Development times using Jobo Expert Drum

[mark_lipton]

I will be developing 4x5 T-Max 100 sheet film (exposed at a speed rating of 64)in a Jobo 3006 Expert Drum with a Uniroller base. I would appreciate some recommendations from anyone who has used this setup as to appropriate development times and temperature for a range of N-3 through N+3. Developer will be T-Max RS diluted 1:9. Thanks for your help.

[tim_kimbler]

Try the JOBO home page. I use the same set up your using. I follow

their recomendations. TMAX dose good for me, but I get better results

with TRIX. I use XTOL 1to1 developer.

[christopher_cline]

Hi Mark

 

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I use a 3006 Expert Drum with a CPA-2 set to a 3 1/2 rotation speed. I

develop in T-Max RS @ 24 degrees Celsius with a 5 minute water

presoak. I got the times I use from Don Kirby and Stu Levy, and they

work very well for me. My dilutions are made straight from the syrup

concentrate (with the B packet poured into the concentrate bottle).

1+9 dilution for me means 1 part syrup concentrate plus 9 parts water.

 

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Development Dilution Time

 

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N-2 1+19 14m 0s

 

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N-1 1+9 8m 30s

 

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N 1+9 11m 30s

 

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N+1 1+9 16m 0s

 

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N+2 1+4 11m 0s

[sal_santamaura]

When folks say they're using speed 3 1/2, what drum rpm does this

represent on your machine? Jobo's Web site includes a page

 

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http://www.jobo-usa.com/faq/CPP_Speed_Settings.html

 

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which indicates that different rotational speeds result from the same

settings depending on which motor is installed. I've asked Jobo

directly about this because they have a Sexton article on their site

that also recommends speed 3 1/2 which was written in 1994, possibly

before the motor change. When they respond I'll post the answer here.

[sal_santamaura]

I asked Jobo whether, based on their speed setting page (referenced in

my above post), I should be using the "F" setting on my new CPA-2 to

achieve the rotational speed Sexton was getting in 1994 by using 3

1/2. Jobo's answer is:

 

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"Your analysis seems correct to me. The most important factor is the

speed itself, not the printed marks on the speed dial. To determine

the setting for 50 rpm's for YOUR processor, put the drum on the lift

with water inside to simulate a typical chemical load. Swing the

3-fingered switch (behind the cog on the motor shaft) out of the way,

so the motor will not reverse. (We only use the single direction for

determining speed, never for real processing.) Set the speed dial to

F and start a stop watch, and count the drum as it turns. If indeed

your particular processor happens to run at 46 when set to F, that

will be great! If it's a little farther from 50 rpm's, you might

adjust the speed control and check its speed again until you are real

close to 50. Then take a pencil and make a mark on your speed dial,

and THAT is your setting for 50."