Archived posting to the Leica Users Group, 1998/11/06
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Dear Erwin, Thanks for your informative response re Rodinal. Since you seem to be so knowledgable, let me ask another question. My impression is that Rodinal works best at 20 degrees C. It seems to loose some of the qualities that I like--gradiation, contrast, shadow detail, unblocked clean highlight, good edges, and grain that I can't began to see at 11X14 (28X37 cm)--if eveloped at a higher temp. I think this may be because the neg. is exposed to the potassium Sulfite for a longer period of time. This allows its action as a silver solvent to somewhat overcome grain formation. Ansel Adams talks about this affect in his book on the negative. Cheers, Joe Stephenson - -----Original Message----- From: imxputs <imxputs@knoware.nl> To: leica-users@mejac.palo-alto.ca.us <leica-users@mejac.palo-alto.ca.us> Date: Friday, November 06, 1998 2:37 AM Subject: [Leica] [lEICA] Rodinal topic Joe wrote: >Dear Erwin, >I am shocked to find myself in disagreement with you. I have always regarded >your comments and advice with awe. They have influenced some of my >purchases, and I have been pleased to find you were right. No need to feel shocked if you need to disagree with whomever. No one of us will be ever right on all topics. Still the Rodinal issue needs a bit elaboration. Presumably we are discussing the characteristics of Rodinal from different perspectives. Rodinal is a high acutance developer, preserving the grain structure in the emulsion and enhancing the edge effects by chemical actions, so visually pronouncing the grain clumps. At moderate enlargements this effect is fine (up to 8 to 10 times of the whole negative). Using APX100, which is a very good (if not the best film) at enlargements up to 10 times, and Rodinal gives you at 20x25cm (edging to 20x30cm)excellent image quality.And for many subjects it will suffice. This is what I said in my earlier message. If your experience covers the same criteria, there is no disagreemnt at all (and no reason for whatever shock :-)). But now look. My demands for leica negs are these: at least 20 times enlargements where the finest possible details recorded by the lens are clearly visible with excellent microcontrast. And I am talking of real life objects at a distance of at least 50 meters if not more, where the objects have very fine textural details. I target the hasselblad quality as the yardstick for Leica performance. When doing these comparison tests (long distance, very fine textures, 20 to 30 times enlargement) with plusx, fp4, d100, tmx, apx100 and a score of developers (xtol, d76, rodinal, tmax. fx39)I noted that up to 10 times enlargements every combination gave comparable results and the same characteristic curve (when suitably develeoped). The rightly famous long tonal range of APX is also available with other films. (APX is very good in this department, but not superior or inferior to other high class films. The PlusX btw is also excellent) Explanation of the good behavior of older tech films (PlusX, APX, TriX, FP4 etc? Classical emulsion make-up uses more silver per area and that literally shines. When enlarging to 30 times however some combinations broke up and the grain structure gave so much noise that loss of micro details became unavoidable. When using these exacting standards xtol/fx39 and d100/tmax showed their best. Upshot: our 'disagreement' might be a difference of quality standards. Now some luggers propose that a slow film and a tripod is a necessary combination and un-Leica-like. May I remind that a slow film (even apx25) in normal daylight gives exposure combinations of 1/500 at f/4,0 to 1/125 at f/8. If he luminance level drops we have our superior full aperture to cope with it. Even in lower level light I prefer apx25 and 1/60 at f/2 to any 400 at 1/250 at f/4. (for my type of pictures!) But for me Kodachrome 64 is the standard film and XP2 super gives me a turbo boost. Erwin