[raymo]

Thanks everyone; Acarleton, I live on the edge of a smallish town, so LP is not too bad, although for 253 I am looking right across the town, so I cop what LP there is. I have four streetlights within 50 metres of my
imaging site. I rarely do anything much outside of DSS. I have PS but
rarely do any processing with it. The only thing that I do to try and
keep the sky dark is in DSS. After the final pic is produced by DSS
I use the RGB/luminance/ saturation window to produce my final pic.
You will see low, medium, and high luminance sliders. One low
slider is set at 80% by default. When otherwise happy with your pic you can move that slider further to the right , which will darken the sky
somewhat. You will see a medium slider which from memory is set at 33%. Careful minor movements of that one will also darken the sky, but at the price of a loss of medium level detail, such as the wispy edges of
a nebula. I'm a digital newbie; these are just tips that I've been given.
The only real down side is that all DSS sliders are very difficult to move in small steps. Happy processing.
I don't take separate darks; I just use noise reduction.
raymo