On the pictures taken on a family birthday there is a striped brightness pattern presumably due to the lamps’ frequency. Is there any darktable module to remove that?
I remember that i took the pictures in the silent mode of my Nikon Z6 II, that might explain the horizontal striped brightness pattern. Anyway, I would like to remove it.
I am not sure how this problem could be tackled. Can you post a sample file for people to play around with. What was the lighting source?
Moire??
Moire??
More likely banding caused by the combination of LED lights and electronic shutter. I don’t think there is a simple fix to that in post processing.
Most recent cameras let you fine tune the shutter speed in small increments to prevent it in the first place.
You might try to use two instances of exposure module masking the brighter/darker stripes and then use exposure mapping to match the lightness. And maybe do the same with Color calibration to match colors.
But better lern to properly set your camera shutter speed if there is led illumination … that’ a more easy approach
Ya I wasn’t sure from the comment if they “knew” it was the lights or just thought it might be…without seeing what they were talking about I just threw it out there… but likely it is an LED frequency thing…
Presumably it’s this kind of banding:
I don’t know or use dt but this may help on a general knowledge basis:
…this might be worth a look assuming that the stripes are regularly spaced:
Unless @maver can post a sample image or screenshot of the problem we are all guessing blind here what the problem is. The forum is here to help but without an image we can’t be of much help.
Sorry for the long delay. Now I prepared a photo with stripes, faces eraded. According to the metadata, I used the mechanical shutter.
I tried to edit a Fourier transformation but the necessary degree/form of editing eluded me.
Then I looked here which clearly works but which is way above my head!
So, in an editor which provides layers, I would make a mask that exactly matches the stripes and then edit them out of the base image, probably by brightening the darker stripes.
I gave it a shot in the GIMP.
I made a stripe pattern in ImageMagick for the mask. Resized it to match the stripes in the base image then added it as a mask, allowing me to only edit these bits:
I made the base layer visible and edited the masked layer to match the stripe brightnesses in the base layer:
OK in principle but tedious and very hard to match the mask exactly to the original stripes, as can be seen above. A quick check of the original with the GIMP’s Threshold function also revealed that the strip tones are not really constant as also can be seen.
Thank you very much for your help which comprised a lot oft work. Originally, I thought of using a mask and layers with Gimp too, but for 10 to 15 images, this is quite tedious, indeed.
Later today I will go into it again. Thanks.
