Thanks, Kai
Satish, at the end of my last pack, the frog tongue had gotten all crooked and the print wasn't catching it when it left the camera, so the frame was exposed. It was early evening, the light was getting pretty dim, and much of this was in shadow or very low-angle diffuse light. The dial was not exactly at 100% dark but it was very close to it.
Little garage blown out by
limrodrigues, on Flickr
I took a second shot of the same scene, but with the dial at 100% dark. This time I expected the frog tongue to not work, so I held my hand over the front where the print would come out, and I grabbed it immediately to press it against my body and keep it dark. So it's possible without the frog tongue, but it's more of a PITA.
Little garage by
limrodrigues, on Flickr
This was the last shot of that pack. I couldn't adjust the frog tongue until I'd finished the pack, so I knew it wouldn't work properly. I still shielded both the lens and the print when it came out, and the exposure was good, but I got enough solarization that it looks like an inter-dimensional portal was opening up in the sky!
Interdimensional portal by
limrodrigues, on Flickr
And here are two with a working frog tongue, both at probably about 75% dark:
Door by
limrodrigues, on Flickr
Paramount by
limrodrigues, on Flickr