This is an experimental exercise that I have done once before. This time I tried two different films 200 and 800 Kodak 135mm film in the C-41 process.
The development was over 6 hours standing in tank with slightly diluted C-41 developer. Only agitated once in the beginning. I did dilute because the JOBO tanks swallow lots of liquid when standing, and it was the last of the chemistry. The rest of the process is made on the JOBO 1000 as recommended.
This renders an extremely dense negative, and it is almost completely black. When put on my rig for digitalization with a Nikon 610 camera, it is possible to see the image through the back projection in the camera. I used between 1/3 to 4 second exposure and the 50mm lens with close up rings stepped down to f4 on 400 ISO.
On some of the images I used a home made lens modifier. All images are shot In parks/woods near Söderköping, Sweden.
The extremely dense negative makes it hard to digitize. The perforation of the film, where light passes through maybe more than 10 times easily, gives a high amount of flare. So I also tried a narrow frame that cut out the image border and the perforation. I do like some of the effect but I feel that the color information is lost to a big extent. Next time I will cut the development time by half, or even more to see what happens.