copy color correction from one picture to another in siril

Mockus · July 27, 2020, 6:05pm

Is it possible to copy the color calibration from one picture to another in siril?

Background: I want to create a photo of Neowise with a stacked starfield and a different stack for the comet. Those two should be blended together in a later stage. For the starfield I could use photometric color calibration. But for the comet this is not possible, because of the trailing stars. So I would like to copy the photometric color calibration from the star field photo to the other.
From the he photometric color calibration I get those values:

19:59:03: 0 stars excluded from the calculation19:59:03: Color calibration factors:
19:59:03: K0: 0.805
19:59:03: K1: 0.611
19:59:03: K2: 1.000
19:59:03: Background reference:
19:59:04: B0: 3.93619e-03
19:59:04: B1: 4.24014e-03
19:59:05: B2: 5.50136e-03

Can I use those?

lock042 · July 27, 2020, 6:29pm

Hello, answer is easy. No. The parameters are not the same. So for now, we can’t.

vinvin · July 27, 2020, 6:31pm

Why are they not the same?

lock042 · July 27, 2020, 7:12pm

Not same algorithm. That is not just multipliers.

I know it is a pain, but for the manual part I tried to reproduce PI behavior in fact.

vinvin · July 27, 2020, 8:00pm

I don’t get it. If you have input images that you stack, once aligned on the comet and once aligned on the stars, why wouldn’t you be able to apply the parameters of the colour correction obtained from the second to the first?
What do you mean ‘not same algorithm’?

Mockus · July 28, 2020, 8:26am

If I understand it correctly: The parameters of the photometric color correction can not be applied to the picture currently. If you would use the color calibration with some parameters it would be possible.

@lock042 Should I open a feature request for that? Or is it already on the list?

lock042 · July 28, 2020, 6:21pm

Not really. I already tried to do something easy for user, but in fact it is not easy.
The white balance is not only done with the W parameters computed by photometry. You also have the background parameters that are used as well. These parameters can be very different between images. So, this is why I say that W parameters are not enough.