Re: Dynamic Range and Strange Behaviour
Posted: January 13th, 2012, 11:06 pm
Couman,
One of the attachments in my original post is a crop of the image in question. In the crop (I know it's small, but I was limited to 400 X 400 pixels) there is a piling which consists of a red light on top of a white pole which, in turn is atop a structure, which in the crop looks to be a light brown/grey with black edges. That light brown/grey with black edges area is supposed to be all black, at least that is what it was when I opened it in PWP (measured 0,0,0). The only thing I did in PWP was move the right slider, in Levels and Colour, of the Dynamic Range from 98.4 to 100% (the range was initially 31.8 to 98.4 but I did not move the 31.8). When I pressed OK and generated the new image, the previously black area was now the lighter brownish colour with the black edges as in the cropped image. Naively thinking that 0,0,0 black shouldn't change so drastically to a brown/grey by merely shifting the highlight end 1.6%, I sought an explanation here. I must admit I may have clouded the issue by asking questions about more than one specific topic and by also attaching the other image, but I did that to give the viewer a bit of an idea of how big the piling was in the full image (however, I didn't realize it would be so small to see the content well). As Jonathan has pointed out, the area that I measured at 0,0,0 (and which eventually turned to brown/grey) was small enough to be less than the 0.01% which PWP ignores in it's DR assessment. I did not make any changes to the Brightness Curve so that has no bearing on what occurred.
Den,
Right, I now understand what you wanted the RAW file for. Yes, when I prepared the two attachments in my original post, I converted them from AdobeRGB to sRGB.
Marv
One of the attachments in my original post is a crop of the image in question. In the crop (I know it's small, but I was limited to 400 X 400 pixels) there is a piling which consists of a red light on top of a white pole which, in turn is atop a structure, which in the crop looks to be a light brown/grey with black edges. That light brown/grey with black edges area is supposed to be all black, at least that is what it was when I opened it in PWP (measured 0,0,0). The only thing I did in PWP was move the right slider, in Levels and Colour, of the Dynamic Range from 98.4 to 100% (the range was initially 31.8 to 98.4 but I did not move the 31.8). When I pressed OK and generated the new image, the previously black area was now the lighter brownish colour with the black edges as in the cropped image. Naively thinking that 0,0,0 black shouldn't change so drastically to a brown/grey by merely shifting the highlight end 1.6%, I sought an explanation here. I must admit I may have clouded the issue by asking questions about more than one specific topic and by also attaching the other image, but I did that to give the viewer a bit of an idea of how big the piling was in the full image (however, I didn't realize it would be so small to see the content well). As Jonathan has pointed out, the area that I measured at 0,0,0 (and which eventually turned to brown/grey) was small enough to be less than the 0.01% which PWP ignores in it's DR assessment. I did not make any changes to the Brightness Curve so that has no bearing on what occurred.
Den,
Right, I now understand what you wanted the RAW file for. Yes, when I prepared the two attachments in my original post, I converted them from AdobeRGB to sRGB.
Marv