Consumer films of the past (I exclude 2 special films from Kodak and Ilford) had as base material TAC, maybe even dyed a bit.
Non-consumer films since many yeas got a base from PET which is not dyed and moreover already as such has higher transmission for light. This difference in base material may show when handling such film in daylightl. Such handling did not take place at non-consumer uses, but it does take place in loading a camera with type 135 film.
Here light may enter the leader and be transmitted up into the part still in the cassette. This is what "Light-Piping" in our context refers to.
Since about 20 years now such films (mostly made by Agfa) are offered to consumers and has this effect been described.
Yes, my dear teacher.
Indeed, this is a strange and unfamiliar brand in every way.
- There was an Egyptian merchant who specialized in the trade of photographic supplies. This man found a large stock of Svema films - ISO 25, and of course the young men were very happy about this amazing discovery, as if it was one of the mummies of the builders of the pyramids. Because the price of the roll was only a dollar and a quarter
- There were several problems with this huge amount of films.
- It is by nature a strange emulsion, it does not have a protective layer, and when you load the film with a camera, you are surprised that you find that your fingers have mysterious black traces, especially if the weather is hot.
- When you download the film in the development tank, the same thing happens, and you should not be surprised when you find that some pictures have been deeply scratched or that some parts of some pictures are completely erased, because that black substance that stuck to my fingers is actually silver halides (emulsion ) on which the underlying image is formed.
- Many young men were surprised while loading the film into the camera that the film cassette was not tightly closed, and when they were downloading the film, unfortunately, the cassette was opened from the top... and the film was lost.
- And there was an incident that happened before my eyes in front of the Great Pyramid, where a young man had loaded a roll in his house and came to the Pyramids and photographed the roll and finished and removed it from the camera and loaded another roll in front of the Great Pyramid. When we developed the roller in one tank, the results came out that the first roller had good pictures and the second roller did not produce any pictures,, and I think that the reason was that the roller was loaded in broad daylight and in front of the strong sun.
- I had not used this roller at the time, but I heard all these problems, and based on all that, I became terribly famous for using this brand so that I knew which one of us would win over the other,
So I loaded the roll into the F4 camera in the dark room and took it to the gardens and orchards, and I photographed this roll, and I did not remove it from the camera on the street, but I waited until I came home and removed the roll and loaded it into the development tank at the same moment In the dark room.
- After development, it became clear to me that this emulsion needs to be washed off with the final washing solution. I actually soaked it in a stapler solution for five minutes, and it ended well and quietly.
And these are the results.
