JOBO CPE for processing B&W HP5

Hi,

What are the general rules for processing a few films at a time?

Do I need to multiply the quantities of chemicals by the numbers of films to be

processed ? Prolonge development time and or increase chemicals quantities?

I have 15 rolls of HP5 MF waiting for being processed..

Thanks for your advise also in genral method for processing several B&w films this

way.

Jean-Claude

This depends on the developer you'll be using. All developers have a maximum area of film to be developed per litre, or minimum quantity of developer per film, depending on how you look at it.

Suggest you read the instructions that came with the developer carefully, or download the data from the maker's website.

For example: maximum number of 120 films/litre in microphen is 10, with the time to be extended by 30% after 4 films, 40% after 5 films and 90% for film number 10! OTOH, the instructions for HC-110 recommend a minimum of 20 to 25ml concentrate per film, regardless of dilution.

A one-shot developer like HC-110 would obviously be more consistent for your particular application Jean-Claude. Using dilution B (1+9) to develop 4 films, you'd need to use 1litre of made-up developer. Ignore Jobo's recommended amounts of developer, because these don't take any account of solution exhaustion.

i use a cpe-2 to process as much as five rolls of hp5+ together. you just have to use

the amount especified in the tank for rotation. remember that if you process only 3 rolls

in a five roll tank, you will have to add to empty spirals to complete five. check the

jobo web page to get a manual.

Hi Joe and David,

I made a test roll and obtained my best results with 12.5 ml HC110 (dilution B) developed for 5 minutes. Details both in black and white parts.

LOGICALLY, if I wish to process 4 films I would need 50 ml HC110 + 1.55 liter of water. No?

You say 20ml per film , so would need 20x4x=80x31=2.4 liter !

There is something I really do not understand.

Thanks for your help.

Jean-Claude