Whether I use autostretch or a manual GHS my images end up brighter than I like for a final version. Using GHS, I make a large initial stretch, a BP adjustment and then fine stretches to finish. The initial BP adjustment makes a significant difference. As the stretch progresses, there is little to no room for a BP adjustment without clipping.
After I finish working in SiRiL, I bring the image into Photoshop or Gimp for fine tuning. There I find a fair amount of room in levels to adjust the black point and can improve the appearance of the final image (at least to my somewhat naive eye).
On some images, I find it possible to get a satisfying image by bringing the left levels pointer over to the very beginning of the histogram. In many, there is a minuscule, flat line in the left side of the histogram leading up to the point at which the histogram starts up. Generally, to get an image that appears good to me, I need to bring the left-hand slider across the thin line up to the point the histogram starts to climb. I assume that thin line indicates that there is a small amount of data in the flat line region that I am clipping out. I also notice that levels adjustments on the right side of the histogram make visually destructive changes if I intrude into the “flat” line portion to almost any degree.
Am I correct to assume that my dark side levels clipping involves data that is just not noticeable to me, while even minor highlights clipping is very noticeable? If so, is there an acceptable small amount of BP clipping during the stretch process in SiRiL? Or am I better off keeping the clipping to zero and making those adjustments in levels later in the process?
Or, am I just not really understanding what is going on?