HIPPOLYTE BAYARD direct positive process

[brucej]

Has anybody tired this ?

The direct positive process involved exposing silver chloride paper to light, which turned the paper completely black.
It was then soaked in potassium iodide before being exposed in a camera.

After the exposure, it was washed in a bath of (Sodium thiosulfate) hyposulfite of soda and dried.

The resulting image was a unique photograph that could not be reproduced.

Due to the paper's poor light sensitivity, an exposure of approximately twelve minutes was required. Using this method of photography, still subject matter, such as buildings, were favored. When used for photographing people, sitters were told to close their eyes so as to eliminate the eerie, "dead" quality produced due to blinking and moving one's eyes during such a long exposure.

 

[phritz phantom]

sounds interesting.
is the paper still wet (from the iodide) during exposure?

 

[Ian Grant]

Kodak manufactured a direct copying film that worked in a similar way, and I think EFKE still make a direct positive paper which is sold by Freesyle. They still need developing though.

Ian

 

[brucej]

sounds interesting.
is the paper still wet (from the iodide) during exposure?

sorry I dont have have that info
do you think it should be wet ?

 

[phritz phantom]

sorry I dont have have that info
do you think it should be wet ?

i have no idea... this is the first time, i've heard about that process.
if you'd soak it in iodine, it gets wet, which would be rather impractical to have inside the camera. but i don't know if the process allows a intermediate drying.

 

[removed account4]

Kodak manufactured a direct copying film that worked in a similar way, and I think EFKE still make a direct positive paper which is sold by Freesyle. They still need developing though.

Ian

"professional duplicating film" was a single step ( negative to negative or positive to positive ) film that kodak sold but stopped making.
photowarehouse sells the same thing .. it is very slow, like azo paper,
and requires a floodlight to expose (i have used a 300W bulb) it would be between 7 and 10 stops slower than conventional photo paper, rated somewhere
between asa 6 and 25 ... and it is processed in paper developer ...

some folks have had very good results shooting the efke paper.
on the large format forum there are a handful of recent posts that look very nice.

 

[GCyberfish]

I tried this with standard photo paper and got ... intresting results but nothing useable for
photographic purposes:

I may have to experiment with the time of preexposure and the type of
Developer. Maybe a ...surface -developer?(<-don´t know the word for it) would work better than RODINAL.
TALBOT described the Iodide-method in combination with his calotype
process.

I hope you can understand my english

 

[c6h6o3]

So I guess they were dry.

The paper has to be exposed wet. The Dead Link Removed only works in the presence of light, oxygen and water.

 

[cliveh]

The paper has to be exposed wet. The Dead Link Removed only works in the presence of light, oxygen and water.

Like most halogen based processes they work faster when wet, but will still work when dry, but at a slower rate.