When to apply noise reduction?

[kdash1228]

When editing RAW images, when is it the best time to apply noise reduction? Should I apply it before or after I apply my color edit changes in Lightroom? Should I apply it before or after I edit the image in Photoshop?

I can use the following noise reduction tools: Lightroom denoise or Topaz denoise

When I am editing, I apply edits in Lightroom then apply more edits in Photoshop.

[Ian Lyons]

I've copied below from the AI Remove tool thread.

The recommended order for applying edits is:

1. Denoise 
2. Heal (includes Generative AI Remove)
3. Crop (includes traditional Cropping, Lens Correction, Transform, or any operation changing the geometry of the image)
4. Global Edits
5. AI Selective edits (Sky, Person, etc)
   
   If you deviate from above, you may see the removed object remain as a ghost image. If this occurs, you will have to use Update AI Settings, which can be found under the Develop module 'Settings' menu.

[AxelMatt]

Normally the noise reduction is one of the last steps that has been done on editing. Because some editings can be increased the noise.

Which denoising tool you're using can be decide for yourself. It depends a little bit of your hardware. The Lightroom denoising needs a potential hardware. In my expirience Topaz is faster and the result is slightly better.

[John Waller]

Interesting how different people advocate different workflows.

Andrew S Gibson (Mastering Lightroom) suggests using Denoise as a first step.

How to Use Denoise in Lightroom Classic | Mastering Lightroom (mastering-lightroom.com)

He says:

• It’s a good idea to apply Denoise early in your workflow, before using Healing or AI masking. AI driven tools like Content-Aware Remove and AI masking can be affected by noise, and work best with a clean starting point.

• If you apply Denoise to a photo that already has an AI mask or Content-Aware Remove settings, then Lightroom recalculates and updates those spots and masks. That adds to the processing time, and you also need to check the result to make sure everything is okay. This increases the work you have to do, which is why Adobe recommends that you run Denoise first.

Adobe also suggest applying Denoise early, before healing and masking.

Denoise Demystified | Adobe Blog

"Order matters. I recommend applying Denoise early in the workflow, before healing and masking. AI-driven, image-based features such as Content-Aware Remove and Select Subject can be affected by noise, so it’s best to use those features on a clean starting point. If you do run Denoise on an image that already has Content-Aware Remove settings or AI masks, Denoise will automatically update those spots and masks. This is handy, but be aware that the content of those spots and masks may change unexpectedly, so it’s best to review the results carefully."

I don't think there's any hard and fast right or wrong here. Just what works best for the image.