwFilmProcessing/d76.jhtml?pq-path=14029

 

[Bruce Watson]

What is the average time to take off when using a rotary system vs. stand development?

There's too many variables to be able to give you more than a guess. Instead of guessing, why not use Kodak's suggested development times published in the D76 and/or TMY-2 tech pubs? That's a much better place to start.

 

[Venchka]

There is no substitute for personal testing.

My testing led me to 9 minutes in a Jobo tank turning 30 rpm on a Uniroller base. Film is HP5+ at E.I. 250. YMMV.

If you wish to use even less chemicals, Xtol 1:3 for 10 minutes. Same tank and motor base as above. So far that combination has worked for PanF+ (50), HP5+ (250) and Foma 200 (100). YMMV.

 

[Neal]

Dear Dan,

I find the data in the Xtol data sheet for rotary processing to be quite accurate.

Neal Wydra

 

[pentaxuser]

No experience of Kodak chems but Ilford recommends a reduction of 15-20% for rotary processing in comparison with its normal 4/5 inversions for each 10 secs in every minute of development. However this would only seem to apply if you do not pre-wet films prior to rotary processing. If you do and a guy called John Tinsley who wrote a book about rotary processing in the 1990s did pre-wet and he found that the same times as were applicable for hand inversion were correct for a Jobo rotary processor.

It's trial and error but a 15% reduction should get you printable negs and you can adjust from that percentage on subsequent development.

Rotary processing does save about 40% of chemicals ( 140mls v 240 mls) in a 35mm Jobo tank and works for most developers but not all. Some developers are not suited to rotary processing or at least do not produce their best results that way.

pentaxuser

 

[removed account4]

stand development usually takes a long time compared to rotary development.
for example, when i would rotary develop with caffeinol it would take about 12minutes,
but if i stand, it is more than double that ( and that is with a more active developer mixed in ) ...
since you are thinking of doing something a bit more conventional ( rotary ) the data sheets
are pretty accurate .. ( i still usually over develop by a few minutes ) ,

 

[2F/2F]

I would have no idea how to extrapolate a Jobo time from a standing development time. For one, they are almost 180 degrees apart as far as agitation goes; the Jobo using constant agitation and standing development using almost no agitation. As such, for the Jobo, I would start with what is suggested by Kodak for that film in rotary tanks. IMO this makes waaaaaay more sense than trying to come up with a starting point based on what you use for stand development.

 

[nworth]

Kodak's data guide for D-76 has times for rotary processing; http://www.kodak.com/global/en/prof...stry/bwFilmProcessing/d76.jhtml?pq-path=14029

I find the times Kodak gives in this reference questionable. They list times that are shorter than the times listed for tray development. My experience is that the developing time for the Jobo should only be about 10 percent less than for a small tank. In any case, for those trying to adjust to the zone system, you should do the appropriate tests to determine the proper developing times for your film, processor, and technique. The times for a small tamk (or about 10 percent less than those) are a good starting point, which you should adjust to give the contrast intended.

 

[edtbjon]

Daniel, when I read your post I wonder if you are using large "standing up" tanks with gallons of developer in it where you lift the film every minute or so, or possibly it has some kind of gas agitation system. In that case, you will puzzle most of us, as we define "stand development" as:
Developing in very dilute developer without any agitation for a very long time. E.g. Rodinal 1:150 for 45 minutes with one inital agitation for one minute and then 30 seconds agitation at 20 minutes. The rest of the time the small tanks stands still while you have a couple of cups of coffee/tea or so. (Rodinal is usually dilituted at 1:25 or 1:50.)

//Björn

 

[delphine]

Dan,

Jobo used to have online archives of the jobo quarterly which was published in the 90s; it was a very useful reference. They published articles about dev time, procedure and also, they published some testing that they did with pre-wetting.
The conclusion was that a pre-wet of 5 mins at the same temperature as your processing temperature, allowed to compensate for the constant agitation when using development time published for semi-agitation. They stressed out the importance of consistency and making sure that you do indeed stick to the 5 mins recommended.

As others have already recommended, use the 5 mins pre wet , see what you get and then add/substruct 15% dev time to fine tune if required.

I use the jobo with 5 mins prewet. I get great results, though I tend to add 15% dev time to FP4 and delta 100 with Paterson developer. I have had difficulties to get consistent results with Delta 3200 for some reasons, so I always hand process it with semi stand agitation.
HP5 in the jobo, is always spot on at the paterson's published semi stand agitation time with the 5 mins prewet.

Try the 5 mins prewet, see what you get, but don't forget, consistency rules !

 

[DanielStone]

Daniel, when I read your post I wonder if you are using large "standing up" tanks with gallons of developer in it where you lift the film every minute or so, or possibly it has some kind of gas agitation system. In that case, you will puzzle most of us, as we define "stand development" as:
Developing in very dilute developer without any agitation for a very long time. E.g. Rodinal 1:150 for 45 minutes with one inital agitation for one minute and then 30 seconds agitation at 20 minutes. The rest of the time the small tanks stands still while you have a couple of cups of coffee/tea or so. (Rodinal is usually dilituted at 1:25 or 1:50.)

//Björn

hi bjorn, thanks....

my meaning of stand development would probably be better suited to be called "inversion". this meaning a usual dilution of d76 1:1, using small SS tanks to process 120 and 135mm films.

I have decided to standardize on one film, TMY-2, and just use d76 1:1.
this way i can stop pulling my hair out when i mess up. well, the hair i have left that is

thanks everyone

dan

 

[2F/2F]

my meaning of stand development would probably be better suited to be called "inversion". this meaning a usual dilution of d76 1:1, using small SS tanks to process 120 and 135mm films.

In that case, I'd start with 15% less time than your small tank with intermittent hand inversion process, and see what happens.

I'd also read the instructions for the particular machine you are using, and read the data sheet for the film.

Stand development is a high-contrast-compensating technique that makes use of the fact that more exposed areas of the film suck the activity out of developer faster than less exposed areas. Therefore, when you reduce agitation, and use high dilutions of developer, the developer sits in one place, thus gets burned out on the more exposed areas areas before it gets burned out on the less exposed areas. Thus, development slows way down on the highlights, while it works at closer to normal speed on the darker areas.

 

[edtbjon]

...
my meaning of stand development would probably be better suited to be called "inversion". this meaning a usual dilution of d76 1:1, using small SS tanks to process 120 and 135mm films.

I have decided to standardize on one film, TMY-2, and just use d76 1:1.
this way i can stop pulling my hair out when i mess up. well, the hair i have left that is

Well then, that's sorted. And about the hair, been there done that.
Now for something serious. You have been given a lot of good advice which seems correct. (I use a Jobo CPP2 myself.) One thing to look out for is that the Jobo drums needs quite small amounts of chemistry, but there is a minimum amount of D76 needed for a film. Be sure to check that up, so that you don't use too little which for sure will mess your results up. (I don't remember the amount, but I know that it's an issue with D76 at 1:3 dilution.)

//Björn

 

[Sal Santamaura]

...there is a minimum amount of D76 needed for a film...(I don't remember the amount...

250ml of stock per 80 sqare inches of film.