Comments on: Black and White Film Developing Chemistry http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/ Cameras. Cats. Photography Thu, 22 Dec 2011 22:08:41 +0000 hourly 1 http://wordpress.org/?v=3.3 By: Ian http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/comment-page-1/#comment-123 Ian Thu, 04 Aug 2011 16:53:38 +0000 http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/#comment-123 Thank you for sharing all that info. It certainly makes a lot of sense now. I am pretty sure that saved me from a lot of noob mistakes. Hopefully, I won't waste too many rolls experimenting. Thank you for sharing all that info. It certainly makes a lot of sense now. I am pretty sure that saved me from a lot of noob mistakes. Hopefully, I won’t waste too many rolls experimenting.

]]> By: admin http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/comment-page-1/#comment-121 admin Tue, 02 Aug 2011 08:41:05 +0000 http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/#comment-121 @Ian, I think you misread the information here: there is no mention of ANY developing time for Neopan 400. The clearing time referred to ("2-2.5 minutes") is NOT the developing time- rather it describes the time for the Neopan emulsion to clear from translucent milky to colourless clear. Doubling that time will lead to a total fixing time of 5-6 minutes. "Clearing" is not the same, nor refers to, developing. Fixing time is NOT double the developing time. The recommended developing time for Neopan, as well as the recommended dilution is 1+50, developed 11 minutes at 20C. The values given at Digital truth are at best starting points from which an ideal developing time based on personal and practical preferences can be derived. The same can be said of developing tables provided by chemical and film manufacturers. "Accuracy" is relative- the recommendations given will always give something satisfactory, but may not necessarily be preferred personally. If the negative which results from following the tables' recommendations is too dense or too contrasty, the time can be reduced accordingly; if too pale, the time can be increased as well. Fixing time at 22 minutes is too long. Most films will clear in about 5 minutes even in plain thiosulphate fixers- so 10 minutes is about right for Neopan 400 in a fresh fixing bath. The 'doubling' factor involves doubling the CLEARING time to determine the total fixing time. 22 minutes will just lead to putting more hypo in the emulsion, and therefore, the need for a longer wash time. Regarding the preparation of paRodinal working solutions: DILUTION should only be done immediately before use. And only in the amount needed to fill the tank used for processing. Diluted paRodinal working solutions have an effective life of about 2 hours or less. I have received reports of people diluting the entire volume of the concentrate to make bigger working volumes and storing these for subsequent use. This is not proper way to use paRodinal- the stored diluted solutions will soon become ineffective. @Ian, I think you misread the information here: there is no mention of ANY developing time for Neopan 400. The clearing time referred to (“2-2.5 minutes”) is NOT the developing time- rather it describes the time for the Neopan emulsion to clear from translucent milky to colourless clear. Doubling that time will lead to a total fixing time of 5-6 minutes.

“Clearing” is not the same, nor refers to, developing. Fixing time is NOT double the developing time.

The recommended developing time for Neopan, as well as the recommended dilution is 1+50, developed 11 minutes at 20C.

The values given at Digital truth are at best starting points from which an ideal developing time based on personal and practical preferences can be derived. The same can be said of developing tables provided by chemical and film manufacturers. “Accuracy” is relative- the recommendations given will always give something satisfactory, but may not necessarily be preferred personally. If the negative which results from following the tables’ recommendations is too dense or too contrasty, the time can be reduced accordingly; if too pale, the time can be increased as well.

Fixing time at 22 minutes is too long. Most films will clear in about 5 minutes even in plain thiosulphate fixers- so 10 minutes is about right for Neopan 400 in a fresh fixing bath. The ‘doubling’ factor involves doubling the CLEARING time to determine the total fixing time. 22 minutes will just lead to putting more hypo in the emulsion, and therefore, the need for a longer wash time.

Regarding the preparation of paRodinal working solutions: DILUTION should only be done immediately before use. And only in the amount needed to fill the tank used for processing. Diluted paRodinal working solutions have an effective life of about 2 hours or less. I have received reports of people diluting the entire volume of the concentrate to make bigger working volumes and storing these for subsequent use. This is not proper way to use paRodinal- the stored diluted solutions will soon become ineffective.

]]> By: Ian http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/comment-page-1/#comment-119 Ian Mon, 01 Aug 2011 16:15:57 +0000 http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/#comment-119 Hello. It was mentioned here that Neopan 400 clears in 2-2.5 mins and fixes in 5-6 mins. What is the solution used for this dev time - 1+25 exposed at IS0400? The table on Digitaltruth for Rodinal formula listed the dev time for this solution at 6 mins so there is a difference of at least 3 mins. On the same table, dev time for Neopan 400 1+50; ISO 400 is at 11 mins (with 22 mins of fixing time - fixing time is double the dev time). Since I'm planning to do home developing using PaRodinal chemicals, do you have a chart that gives the approximate dev time and solution mixture? Is the Rodinal table on Digitaltruth accurate or is there any difference if any? Hello. It was mentioned here that Neopan 400 clears in 2-2.5 mins and fixes in 5-6 mins. What is the solution used for this dev time – 1+25 exposed at IS0400? The table on Digitaltruth for Rodinal formula listed the dev time for this solution at 6 mins so there is a difference of at least 3 mins. On the same table, dev time for Neopan 400 1+50; ISO 400 is at 11 mins (with 22 mins of fixing time – fixing time is double the dev time).

Since I’m planning to do home developing using PaRodinal chemicals, do you have a chart that gives the approximate dev time and solution mixture? Is the Rodinal table on Digitaltruth accurate or is there any difference if any?

]]> By: admin http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/comment-page-1/#comment-113 admin Fri, 29 Apr 2011 12:13:34 +0000 http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/#comment-113 Hi Nick, better bring your own paper. The local supply situation is rather shaky. Developers and fixers can still be sourced here. My developer is primarily formulated for film, but it can also be used for paper- the drawbacks being the stronger dilution (1+10) used, and the relatively faster oxidation (compared to the usual Dektol types). The fixer is good for both film and paper though. Hi Nick, better bring your own paper. The local supply situation is rather shaky. Developers and fixers can still be sourced here. My developer is primarily formulated for film, but it can also be used for paper- the drawbacks being the stronger dilution (1+10) used, and the relatively faster oxidation (compared to the usual Dektol types). The fixer is good for both film and paper though.

]]> By: Nick http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/comment-page-1/#comment-112 Nick Thu, 28 Apr 2011 11:43:02 +0000 http://www.zorkikat.com/black-and-white-film-developing-chemistry/276/#comment-112 Kumusta Jay, I'm coming to Phils in two weeks and was planning to set-up a dark room in my hotel room bathroom and do some crude black and white pinhole photography. Was just researching where I might be able to purchase some Developer/Fixers etc and found your details. Would appreciate you getting back to me with details regarding your pricing and beyond that any ideas where I can get some ilford photographic paper in Phils? or am I better to bring it with me? Thanks, Nick Kumusta Jay,

I’m coming to Phils in two weeks and was planning to set-up a dark room in my hotel room bathroom and do some crude black and white pinhole photography. Was just researching where I might be able to purchase some Developer/Fixers etc and found your details. Would appreciate you getting back to me with details regarding your pricing and beyond that any ideas where I can get some ilford photographic paper in Phils? or am I better to bring it with me?

Thanks,

Nick

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