Issue with noise reduction luminance curve ?


I’m an astrophotographer using Rawtherapee for some time now, and i like it a lot.
A tool I use a lot is the noise reduction luminance curve, which allows me to deal with noisy backgrounds without altering at all crispy bright parts.

However, I just noticed that there is a difference ( sometimes quite strong ) between the viewed image and the saved image ! The saved image often seems noisier…
Is this an intended feature, is there something i missed ?


Hi @Roch


Are you viewing the noise reduction at 100% zoom in RT?

What OS? What RT version?

We need more details so we can help you

Hi, and thanks for the reply :slight_smile:
I’m on Windows 10
I was using Rawtherapee 5.3, and then I downloaded latest version ( 5.7 ) to see if the problem was fixed ; it is not.

I’m viewing the image at 100%.

To clarify my point, here is a printscreen of the editor during the processing of my current work, and then the processed image. As you can see, the texture of the background is totally different ( better to see it at 100% but even on small size it’s noticable )

I tried to save in another format or compression as well.

I wonder if there is a conflict between the exposition curve and the noise reduction curve, since it’s the only other thing I touched on the software concerning this particular image.