Noise reduction & smoothing for part of the frame ?
I've been grading some film scans and playing around with noise reduction as to reduce grain on certain film stocks which tend to have more grain.
Depending on the film stock, I'm not to be satisfied with the amount of grain mostly in the sky.
Is there a way I can make a rough chape around the sky as to set a different noise reduction for that area ?
Or perhaps is it possible to select by color range ?
I learned a trick awhile back that might be helpful. Set your sharpening and noise reduction where you want them, then hold down the option key and slowly move the "Mask" slider under Sharpen to the right. As you slide you'll see large portions of the screen go white, with the contrast areas (for instance, the house edges and the plants) going black. Those white areas are where your noise being reduced, and with skies, you should be able to get them pretty clean. Additionally, using the brush tool to remove noise should be helpful, too - set a pretty large feather to make that work.
As you said, this is mostly grain that you see in the sky, not digital noise. You are probably not going to achieve what you want with simple noise reduction. I think you are going to want to add some blur to the sky.
That you can do with the adjustment brush, and by setting sharpening someplace between -50 and -100.
I have also found that negative clarity will also help produce some blur.
The color mask will help you in the smaller areas.
I'm really happy there are tools for that in LR. I was kind of worried as I have quite a few skies in the same situation.
I'll try that and get back here with feedback on what I'm able to achieve.
Yep its grain, but its close to digital noise as well.
Especially for that Kodak Gold 200 asa film stock, when I zoom in, I can see lots of individual red points of colors in the blue sky. Its to be expected with a consumer film stock though... I'll try that brush and see what I manage to do.
I didn't mean to imply that there is no digital noise. You will get some from the scanner. Those red points may be color noise as well as "noise" from the original film. Lightroom handles color noise well. So, before you use the blurring brush. run noise reduction over the entire photo.
For the workflow order you would then recommend, first applying the noise reduction over the entire photo, and only then using the blurring brush to correct specific areas ?