eek!
Didn't mean to cause a stir!
I certainly wasn't targeting anyone in particular and I apologise if I came across dismissive of anyone. I'm was just trying to look out for the newbies!
I don't trust histograms because of this; big black stacking artifacts (as is the case here at the bottom of the image) skewing your histogram. Just like you Jase, I always load the image into a processing application. When I suspect clipping, I always sample the darker areas for R G B values with a dropper. Doing this the image looked ok to me at the time and nowhere could I see perfectly black pixels or distinct colored tinges.
Looking at the histograms, cropping the stacking artifacts out, things look a bit better. Though, I have to admit, still not perfect for the green and blue channels.
However, to illustrate the distribution of (possibly!) clipping pixels in the green and blue channels (assuming we are now satisfied red is not a problem), I've created an image showing where pixels are (possibly) clipping the green and blue channels (e.g. they are both 0, with only red being positive - done by removing the red channel, then doing a threshold of all but the 1st value in the histogram).
http://www.startools.org/download/clipping.png
Not too shocking now I would say. Seeing as their distribution is quite sparse (e.g. there are non-clipping pixels adjacent to most of the 'clipping' pixels. I would say that a good deal of these pixels are 0 because they are just properly 0 or fractional - not negative. Indeed, if I use a morphological dilate operation, virtually none remain (e.g. proof that they are very local 'dips' in the signal and bounce back up to connect with a non-0 R, non-0 G, non-0 B neighbouring pixel). Indeed in a 16-bit resolution these pixels could well be non-0.
In this synthesized image, I would be worried if there were a clear boundary beyond which large black areas were visible, however there are always non-black pixels peeking through here.
To make a long story short, I still believe the full dynamic range was used in this image, even though there are pixels that have either red, green or blue set to 0. I don't believe it is to the detriment of the image and I don't believe any detail is lost. Now, would I have liked to have seen some background level? Probably. But I still don't think there is a case to call the image 'clipped'.
Again, my sincere apologies if I offended anyone - happy to take any further conversation private.
Cheers,