Hedd-wyn
22-Nov-2018, 21:54
Hi, As a relative newbie to 4x5 photography I have decided to go down the rabbit hole of film testing. I have become intrigued with the testing method as outlined in the BTZS 4th ed. book by Phil Davis. I have read the book and now have a very basic understanding of the testing, have gone through a great number of threads on this forum with regards to the subject and have also gone through the forum located at BTZS.org. There are still a few points I need to have clarified.
1. I am assuming that I don't have to do the initial test with an ASA 100 film like Delta in DDX 1:1 and that I can use HP5+ ASA 400 in HC-110
1:63 (correct me if I'm wrong but I got the impression that you test with an ASA 100 film first if you are going to use the Plotter program as
this is how you calibrate the program, otherwise you can test what you want)
2. I will be using my enlarger for contact printing the step wedge. For ASA 100 film the book says initial testing should be f11, and EV4 @ 0.4
sec. therefore for ASA 400 I should use f11, and EV2 @ 0.4 sec. Correct?
3. I have a 31 step wedge that I will be using as I don't have a 21 step. The book calls for a 21 step wedge but on the BTZS forum site the
question of being able to use a 31 step was asked and Phil Davis replied that he hadn't done it himself, but didn't see why not and listed the 21
steps out of the 31 that he would use for the plotting. I would like to hear from someone who has used a 31 step wedge to find out if it
provided a satisfactory result.
4. It is also my understanding that Fred Newman at the View Camera Store now tells clients that are going to use his film testing service that
they should run the 4 minute film first of all and see if it shows an SBR of approximately 9. If over or under, the developer dilution should
changed and the 4 minute test done again. e.g. if the SBR is too contrasty (SBR 7) then the developer dilution should be increased. If the SBR
is too high (SBR 10) the dilution should be decreased. Once the SBR of 9 is achieved, then all 5 films are exposed and developed at that
dilution. This is where I need help. I am assuming that when he says the film should exhibit an SBR of 9 he means it should show a range of 9
stops which on a 21 step wedge would mean that there should be 18 steps visible, each step representing 1/2 stop. Correct? I would have e-
mailed Fred but the website says he is away until Nov. 29/18 and I would like to start testing.
Thanks for your input. Feel free to offer any other gems not in the book that will make the testing go a little easier. I know I could use the testing service at the VCS but that wouldn't give me the satisfaction of doing it myself. I'll eventually buy the Plotter and Expo/Dev programs once I can get satisfactory results this way. An acquaintance thought that a lot of the PTSD found in photographers could be related to BTZS testing! I'll see.
1. I am assuming that I don't have to do the initial test with an ASA 100 film like Delta in DDX 1:1 and that I can use HP5+ ASA 400 in HC-110
1:63 (correct me if I'm wrong but I got the impression that you test with an ASA 100 film first if you are going to use the Plotter program as
this is how you calibrate the program, otherwise you can test what you want)
2. I will be using my enlarger for contact printing the step wedge. For ASA 100 film the book says initial testing should be f11, and EV4 @ 0.4
sec. therefore for ASA 400 I should use f11, and EV2 @ 0.4 sec. Correct?
3. I have a 31 step wedge that I will be using as I don't have a 21 step. The book calls for a 21 step wedge but on the BTZS forum site the
question of being able to use a 31 step was asked and Phil Davis replied that he hadn't done it himself, but didn't see why not and listed the 21
steps out of the 31 that he would use for the plotting. I would like to hear from someone who has used a 31 step wedge to find out if it
provided a satisfactory result.
4. It is also my understanding that Fred Newman at the View Camera Store now tells clients that are going to use his film testing service that
they should run the 4 minute film first of all and see if it shows an SBR of approximately 9. If over or under, the developer dilution should
changed and the 4 minute test done again. e.g. if the SBR is too contrasty (SBR 7) then the developer dilution should be increased. If the SBR
is too high (SBR 10) the dilution should be decreased. Once the SBR of 9 is achieved, then all 5 films are exposed and developed at that
dilution. This is where I need help. I am assuming that when he says the film should exhibit an SBR of 9 he means it should show a range of 9
stops which on a 21 step wedge would mean that there should be 18 steps visible, each step representing 1/2 stop. Correct? I would have e-
mailed Fred but the website says he is away until Nov. 29/18 and I would like to start testing.
Thanks for your input. Feel free to offer any other gems not in the book that will make the testing go a little easier. I know I could use the testing service at the VCS but that wouldn't give me the satisfaction of doing it myself. I'll eventually buy the Plotter and Expo/Dev programs once I can get satisfactory results this way. An acquaintance thought that a lot of the PTSD found in photographers could be related to BTZS testing! I'll see.