05-02-2020 04:26 AM - edited 05-02-2020 04:51 AM
RawTherapee can show which channel that is clipping or where all channels are clipping at the same level. To me DPP4 seems to only show a highlight alert when all channels are clipping at the same level. I haven't found any documentation in the DDP4 manual.
If you want to see where one or all channels are clipping, use RawTherapee. For all channels, RawTherapee or DPP4.
About the raw file you have a raw histogram in RawTherapee you can activate. That will show you that you could have collected more light with your camera (without clipping the highlights) to get less visible noise in the shadows. The button is beside the histogram and looks like bayer pattern. RawTherapee and not DPP4 either will be able to show where in the picture the raw file is clipping the highlights. They just show where the generated file will be clipping the highlights.
The last screenshot is from Hraw. Normally I use Hraw to analyze dynamic range in raw files but there is also a more simple feature. When downloading Hraw for Windows there are three files included. Dcraw, Hraw and Revelator. Drag and drop a CR2 file into Revelator and you will see how much highlights that are clipped. A tif file will also be generated and will show where and in which channel that the raw file is clipping the highlights. Another raw converter, darktable, can also show where the raw file is clipping the highlights but the white balance module in darktable needs to be turned off then.
So, what is the point to know where the raw file is clipping the highlights? Well, here is an example with three screenshots. The first shows Hraw and the generated tif file. The colours show you the highlight clipping. Green is green channel. Yellow is green and red channels. White is green, blue and red.
In darktable you will see the same thing but in a different way with red, blue and green dots. White balance is turned off and that is why the overall picture seems green.
In RawTherapee it is possible to reconstruct clipping highlights if there is still one channel left that isn't clipping. Check the last screenshot that is an animated GIF file. RawTherapee has reconstruced the area where green channel is clipping by using red and blue channel. RawTherapee has also reconstruced the area where green and red channels are clipping by using the blue channel, but RawTherapee has failed to reconstruct the area where all three channels are clipping the highlights.
05-02-2020 11:22 AM
Well now, I certainly never imagined getting such a good lesson on Rawtherapee in this forum. Many thanks for that. The lesson went well beyond answering my original question. As you suggest, I also have found the documentation for DPP a bit lacking but I am inclined to accept the explanation that what I noticed is attributable to the difference between some channels being clipped and all channels being clipped.
With respect to HRAW, the only thing I could find is this. It sort of looks like what you are referring to. However, I don't see anything that looks like a Windows binary. Also, no documentation. Is that what you reference? If so, might you know where to find Windows binary? Of course some documentation (maybe it has help) is likely needed.
05-02-2020 11:47 AM