Here is one of the tests. Carbonate produced slightly higher emulsion speed. At first glance it looks more significant than it is, but you can see a significant portion of the density increase is just more fog, which is to be expected. When I high pH is used for bath B, a formula typically will require balancing with KBr.
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Michael, thank you for posting these results and those linked in post 52.Here is one of the tests. Carbonate produced slightly higher emulsion speed. At first glance it looks more significant than it is, but you can see a significant portion of the density increase is just more fog, which is to be expected. When I high pH is used for bath B, a formula typically will require balancing with KBr.
Also note of course the results might change with a different bath A, or a non-active bath A etc.
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Michael, thank you for posting these results and those linked in post 52.
I'm not claiming much expertise in this but it appears to me that to obtain maximum EI together with maximum development of the shadows, Carbonate combined with no agitation should be used in part B.
I am encouraged in this view by the fact that AA in his book "The Negative" p229-30 recommended no agitation in Part B for good shadow development.
Interesting. I definitely need to save some $$ and get a densitometer.
Hi Alan. Bill Troop also suggests C41 developer for Techpan (and amazing ISO 100) at the back of the book which I have never tried. I have ImagelinkHQ (Son of TP), Bluefire, RO80s and FK25 but stick with what I know. Keep up the good work, as these films seem to be like a honeypot to amateurs.
while it is not necessarily difficult to optimize a developer for a given emulsion, it is entirely another matter to make a formula that delivers excellent results with a wide variety of emulsions.
Apart from Adox's special purpose developers like Adotec and Silvermax which are optimised for specific films, are there any such optimised developers for current films like Tri-X or Acros? Not necessarily commercial developers.
Raghu, interestingly some folks are using the Silvermax Developer specifically for Acros with good effect. Not exactly what you were asking but related.
Thanks Karl! Would like to know more on this. Can you give some pointers?
I am trying to remember where I was reading this and can't find it. However, looking at the ADOX Silvermax developer data sheet, there are now official times for a few more films, including Acros: http://www.adox.de/Technical_Informations/TA_SILVERMAX_EN.pdf . Here's a good example from Flickr of what it looks like: https://www.flickr.com/photos/129240325@N07/25113184527/
Progress to date:
After 7 rolls through MDS-1, I am aware that there is development in the carry-over to part B. Exhaustion of developer in part B, sometimes cited as a property of 2 bath developers, is never reached.
However, since I am using part B composition believed close to that of Emofin (see Link, post 13 above) and Emofin is said to process 15 rolls/L, the approach seems valid.
Eventually the contrast will increase to a level unacceptable for scanning/silver printing and new part B will be needed. But Emofin was used to develop films for silver gelatin printing for 70+ years.
Notably the density obtained using MDS-1 is much higher than that obtained using MDS-1 part A with 12g/L Metaborate part B (Thornton) and higher than that with 12 g/L Metaborate + 12g/L Sulfite part B.
I hope to report eventually on the number of Aviphot films that can be put through MDS-1 before the contrast is unacceptably high.
Scanning and processing gives an increase of about 2 stops on the results given by Henning, see eg Adox HR-50 at EI = 100:
https://www.flickr.com/photos/98816417@N08/51221997316/in/dateposted-public/
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