Mark Barendt,

I tried with my teenager's pens to draw diagrams like yours to illustrate... and I ended up with something that looked like your very first diagram. So it's a good diagram.

But I don't know if you've focused on this. Every time a toe or shoulder gets involved you lose contrast. There's two curves at work here, film and paper. And flare affects both of their toes. The film curve stretches out so far that no paper can use it all. You only use a small section of the film curve. The paper curve is a distinct S curve, you use all of it, both toe and shoulder.

How much contrast do you want to lose in the highlights? In the highlights you lose contrast from the toe of the paper and flare of the enlarger. If you went with your unusual plan to expose on the shoulder of the film, then you would lose contrast a third time, from the shoulder of the film.

Does that give you flat, muddy highlights. Or delicate high-key tones? I have to guess it's not the dreaded "chalk". So maybe you are onto something. AndreasT knows what it looks like. It's unusual, but it may be exactly what you want.

How much contrast do you want to lose in the shadows? In the shadows, if you expose to "first excellent print" you lose contrast from the toe of the film, flare of the camera and shoulder of the paper. You lose contrast three times in the shadows unless you overexpose enough to put shadows on the straight line of the film. A stop of overexposure may be right.

I like prints I have made where I have shadows on the straight line of the film. At first glance the black under a rock looks pitch black but when you look closely you will see what's under the rock. My preference is to have less compression in the shadows, because it is one place where I can reduce compression.