It's the better midtones that drew me to older, single coated lenses, but then you have to protect the highlights better in developing. That single coating on those old lenses not as effective in highlight protection. Don't you run the risk of blowing the highlights with stand because of the potential of overdevelopment?
So a couple of reference points. First, semistand/EMA are done with much higher dilution (i.e. weaker) developer which is inherently less active. Secondly, you're agitating almost not at all.
Why does this matter? The shadows develop quite slowly. That's why you want to leave the film in solution for a looooong time - to get full shadow speed. But highlights develop rapidly and then the developer there exhausts more-or-less immediately. That means semistand/EMA will inherently protect highlights. They won't overdevelop because - without agitation - they stop developing very quickly.
But this brings new problems to be conquered.
First, when you don't agitate very much, development byproducts begin to build up on the film and can lead to streaks - the dreaded "bromide drag". Hence, my recommendations in the prior post about taking great care with film suspension above the bottom of the tank and maintaining minimal contact with the suspension system.
Secondly, you have to find the right triplet of developer, dilution, and time to optimize for full shadow development completion and reigning in overly aggressive highlight development. Time gives you the shadows and the mid tone contrast expansion, and the dilution keeps the highlights in bounds. The other consideration is that if you get too dilute, you can make it up - up to a point - with longer times, but you may be increasing acutance beyond what is appropriate for smaller formats and thus really making the grain show up.
Finally, the more you dilute, the more developer volume you need to use to ensure that when you do agitate, there's enough active developer present to do the job.
I have generally found that Pyrocat-HD at 1.5:1:250 for 30min with one starting agitation for 1 min and another at 16min to be a good starting point for normal SBRs. I've also gotten good results at 1.5:1:300 for 40-45 min. D-23 mixed 1+9 with 0.5 g/l sodium hydroxide also works well for 30 min semistand.
Some examples ...
I mentioned this image upthread:
There was bright, direct sunlight hitting the bark from scene left, but the overall scene had a few dark areas but really boring local contrast in the mid tones. The really interesting textures at the center of the image had very little tonal separation. So I used Pyrocat-HD diluted 1.5:1:300 and did EMA for an hour. This gave me great acuity, razor sharp edge effects, and really nice mid tone separation. Most importantly it held the highlights where the sun was hitting the subject directly. The negative is dense, but certainly not unprintable. In fairness, this was 2x3 Efke PL100M sheet film that is known to be a good semistand/EMA candidate.
My experience is the MQ developers don't work as well for this. So I avoid this with D-76, DK-50 and the like. But it can be made to work as well. For example:
This Fompan 200 4x5 semistand processed in DK-50 1+3 for and hour. Again the negative is dense, but quite printable. I find the overall contrast to be a bit of overkill and the highlights edging right up to being blocked. In retrospect, I should have used less time and/or greater dilution to keep the contrast dialed down a little. That said, the print (these are both print scans) show great edge effects and mid tone contrast.
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