Hi Jonathan,
Barry recommended 4-5 minutes at 21 degrees Celsius. I process always at 20 degrees Celsius. I found that 5.5 minutes at 20 degrees Celsius (with agitation as previously described rather than the relatively minimal agitation many seem to prefer with BTTB developer) was necessary to achieve a negative that would print straight (with a diffusion head) at Grade 3 on VC fibre paper (although I tend to then print at 3.5 - 4 with dodging to achieve a more punchy look with full detail throughout).
I learned a different way to determine optimal film speed, namely to find the exposures that give you printable detail at highlight and shadow end. I used the back of a sheet of hardboard, which I think was an Ansel Adams suggestion, and in effect found zones IX and I using standard development and grade 2 paper. On that basis, I expose FP4+ at 125 ISO(box speed ), and HP5+ at 640 ISO (i.e. 1/2 stop speed gain). By the usual standards, my negs have printable detail at both ends, and appear good in terms of overall density.
I determine film speed and development by the following system:
1. Find a scene with with a good range of tones
2. Using the box speed, meter the darkest area in which you wish to retain shadow detail
3. Move the camera so that you are only photographing this shadow area
4. From the meter's reading close down the aperture by 2 stops or increase the shutter speed by two stops and then expose 6 frames at: the given exposure then +1 stop, +2 stops, -1 stop, -2 stops and -3 stops less than the meter has indicated
5. Process the film
6. Using the frame that was exposed at -3 stops less than the meter indicated (which should be practically clear but will have received lens flair and fogging - i.e a real world maximum black rather than an unexposed piece of film that only has processing fog) and do a test strip to find out what is the minimum exposure to achieve maximum black - Print must be fully dry before assessing this
7. Do another test strip with the first exposure being what you have selected for achieving maximum black minus your dry-down compensation then plus 1 second, 2 seconds, etc
8. The time that achieves full black inclusive of compensation for dry-down is you minimum exposure to achieve maximum black for all future printing sessions - print must be fully dry before assessing
9 You now know the minimum time to achieve full black inclusive of exposure reduction to accommodate dry-down
10. Using this minimum exposure to achieve maximum black exposure time, expose all of the other test frames.
11. The test print that has good shadow detail indicates which exposure will render good shadow detail and achieve maximum black and provides you with your personal EI for the tested film/developer combination
12 If the negative exposed at the meter reading gives good shadows, your EI is (when metering shadows where you wish to retain good detail) the box speed (i.e. for 400 film you need to set your meter at 400)
13. If the negative exposed at +1 stop more than the meter reading gives good shadows, your EI is (when metering shadows where you wish to retain good detail) 1/2 the box speed (i.e. for 400 film you need to set your meter at 200)
14. If the negative exposed at +2 stops more than the meter reading gives good shadows, you EI is (when metering shadows where you wish to retain good detail) 1/4 box speed (i.e. for 400 film you need to set your meter at 100)
15. If the negative exposed at -1 stop less than the meter reading gives good shadows, you EI is (when metering shadows where you wish to retain good detail) double the box speed (i.e. for 400 film you need to set your meter at 800)
15. If the negative exposed at -2 stop less than the meter reading gives good shadows, you EI is (when metering shadows where you wish to retain good detail) 4x the box speed (i.e. for 400 film you need to set your meter at 1600)
Back in the real world, all you need to do in future is meter the shadows that you wish to retain good detail with meter set at your EI and then stop down the aperture 2 stops or increase the shutter speed by 2 stops. In the darkroom start your first test print with the minimum exposure to achieve maximum black (inclusive of dry-down compensation) and go from there.
Your filter suggestion is excellent, too. Because I like things simple, I tend to use a yellow filter only, and only for sunny landscapes or portraits in good light - I should think more often of using filters in other situations.
The Wratten 12 (minus blue) is a yellow filter with a very precise effect on a particular wavelength quite different from other yellow filters.
I still have the problem of existing negatives though.
On thing that you can try with existing negatives is to Selenium tone them. This gives both an increase in density and an effective increase in contrast.
and really want to control the print. I like the idea of increasing micro-contrast. I'll give Dokumol a try. Wish I could do it with raw chemicals, though.
I prefer Dokumol to all other developers. However, I have the following formula for a high contrast developer in my note book if you would prefer to mix your own:
Water 750 ml
metol 2 g
Sodium Sulfite anhyd 40 g
hydroquinone 12 g
Sodium Carbonate 80 g
Potassium Bromide 2 g
Distilled Water to 1 L
Also, Michael Maunder from Speedibrews advised me many moons ago that adding a little Caustic Soda (be careful though!) to any developer would increase micro-contrast. However, being satisfied with Dokumol, I never got round to testing this.
Bests,
David
www.dsallen.de