Long exposures with the Altissa
I had a lot of fun shooting my grandfather's Altissa Box D camera and processing the black and white film, so I wanted to experiment with something new: daytime long exposures.
I planned to try 1-2 minute exposures. With such long exposures, the clouds appear as streaks, moving water becomes smooth, and people look like ghosts, or simply disappear.
The neutral density filters
A strong ND filter is needed, to reduce the amount of light that hits the film by a factor of around 1000. But this vintage camera was not designed to accept filters - there is no simple way to directly attach a filter to the lens. So, the front plate of the camera had to be modified...
To avoid damaging the original camera, I bought a second one, identical, for spare parts, and I used its front plate. I found a 52 mm filter adapter ring in my accessories bag - perfect! This adapter ring was attached to the front plate and secured around the camera's lens, ready to receive the ND filter.
The shutter mechanism was modified and made bi-stable: in the Bulb position, the shutter remains open until the operator manually closes it. This was done by simply removing the shutter lever return spring.
The first problem appeared when I measured my Chinese ND1000 filter's strength using a digital camera - it is not a ND1000. It is one stop faster (ND500), letting in twice the light amount it is supposed to. So I had to stack a second filter, an ND2, on top of it.
Choosing a film
The film choice was not easy - as much as I like B/W photos, color can add an extra dimension to an image. I eventually decided to use a Kodak Portra 160 film, and to process it myself! I had never processed a color film before, but how hard could it be?
The 12 frames of the film were shot on a weekend afternoon. The ambient light was measured with a digital camera, multiplying the resulting exposure by the ND factor. I have an app on my phone that helps with this operation. Then, the total exposure time must be compensated for film reciprocity failure. This means that a film is becoming less and less sensitive the longer it is exposed, and the exposure time must be increased. The tables below indicate the adjustments needed by Kodak Portra and Ektar films.
The C-41 color process
I bought the Tetenal C-41 color chemistry kit and did some research online. The process is less difficult than it appears to be, but it requires precision and attention. The developer, the stopper, the bleach-fix and the stabilizer were measured, mixed and brought to 38°C in a water bath.
Once the process is completed, the moment of truth arrives: opening the developing tank and examining the film! It's quite satisfying to see that the photos taken days ago are now safely developed.
The result
The film was digitized with a digital camera and a macro lens. Converting the color negative to positive is not an easy task - because the film base is orange, it leaves a strong color cast that needs to be neutralized.
Looking at the resulting images, a problem became apparent: the frames were not uniformly exposed - there were patterns of lighter and darker areas on the film. Since the shape of the darker areas looked suspiciously like the profile of the film transport rollers inside the camera, this could only mean that the camera had a light leak. To find the exact spot where the stray light was entering the camera, I placed a LED lamp inside, and closed the camera. I took it to a completely dark room, and once the eyes get adapted to the darkness, the source of the problem became apparent - light from the lamp escaped from the camera through some seams! These places were then covered with black sticky tape.
Here are a few photos that I managed to salvage:
They look kind of "vintage", don't they?
More long exposures on Kodak Ektar
After this first experiment, I shot a second film, this time with the camera properly isolated against light leaks. The two-minute exposures that I had done before showed a total absence of car light streaks, even if dozens of cars passed by - so this time I settled on blue hour photos, with shorter 20-30 second exposures. This time, a Kodak Ektar 100 film was used. It has a different look compared to the Portra - the colors are more vivid.
...and a rainbow:
