HP5, a really flexible film.
I rated HP5 at five different speeds, all on one roll of film!
Recently I was collating various notes I had around the darkroom; Some were stuck on the wall, some were in a notebook, some were in a loose pile and some were just in my head. I thought it was time to tidy it up and keep it all in one place, clearly laid out.
One of the scraps of paper had a rough grid drawn out and a range of options for HP5. I had worked out the development times for HP5 rated at a range of speeds from 100 to 1600. I mentioned this to a friend and he asked me what the advantages were with lower ratings, so I decided I would run a test and make prints off each set of negatives to show exactly what happens to grian size and tonality.
My original intention was to just shoot five sheets of HP5 in 5x4 and develop them according to the chart, but I realised that there would be no discernable difference in grain size on a 10x8 inch print.
To make it relevant to the majority of film shooters and to get a better understanding of the effects, I realised that 35mm would be the best option.
I figured that it should be possible to do a range of exposures and to repeat them until I had five sections of film that I could cut up and process individually. My idea was to expose frame one as 1600, frame two as 800, frame three as 400, frame four as 200 and frame five as 100. This would be done five times with a blank frame between each range of exposures. The film could be cut at the blank frame and that section loaded into a tank and given a particular dev time.
The main problem I had was how to find the blank frames when I was loading up in total darkness. I remembered hearing once about a french phototographer who used to process short sections of film to practice the zone system with 35mm. He would wind on to the next frame, put the camera on B, remove the lens, then hold the shutter open while he put a small sticker on the film at the back of the camera. The shutter was closed, the film wound on and another bit of tape would be put on the film the next time he had a section that needed different processing. It’s a fiddly thing to do, but it gives you options with 35mm film. The sticker has to be placed gently on the film, because too much pressure would allow light further into the camera, fogging the frames either side.
I decided to emply this method to mark the blank frames. I worked out my exposures for five different film speeds and wrote them out.
Camera on tripod, focus lens, then expose the sequence;
1600. 1/4. f16
800. 1/2. f16
400. 1s f16.
200. 1s f11
100. 1s f8
Blank frame (remove lens, put shutter on ‘B’, open shutter, place a small bit of masking tape on the film, close shutter, Replace lens and refocus), then do the sequence again.
1600. 1/4. f16
800. 1/2. f16
400. 1s f16.
200. 1s f11
100. 1s f8
Blank frame (remove lens, put shutter on ‘B’, open shutter, place a small bit of masking tape on the film, close shutter, Replace lens and refocus)
1600. 1/4. f16
800. 1/2. f16
400. 1s f16.
200. 1s f11
100. 1s f8
Blank frame (remove lens, put shutter on ‘B’, open shutter, place a small bit of masking tape on the film, close shutter, Replace lens and refocus)
1600. 1/4. f16
800. 1/2. f16
400. 1s f16.
200. 1s f11
100. 1s f8
Blank frame (remove lens, put shutter on ‘B’, open shutter, place a small bit of masking tape on the film, close shutter, Replace lens and refocus)
1600. 1/4. f16
800. 1/2. f16
400. 1s f16.
200. 1s f11
100. 1s f8
Blank frame
Rewind film.
The film was taken out in total darkness and cut on the tape markers, then the bits of tape were removed and discarded, because loose bits of tape floating around during the process can reattach themselves in unwanted areas.
All sections were exposed the same so it didn’t matter in what order I processed them. I loaded one section into the tank and put the other bits in a black film cannister inside two black plasic bags to prevent light from getting to them. I was using ID11 stock solution and had a range of development times that went from 4 minutes to 14 minutes, so I decided to do the longest one first, gradually working towards the shortest. This way it would appear to be getting easier as I went along. All films went into stop bath and rapid fix and were washed for fifteen minutes. I didn’t need to do an archival wash, this was just for a test.
When all sections were processed and dried I laid them out on a sheet of paper and looked at the result. Unfortunately, my strip that was processed for 200 didn’t have a full range of five exposures -I had cut the film in the wrong place!
I will repeat the test and then make a contact sheet. In theory there would be one frame on each strip that will look correct for that particular processing time (this certainly looked to be the case on this first test}. I predicted that the section that was rated at 1600 would have the biggest differences betwen frames and this proved to be the case. This has implications for metering when uprating films, you need to be quite sure you are metering the correct part of the scene.
More to follow soon.