How does it feel to replicate an 18th century technology — its borderline feeling stupid and exhilarated. Stupid because, well, the technique was used over a century ago, exhilarated because of the joy of learning something from first principles. We – Priyanka, Khusboo, Yashi, Puneet, Geeta and I – successfully made and operated a pinhole camera resulting in a photograph that was developed and fixed at home. Without overloading with the how and whys, this was the final outcome. Yes, its a negative image because we directly exposed the photopaper. It was inverted in lightroom to get the positive.
Now there are numerous websites talking about what a pin hole camera is. Wikipedia article on pinhole being a good start. In short its just a light tight box, where on one side there is a ‘pinhole’ and on the other side is a negative or photo paper. We directly used photo paper as a negative as to use a real negative, develop it, fix it and to make a print from it required more equipment that we were ready for. In all we used,
To make the pinhole camera
- A cardboard box
- Black tape to make it lightproof
- Aluminum foil
- A needle
- A cutter or knife
To make a print
- Photo Paper
- Fixer (Hypo)
- Plastic Trays
Getting Photo Paper, Developer and Fixer in Bangalore itself was a challenge, but finally got it Foto Circle near Majestic (Ph: 080 22874356, Mr. Jayesh). We actually made two, one was made in the night, but did not yield well exposed prints (even after 30 minutes of exposure). The other one shown below was used to expose an outside scene around 5pm in the evening.
There were lot of thing I was not sure in the whole process. Learned some basics in the process.
- Size of the Pinhole: I had read that it should not be too big which will cause blurring and should not be too small as it would also lead to blurring due to diffraction. I think the optimal size is somewhere around 0.2-0.5mm diameter, although there are more refined calculations available online.
- Focal Length: The focal length of the camera we built is about 125mm as the paper is kept at about that distance from the hole, however this is for a 125mm negative (or the size of the paper on one dimension). Thus the 35mm equivalent focal length is about 35mm itself (35mm x 125 / 125). Meaning that this camera is good for semi-wide angle images.
- Aperture: The width of the hole in our camera is about 0.5mm, thus the fnumber is about 125mm/0.5mm = f/250
- ISO of the paper: Now, usually people will use negatives in pinhole camera but we used photo paper directly. It took us about 3 minutes to expose a 5pm cloudy scene. The same scene was rightly exposed with the DSLR using 35mm, f/3.5, 100ISO, 1/120 sec. Mapping to the numbers of our camera f/3.5 to f/250 is about -12 stops, 1/120 sec to 3 minutes is about +14 stops, so most likely the ISO of the paper is 100 with – 2stops or about 25ISO. This is just a wild guess, but I think good enough to measure the right time of exposure for our pinhole camera by using the DSLR to get the times.
- Developing/Fixing: I used the measurement mentioned on the pack, and using normal dilution of the developer it took about 20 sec to develop and 10 sec to fix, followed by washing it for 15 mins.
The next step would be how to make the photo paper, developer and the fixer at home or make it from first principles. Ultimately I want to try tintype and ambrotype photography for which I will also need to make a large format lens based camera at home.