Nine Days Later …
Up at 3.30am this morning, to have a go at that photograph!
In the week since the original aborted attempt I came to realise that the optimal time for the shot I am after is in fact about an hour earlier than I initially thought. My original thinking, based on TPE, was that the window of opportunity was between 6 - 7.30am, but having driven by the location at 6am the other day I could see that by then it was all over, I’d need to be all setup before sunrise, and then see how things go (the main light constraint here is complex terrain).
I ended up taking six photos over about an hour or so, with exposures starting at 4min (includes 3 stop reciprocity adjustment) and finishing at 1/2s. As usual, I am not sure if anything will come of it in the end, not only because big reciprocity adjustments are always a bit of a gamble, but the colours at this time of the year are challenging for B&W, and my principal subject might not be sufficiently separated from the background.
That said, the pre-sunrise conditions were particularly fine, and even if nothing worth a print comes from it, it was well worth being out at that time of the day.