How interesting to see this old thread and remember the folks who are no longer with us.
All of the changes are frustrating, but with the computer programs, a lot of the data is retained. Do the film test once, then you can adjust for paper changes rather quickly.
In the 4th Edition of the BTZS book he added the chapter on gradation which he was working on using the Matcher program in the Plotter program where he put a particular film curve with a particular paper curve to see the results. We used to show some prints with one negative printed on a number of different papers and to tones shifted all over the place, depending on the paper curves shape. He matched a light tone and a dark tone in each print. It's a really good chapter to read. I never heard anyone talk about it until Phil did. His first write up on gradation was for Photo Techniques and then added a chapter in his book on gradation. Phil was always trying new things. When I did workshops with him - he always added something new every workshop.
I've tried to make film testing more easy and user friendly with our film testing service. So now all you have to do is process some film. The processing times we use are 4, 5.5, 8, 11, and 16 minutes. I expose the film with a calibrated light source, read the densities of the 21 steps and enter the values into to Plotter software. You don't have to be real technical to do film testing, so now it's just the amount of time it takes you to process some film.
I have changed the testing procedure slightly. Now you process a roll/sheet of film for 4 minutes and send it to me for reading. I'm looking for a specific contrast negative and if it is too contrasty or not contrasty enough you can adjust the dilution of your developer and try again. I started doing this because I would get the test back and the dilution of the developer would be too strong and all the tests would be too contrasty and you would have to start all over again. If they were doing their processing in a Jobo processor that's a lot of time. I really didn't like calling up a photographer and saying that the film you just tested was too contrasty and we are going to have to run the whole test all over again. It doesn't take a lot of time to do one roll/sheet for 4 minutes. I now send out 7 rolls/sheets with each test so we have 3 tries to get the right developer dilution.
Once you find the proper dilution you process the other 4 rolls/sheets for the remaining times. You don't have to own a densitometer, but the plotter program or work on calibrating your light source.
When I first started doing film testing I had a photographer call me and he said I want to do your film testing but just give me the numbers. All he wanted was the normal film speed and developing times. He was a commercial photographer who at the time was shooting roll film 35mm and 120 and he said that he was able to produce better prints than his competition having calibrated his film.
The other thing you have to remember about Phil was that he love teaching and testing and that after he tested 9 film and 5 developers for the D-Max newsletter he went on to test the reciprocity for these films. The reciprocity information is incorporated into the Plotter program and the reciprocity information is also imported into the Expo/Dev software along with your film test information.
So I don't that investing some time in processing some film is a lot of work for doing a test. That's been one of the most fun things about doing BTZS workshops and teaching is helping photographers get better negatives which makes going into the darkroom a pleasure rather than a chore.
That was one of the best articles I ever read in that magazine.
His first write up on gradation was for Photo Techniques and then added a chapter in his book on gradation.
@fred, may I ask what is the contrast range you are looking for the 4 minute film. I guess it is something about some of two key steps in the film coming out from that development.
I just finished my paper grade test (using contact print) per your shipped items and Phil's book. Would start the film test (contact "print") plus the paper grade test (using projection method). As I am using Jobo, it takes quite a bit of time to do the test.
Hence, would interest to know any way to cut this a bit shorter the time.
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Originally Posted by frednewman
I can see the logic but never ran into this problem. Sometimes I end up having not quite enough contrast after 16 minutes, but then, I just go to 22 minutes to get that little bit extra.
Gradient vs development time graphs are non-linear. Unfortunately, sometimes the slope is increasing and sometimes it is decreasing. Consequently, judging the appropriate developer dilution from just one development time is difficult for most of us, unless we have done quite a bit of testing.
If I had to guess, I would say that a 4-minute development, resulting into a gradient of less than 0.35, is likely to need an increase in developer concentration if more than N+2 contrast is required and development times above 16 minutes are not desired. If the 4-minute development has an average gradient of above 0.45, one should think about a higher developer dilution or N-2 developments are impossible.
Then again, I had film/dev combos that had an average gradient of almost 0.5 at 4 minutes and still did not get more than N+1 at 22 minutes, because their gradient vs time curve is very flat (APX100 in Rodinal 1+50).
Last edited by RalphLambrecht; 10-31-2010 at 01:56 PM. Click to view previous post history.
And I am sure you are on the right track but I'm sure you meant
If I had to guess, I would say that a 4-minute development, resulting into a gradient of less than 0.35, is likely to need an increase in developer dilution if more than N+2 contrast is required and development times above 16 minutes are not desired. If the 4-minute development has an average gradient of above 0.45, one should think about a higher developer dilution or N-2 developments are impossible.
... a 4-minute development, resulting into a gradient of less than 0.35, is likely to need a [stronger concentration of developer]...
I totally get the idea, Ralph you have all the equipment in-house so you can control more variables.
Fred offers sensitometric/densitometric service to photographers without such equipment. In his case he's sending 7 sheets of sensitometer-exposed film to the photographer to process.
The 4 minute test is a sanity check. Assuming all the other variables are under reasonable control (temp, agitation, tank, etc.) -- developer concentration is a straightforward variable that can be tweaked and then locked down.
Then the photographer using Fred's service develops the series and both Fred and the photographer can expect reasonable data.
Thanks. I agree and corrected my typo.
I try to work with developing times between 4 & 16 minutes. The sequence of developing times used are 4, 5.5, 8, 11 & 16. This way normal developing times are usually between 6 & 9 minutes. If someone is testing film for platinum/palladium I sometimes extend the series - 22, 32 and even 45 minutes depending upon the results.
I've tried to use these procedures to keep the amount of work for film testing to a minimum. Film testing is like doing homework when you are in school and no one including us adults likes to do homework so the simpler it is the more likely film testing is the more likely photographer's will do it.
The original BTZS workshops that Phil Davis did were about 2 weeks. Everything was done by hand - this was before the plotter program. Actually plotting by hand works very well but is extremely time consuming. I have done the plotting by hand many years ago and have spoken to photographer's who have done it by hand.
I try to keep the proccessing time as reasonable, especially if you are processing film in BTZS tubes to 6 minutes. Processineg film past 16 minutes gets quite tedious. There is an article in the D-Max Newsletters where Phil increased dilutions of the developer and processed film out to about 64 minutes in the BTZS tubes.