adjusting dev time for a jobo processor

[starless]

My development time for Trix in a small tank (2 rolls) is 9 min. Now I am about to have a few rolls developed in a Jobo rotary processor, and I remember someone saying that time should to be reduced.

Does anyone know what this is all about? Sorry if I can't be more specific.

 

[Jaans]

My development time for Trix in a small tank (2 rolls) is 9 min. Now I am about to have a few rolls developed in a Jobo rotary processor, and I remember someone saying that time should to be reduced.

Does anyone know what this is all about? Sorry if I can't be more specific.

I used that Jobo rotary system extensively for about six months. I had joined a dark room and decided to switch from hand processing to cut down time. However, that was a mistake.

Personally, I would not recommend using a rotary system for black and white. The negatives that I obtained were no comparison to the ones done by hand that had time in between agitations. Even though you are using only 240ml of solution (D76 1:1 - 120ml D76 and 120ml water) this constant development doesn not allow time for the shadows to develop fully. This is because you have to cut down about 15% of your total processing time. I also recall Ansel Adams (not that I am sycophant) recommending hand over this system.

I also found that the temperature will rise higher faster as there is more energy generated with this electronic perpetual system.

So, on a sunny days with high contrast negatives, hand processing will always be preferable. On a cloudy day, then the system is good, but you have to test your speed controls.

Another reason that I don't like using this system, was that I like to monitor my tanks temperature by sticking a thermometer down its neck every few minutes. You can't do this when it is laid out horizontally. In this case of the system you have to trust that your water temperature is working. I find it easuer inverting it vertically in a cool water bath for those hot summer days, than monitoring the larger bath of the jobo processor. There is a little gauge to tell you the temperature, but I find the whole thing inconvenient.

So, in the end it all comes down to control. I love the control that hand processing gives you. I also love the negatives that hand processing gives you with the full 480ml of solution (240ml D76, 240ml water).

Anyway, they are my personal observations. I would definetely stick to hand developing.

 

[starless]

Thanks for you reply.

So even even you reduced time by 15% the shadows did not come out well? But the highlights were properly developed?

I am using the same combo - Trix@200 in d76 1-1, however I just don't have the time and facilities to develop film anymore.

After reading your comments I am seriously considering NOT sending my film to the lab for rotary processing.

 

[Jaans]

Just remember that if you are shooting at EI:200, then you will have to cut another additional 10% of your development time.

That time reduction of 15% I stated in my initial post applies to TRI-X at EI:400. So, if you are shooting at 200 then you will have to cut your time by a total of about 25%, which I think is too short to allow your shadows to fully develop.

Its not a question of whether your highlights will be fully developed - infact they will be the fastest thing to 'cook' or blow out. Perhaps some may find it hard to pick the difference between the rotary and hand developed film, but for scenes shot at EI:200 on a sunny day with strong highlights, I think that hand developed film is definetely better.

I also found that the shorter times give a smoother feel to the film with less perceptible grain. However, this result is detrimental as the look is flat with no perceived depth to the image that the grain will give. The highlights can be blown out with little shadow detail. Remember that developer is almost contantly hitting the negative during the process as it rotates.

I would think that the processor is better suited to c-41 or slide.

If you give your film to the lab, then just remember that you are surrendering control and have to hope that their chemicals are fresh, they are accurate with their thermometer, they are careful not to scratch film/with fingerprints, they use solution to prevent drying marks.

It all comes down to how important the film is and whether you have the skills to do it yourself or learn in the interim.

 

[rodgersfoto]

Folks: I have been using Jobo for over 15 years!. No Problems. Use a brief pre-wash-I use five minutes- and the times are the same as before. Just allow solutions to reach temp. and all will be fine.
Fotorr
http://rodgersphoto.blogspot.com/

 

[venchka]

Folks: I have been using Jobo for over 15 years!. No Problems. Use a brief pre-wash-I use five minutes- and the times are the same as before. Just allow solutions to reach temp. and all will be fine.
Fotorr
http://rodgersphoto.blogspot.com/

Right on! Rotary & Xtol 1:3 is AWESOME!

 

[starless]

My calibrated time for EI 200 in D76 1-1 is 9 min in a small tank. Therefore if I choose to switch to the Jobo processor, I'd have to reduce it to about 8 min, right?

I guess the only thing I could do is try a roll and see how it comes out...

 

[Roger Hicks]

My calibrated time for EI 200 in D76 1-1 is 9 min in a small tank. Therefore if I choose to switch to the Jobo processor, I'd have to reduce it to about 8 min, right?

I guess the only thing I could do is try a roll and see how it comes out...

Should work perfectly. I've been using Jobos for years without any of the problems others mention. Shadows actually develop slightly more with continuous agitation than with intermittent. That's not just my opinion: Ilford's research people say the same (or said the same).

It's important, too, not to pay to much attention to others' experiences. I find that in order to get negs that print the way I like on grade 2 I need to give rather more development than most people. This doesn't mean that YOU will do better with (say) 8-1/2 minutes, but it does mean that you shouldn't pay too much attention to someone who tells you that you will do better with 7-1/2. Either person may be right; the only one who is absolutely and without doubt wrong is the one who tells you that his is the only answer.

So yes, try it.

Cheers,

R.

 

[starless]

Thanks everyone for the advice.

Will try a roll in the Jobo for 8 mins.
If it doesn't come out well - it will back to the bath/darkroom for me🙂

 

[venchka]

Personal testing. Don't shoot film without it.

 

[rxmd]

I normally cut 20% off the time when doing rotary processing, rounded down because of the extra time involved in handling the tank, putting it in and out of the processor etc. In your case I'd probably try 7 minutes for a start.

Depending on what Jobo processor you have, even if you develop by hand you can still use the processor for fixing - frees up your hands for ten minutes or so.

 

[Gid]

I have a CPE2 with lift. Stated dev time less 15% works for me. I don't even fill the bath now, just get the temp of a basin of water around 20 degrees C, mix up dev, stop and fix then off you go, followed by 8 x 30 second washes with water at the same temp - last one with some photoflo.