I know that if I use Kodak Xtol I need to have 250ml of stock Xtol per 8x10 film equivalent processed for uniformity and repeatable performance. Yes, I know JOBO says 100ml stock but others say 250 is the minimum. When mixing Rodinal, what is considered the minimum of the syrup from the jug needed per 8x10 film unit to assure complete and even development?

-- Dan Smith (shooter@brigham.net), May 14, 2001

Answers

According to the "The film developing cookbook" you should have at least 500 ml rodinal for one 8 by 10 film unit.

Sergey

-- Sergey (roksyserg@aol.com), May 14, 2001.

I've routinely used Rodinal 1:50 @255ml or so per 80 sq in without any odd results or unpredictable development changes. That's simply 5cc Rodinal concentrate plus 250ml water.

Excess aeration in the Jobo _may_ be a concern; I don't know. I've been using it with 4x5 and 8x10 HP5+ in Unicolor drums.

-- John Hicks (jbh@magicnet.net), May 14, 2001.

I use Rodinal almost daily at 1+100 for 35mm and 120. That works out to 3mls of Rodinal to 300mls of H2O for a roll of 35mm and 5 mls of Rodinal to 500mls of H2O for a roll of 120. The difference in total volume of stock differs due to the size of the container used for each film. NOTE: I sometimes process Agfa APX 100 120 and 35mm togeather in the same container. So as not to confuse myself I still use 1+100 but use the 5mls Rodinal to 500mls of H2O for each roll regardless of format size. I _do not_ see any difference in my negs when I compare the 3mls of Rodinal to 300mls of H2O negs to the 5mls of Rodinal to 500mls of H2O negs...jim

-- Jim Vanson (p645n@hotmail.com), May 15, 2001.

Dear Dan,

in our technical data we mention that 500 ml concentrate of RODINAL will last for 50 films (135-36). That means that you need 10 ml concentrate to process 1 film. It does not matter what the dilution is. Important is that you are using 10 ml concentrate. For example if you are processing with a dilution of 1+50 than you need 10 ml concentrate plus 500 ml water so that you will have in total 550 ml solution to process your film. Why is it importatn to take 10 ml because these 10 ml contain the amount of substances which will be used to process your film correctly and with reproducible results. It can be that you will get good results with less than 10 ml as mentioned in one answer but to be sure we recommend 10 ml. I hope this will answer your question. If you have further questions please do not hesitate to contact me.

Kind regards Wolfgang Holz Product Manager Marketing Chemicals

Agfa-Gevaert AG

-- wolfgang holz (wolfgang.holz.wh@germany.agfa.com), May 15, 2001.

Dear Dan,

although I mentioned the amount of concentrate which is needed for a 135-36 the quantity will be the same for 8x10 film since the unit of square measure is near the same - 551 cm² for the 35 mm film and 516 cm² for the 8x10 film. The correct ammount would be 9,36 ml concentrate but I think to measure this might be a bit difficult.

Kind regards Wolfgang Holz

-- wolfgang holz (wolfgang.holz.wh@germany.agfa.com), May 15, 2001.

My experience is that 6.6cc of Rodinal concentrate does not properly develop 4 sheets of 4x5 in a JOBO drum with 330mL of total solution (nominal 1:50 dilution).

I would use 10cc stock Rodinal MINIMUM.

-- John O'Connell (boywonderiloveyou@hotmail.com), May 15, 2001.

I normally use 5ml syrup to 500ml water for one 120 roll of APX 25. Gives me a nice full range of tones.

-- David Parmet (david@parmet.net), May 15, 2001.

Wolfgang Agfa has two kinds of Rodinal, the regular one and a Rodinal-Special ( in 125ml bottle )

Now, what exactly is the difference between Rodinal and Rodinal Special ?

Rodinal Special is stated as "Fine Grain developer"

What makes it "fine grain" ?

It seems that Rodinal Special contains Hydroquinone, and Rodinal does not, but AFAIK, hydroquinone is not a fine grain agent.

Does Rodinal Special contains sodium sulfite ?

-- martin tai (martin.tai@capcanada.com), May 19, 2001.

Does double or triple the amount of Rodinal develops better film

Wolfgan, another question

There is a school of practice insists that move developer makes better negative. For example, if 10ml is the miniumum necessary for one roll of 135-35 in a 250ml tank, then using a large tank containing 500mml with 20 ml of Rodinal is said to produce better negative.

Is this "more developer is better " practice supported by scientific evidence ?

-- martin tai (martin.tai@capcanada.com), May 19, 2001.