High contrast metol/ascorbic acid developer for dry plates... "C-19"?

[ProfessorC1983]

I'm trying to maximize density range with homemade dry plates (plain silver emulsion) for alt-process work. I decided to whip up a modified version of D-19 using ascorbic acid instead of HQ, which I've been rather cheekily calling C-19. My formula is:

750ml hot water
2g metol (pinch of sulfite first)
8g ascorbic acid
100g sodium sulfite
50g sodium carbonate
2g potassium bromide
water to 1L

This is working well so far and gets real close to my DR target of 2.1, but N development still takes 12-15min (my emulsion is quite thick!) and doesn't seem to leave a lot of room for expansion. I'd like to refine a bit further. I wasn't totally sure about the correct M-C ratio... many recipes have it at 1:4 just like for HQ, but others have 1:6 or more.

I may also leave out the bromide entirely next time, as I don't have much of a fog issue with my current emulsion recipe.

Any other ideas for maximizing contrast with M-C?

 

[Nodda Duma]

If I get my hands on some ascorbic acid I’ll check it out.

Other tricks to try: You can increase contrast / maximize density range by second ripening longer when you are making the emulsion (assuming sulfur sensitization). Speed will increase but so will contrast and max density. I don’t know what your current max density is, but coat a sample plate every 10-15 minutes additional ripening and you can generate a Dmax vs time plot.

You can also increase coating thickness