I have night shots with a star sky and dark ground. Now, I see that I have some very prominent hot pixels in the bottom area. But I cannot limit the hot pixels module to only work in a certain part of the image. Instead, I only can apply it globally resulting in stars being accidentally marked as hot pixels and removed.
I know, that I can post-process the image in e.g. GIMP later, but this is not the way I would like to work since it is very time consuming. I would like to apply the hot pixels module parts of the image. Is it possible? There is masking option but it only has blend setup which I assume is not right in this case?
It looks as if that module has masks disabled permanently. A hint for that might also be the absence of parametric masking options in the screen shot…
@pehar: have you actually been able to use a drawn mask with the “hot pixel” module?
CTRL-mouse scroll normally changes opacity of the hovered shape. But indeed, this seems not to work for this module.
I have no suitable image available so I can’t test with a real example. But I see that no mask is visualized (yellow) when the corresponding button in the module header is clicked. In fact, it seems that this behavior applies to all modules very early in the pixelpipe. Hot pixels can’t be moved in the pixelpipe (CTRL-SHIFT-drag) so masking indeed seem impossible.
Never realized this behavior before, you keep learning even after more than 10 years of using darktable …
This is a drawn mask for Hot pixels, opacity can be modified by CTRL-mouse-scroll, visualized by the number in the faded in overlay.
In the screenshot the visualization of the mask is activated (button in module header selected, image shown in grayscale), opacity is at 100 %, but i can’t see any influence from the shape.
OK, I understand, I relied on the (yellow) visualization of the mask beeing not visible here. I have no suitable sample available to check if this module working correctly with a dawn mask. @stakaz could you please check with your real test object ?
The possibility of visualizing a mask by the yellow overlay is coupled with the availability of mask refinements (feathering, blurring, etc.). The “display mask” button in the “blend mask” section of the module is also only available in this case.
For all modules before “demosaic”, including “hot pixels”, the mask refinement is not possible for understandable reasons.
I tried to find the corresponding code, but my knowledge of C/C++ is unfortunately too poor.
What makes the situation irritating is the fact that the modules always have an additional “display mask” button in the module header, even if no yellow overlay can be displayed due to the position of the module in the pixel pipe for the reason mentioned above.
Yes, I will do so. But currently I’m not sure what is better:
Add a note to the manual and leave darktable as it is
or
Modify the visibility or selectability of the “display mask” button in the modules header for modules before “demosaic” and leave the manual in it’s current state.
