Sorry Ray, I'm not very clear sometimes.
I know the paper was preflashed. I know it received too much exposure, I don't know how much.
I am able to calculate the preflash by using an RH Anlyser Pro. I run test strips for each paper and dev combo and generally do one just below what I can see wet so that when it dries I have a preflash test strip at 1/12 stop intervals. I generally use the exposure compensation setting that corresponds to the first strip with no visible fog when dry. That gives me a factor that can be apllied to any head height or focus setting.
As an example I can measure the white light with my Analyser Pro and then reduce the exposure time by 14 steps (1 and 1/6 stops) with MGWTFB to get my pre-exposure time.
My problem is I'm used to using Galerie not MG and I forgot to put the below lens filter in after measuring the white light, this is something particular to using an Analyser. What it means is that my calibration of all my exposure metering is set up to measure white light but print with filter. I didn't use the No.1 filter that a I should have and so I gave too much exposure to the paper, but I don't know how much.
When printing on the preflashed paper I am able to reduce my main exposure time by about 1 stop (compared to non-preflashed paper) while retaining more detail in the highlights, leaving just small areas of paperbase white. Of course, reducing the main exposure by 1 stop helps immensely in keeping shadows open, remember these are night time scenes. Contrast can then be judged based on what's balck and what isn't, whether those things should or shouldn't be black etc.
Without using a preflash I would have to lower contrast, either through filtration or development control, if I wanted the same level of detail around my highlights and the same black areas. The shadows would then become more murky because they are being printed at a lower grade and receiving about a stop more exposure. The difference is stark.
I know some people use split grade printing to get around this sort of problem but this hasn't been an option for me until very recently because I've preferred Galerie (the only reason I'm investigating MGWT is that Kennedy's won't import Galerie). Of course that requires dodging and buring so the effect is area specific.
In brief highlights determine exposure time, deep shadows determine contrast and I determine them in that order.
I'm not sure what you're really asking but suspect you don't like flashers?
Have a look at my APUG gallery, the night time scenes involve lots of contrast that I don't really want to mush-up by reducing film development time. Preflashing lets me get subtle detail around the light sources themselves, keeps the light sources paperbase white and opens up the shadows considerably. It's a win all round.
As I said, daytime shots don't require it to the same extent because there isn't the same degree of contrast and you're not dealing with failure of the reciprocity law (which tends to increase contrast at long times) and the shadows are lit by open sky.
