Newbie Jobo questions

Ales' · 2025-10-12T05:45:28-0400

Hi, I just ordered Jobo cpa2 processors without drums to process my color and black and white film.
I know with tanks to get for 8x10 and 7x17 but dont know what to get to develop 12 sheets of c41 film at once.
But my most important quiestions are how to time developing?
I plan to use bellini 1 liter kits
The capacity for e6 is 10 sheets of e6 film,how do i calculat time if I want to develop film in 2 rune of 5 sheets, how long i have to develop for first and second run?
My understanding is i have to develop shorter because of contiuons agitation and make the second run longer because of developer exaution. But how much shorter and how much longer?
Sorry if the question where already ansewered

koraks · 2025-10-12T06:13:18-0400

Ales' said:
what to get to develop 12 sheets of c41 film at once.

4x5?
I'm not aware of any 12-sheet capacity Jobo tanks.

Ales' said:
if I want to develop film in 2 rune of 5 sheets, how long i have to develop for first and second run?

It'll be up to you to determine how much to extend (if at all) the first developer time for the second batch of film. With a little bit of luck you can use the same time. If you find the results deviate from the first batch, you may have to extend the time by a few percent. I don't think there's a specified solution for this; it depends per use case.

Ales' said:
My understanding is i have to develop shorter because of contiuons agitation

Color development times are usually specified for (near-)continuous agitation. I would not cut back the development time, especially not for E6. I see some people extend the first developer time depending on the film/chemistry combination they use.

Ales' · 2025-10-12T06:20:32-0400

koraks said:
4x5?
I'm not aware of any 12-sheet capacity Jobo tanks.

It'll be up to you to determine how much to extend (if at all) the first developer time for the second batch of film. With a little bit of luck you can use the same time. If you find the results deviate from the first batch, you may have to extend the time by a few percent. I don't think there's a specified solution for this; it depends per use case.

Color development times are usually specified for (near-)continuous agitation. I would not cut back the development time, especially not for E6. I see some people extend the first developer time depending on the film/chemistry combination they use.

Ive seen 6 sheets reels, i think there is a tank where i can stuck two of this reels

koraks · 2025-10-12T06:43:54-0400

OK, so we're talking about 4x5" I assume.
I see what you mean; this would be in the 2500 series. See e.g. the #2560 tank, which should indeed fit two reels. I do not see this tank listed anymore on the jobo.com website, but it's still on the jobo-usa.com website and it may pop up here and there on the 2nd hand market.

gary mulder · 2025-10-12T07:09:40-0400

18 sheets

ChrisGalway · 2025-10-12T15:35:44-0400

Ales' said:
My understanding is i have to develop shorter because of contiuons agitation and make the second run longer because of developer exaution. But how much shorter and how much longer?

Sorry if the question where already ansewered

I would definitely NOT use a first development time shorter than the recommended 6min15sec @ 38degC. At least start with the recommended times for all baths, they are for continuous agitation I believe. There is inevitably some trial and error with this alchemy, but you will quickly get it all perfect.

mshchem · 2025-10-12T19:56:01-0400

Agreed! Use the recommended time for 1st developer, there's a lot of different recommended times out there. I use 6'30". I definitely would try it with a single sheet 1st.
The 4x5 reels work great if you can get them loaded
I use IR goggles.
I believe that the increases in development times are published for subsequent batches. I would be cautious. With E6 1st developer time and temperature is extremely critical.
When I shoot 35mm I use auto bracketing of 1/2 stop (Nikon F5) this has saved me many times!

One thing nice about the sheet film reels is the ease of washing. Bad thing is loading.

Newbie Jobo questions

Ales'

koraks

Moderator

Ales'

koraks

Moderator

gary mulder

ChrisGalway

mshchem

Newbie Jobo questions

Ales'

koraks

Moderator

Ales'

koraks

Moderator

gary mulder

ChrisGalway

mshchem

Privacy & Transparency

Privacy & Transparency