Re: Obsidian Aqua, catechol staining developer
You are right. It's more important to ensure that the developer doesn't get into the fixer too much. I think a pre-soak although not recommended by Ilford is still very well worth doing. I never had streaks or air bells since adding a pre-soak to my routine...
RR
Re: Obsidian Aqua, catechol staining developer
I use one fixer for several films. I have heard that film that has been developed in a pyro or other staining developers, can reduce stain in some fixers... but I have no experience or even been a witness to it. I've used the same type of fixer for years, and have used 4 different staining developers, including PMK and ABC Pyro. I use a regular stop bath, containing either vinegar or citric acid. People who use TF4 fix are not required to use an acid stop bath. Plain old water is fine.
Re: Obsidian Aqua, catechol staining developer
I believe that a mild acid not only stops development quickly, but also helps prolong the life of acidic fixers.
If you use an alkaline fixer, you can still use a mild acid stop bath if you are concerned about arresting development immediately. Plain water will stop development, but more gradually. If you time your development down to the second, then a mild acid stop is not a bad idea, whatever fixer you use.
Citric acid is affordable and has no offensive odor.
Re: Obsidian Aqua, catechol staining developer
I stopped using acid stop baths when I used ADOX CHS Art Films, as ADOX recommended to use only water. The emulsions were delicate it would seem. Anyway it worked so well I thought I'd eschew acid stop baths for the other films I use and I have not found any reason to regret that. Consistency seems to be the key to success. Find out what suits yourselves and then stick to it. I'm sure the developer does carry on working for a few seconds after pouring out the developer and pouring in the water but as long as all this is the same each time you work then you will get consistent results. It's only when you change things that inconsistency can creep in. If your film and stop bath combination has worked for you then there is no need to change it because you have changed your developer. Particularly if it is a one-shot developer and not going to be re-used.
RR
Re: Obsidian Aqua, catechol staining developer
Quote:
Originally Posted by
Regular Rod
I stopped using acid stop baths when I used ADOX CHS Art Films, as ADOX recommended to use only water. The emulsions were delicate it would seem. Anyway it worked so well I thought I'd eschew acid stop baths for the other films I use and I have not found any reason to regret that. Consistency seems to be the key to success. Find out what suits yourselves and then stick to it. I'm sure the developer does carry on working for a few seconds after pouring out the developer and pouring in the water but as long as all this is the same each time you work then you will get consistent results. It's only when you change things that inconsistency can creep in. If your film and stop bath combination has worked for you then there is no need to change it because you have changed your developer. Particularly if it is a one-shot developer and not going to be re-used.
RR
Question, do you know how long the water needs to be there before the film fully stops developing?
Is it 10 seconds or 30 seconds or 2 minutes? With water I mean...
Ilford recommends 1 minute for ilfostop but I always rinse once or twice with water after the dev anyway so as to make the stop last longer without dev contamination. So, by the time the ilfostop gets to the film, have I already stopped it?
Re: Obsidian Aqua, catechol staining developer
Quote:
Question, do you know how long the water needs to be there before the film fully stops developing?
Film would need to be well soaked in a water bath/rinse with several changes of water so that none of the developer is carried over to the fix. I usually did several rinse/agitate/dump cycles for two minutes. I prefer an acid stop bath as it will extend the life of your fix.
Quote:
So, by the time the ilfostop gets to the film, have I already stopped it?
Yes. It's pretty immediate. I remember using Ilfostop when I lived in Japan. It's mildly acidic (hence ILford's recommends a 1 minute bath) and less odour compared to their rapid fixer.
Re: Obsidian Aqua, catechol staining developer
Quote:
I stopped using acid stop baths when I used ADOX CHS Art Films,
When I used Kodak IR sheets films, I used a very mild acid stop bath containing 1 tsp of citric acid. A regular acetic acid stop bath almost always resulted in pinholes in the emulsion. I also found that Efke 25 preferred citric acid.
Rod, how did you like Adox CHS?
Re: Obsidian Aqua, catechol staining developer
Quote:
Originally Posted by
StoneNYC
Question, do you know how long the water needs to be there before the film fully stops developing?
Is it 10 seconds or 30 seconds or 2 minutes? With water I mean...
Ilford recommends 1 minute for ilfostop but I always rinse once or twice with water after the dev anyway so as to make the stop last longer without dev contamination. So, by the time the ilfostop gets to the film, have I already stopped it?
Pour in. Four agitations left right, four agitation back front. Pour out. Pour in more. Four of each as before. Pour out. Pour in Fixer. Start clock. Four of each repeated until first minute is up. Stand one minute. Four of each. Stand until that minute is up. Four of each again. Stand again. Keep doing it until the five minutes is up. Pour out fixer into jug. Wash according to Ilford method. For sheet film in the Paterson Orbital it is still the Ilford method but with the four of each agitation just continued for 10 seconds, then 20 seconds, then one minute, then another minute and two more minutes after that. Then a stand in water with 0.5ml of Mirasol in 500ml of water for one minute. Very slight agitation, more a roll round with the lid off so I can see that I make no bubbles, about every 15 seconds. Then carry tray and film through to drying cabinet. Clip up the film by a corner, still in the water. Lift it out smoothly and hang it up to drip dry. After five minutes blot the great big drop off each lower corner with a tightly folded tissue so that only the very edge of the corner actually gets touched. Then dry it.
RR
Re: Obsidian Aqua, catechol staining developer
Quote:
Originally Posted by
Andrew O'Neill
When I used Kodak IR sheets films, I used a very mild acid stop bath containing 1 tsp of citric acid. A regular acetic acid stop bath almost always resulted in pinholes in the emulsion. I also found that Efke 25 preferred citric acid.
Rod, how did you like Adox CHS?
I only used CHS in 120. I loved the CHS 25 ART for its tonal range, reasonably fine grain and the way it responds to both 510-PYRO and OBSIDIAN AQUA. I did however hate the substrate! It was very lively and loading it into the spiral was always nerve wracking. After processing it remains a nightmare, spiralling into cylinders when I cut it up to 6x12 negatives. Getting it into a negative holder was always a struggle, darkroom gloves were a great help as they let me grab the film anywhere instead of by the edge only. The best negative holder for this film uses ANR glass to lay it down flat. I would gladly put up with all these torments for the results it gave. I currently am down to my last 7 frames of CHS 25 ART...
Anyway I liked it so much I am about to try CMS 20 with OA. If I can have some nice tones I will be happy again...
:D
RR
Re: Obsidian Aqua, catechol staining developer
Quote:
Originally Posted by
StoneNYC
Ilford recommends 1 minute for ilfostop but I always rinse once or twice with water after the dev anyway so as to make the stop last longer without dev contamination.
I use a SB with indicator; however, I have never had the indicator react. I do change my SB about every month. The SB I use is 1:19, so a one litre bottle (under $20) lasts over 18 months at a cost of approx. $1/month.
As such, I don't understand why you'd risk your images to save so little $$$.