That sounds very intereesting David, but while I think I follow the method, I wonder if you could expand it a bit more to make it clear for a dimwit like me?
The testing goes like this:
Take three different negatives
Stage One
Put first negative in and do a test strip to ascertain minimum exposure at #1 to achieve
a trace of tone in the brightest highlights.
Once you have identified the time (need to do this when the test strip is fully dry if using fibre-based paper) do a second test strip to identify the minimum time at #5 to achieve a black in the darkest shadow are (i.e. clear or virtually clear part of the negative).
Note down the two times.
Stage Two
Place second negative in enlarger and expose using the two times for #1 and #5.
Does the highlight have a trace of tone and does the black look black? - if yes proceed to Stage Three / If not repeat Stage One with the second negative and note down the two new times for #1 and #5.
Stage Three
Place third negative in and use either the times for #1 and #5 identified in the Stage One test. Does the highlight have a trace of tone and does the black look black? - if yes proceed to Stage Four / If not repeat Stage One with the second negative and note down the two new times for #1 and #5.
Stage Four
You may have found that the times for #1 and #5 were the same for all three negatives (usually very unlikely) or that you have a small range of times. If this is the case, take the average between them and write down the time you have identified for #1 and #5.
Thereafter,
For every subsequent print you always start with the #1 time that you have identified and follow this with the #5 time that you have identified. You then do a traditional test strip at #3 to identify final exposure which will be a combination of the #1 time, the #5 time and the #3 time.
I just want to stress that this is essentially a 'quick and dirty' version of split grade printing and was mainly used for printing to 'commercial' standards and not 'fine art' standards. Nevertheless, I find that it works great when printing other people's negatives.
The key to the whole system is choosing an area that should be black in the print (as the subsequent #3 exposure will add to the density) and highlight #1 exposure should give just a trace / slight but visible difference to paper base for the brightest part of the image where you want a tone (as the subsequent #3 exposure will add to the density).
Hope that explains the system better for you pdeeh.
Bests,
David.
www.dsallen.de