Noise reduction in post-production

The question of noise reduction is very similar to that of focusing. Some editors prefer to get rid of it at the beginning, while others prefer to fix it in the middle of their project and others at the end. Some apply noise reduction to Camera Raw, others use channel blurs and similar techniques, and still others use Photoshop's tool or special plug-ins. In short, we have a large choice of tools depending on the photo and the amount of noise. I'm going to explain three simple techniques and when they apply, or at least when I'm the one who applies them. 1. Camera Raw Noise Reduction If the image when developed doesn't have an excessive amount of noise, I don't need to open it in Photoshop and if I'm editing it directly in Lightroom, I use the noise reduction panel. To do this, I use the before/after view. The “before” view will correspond to the image already processed of the Salomon tunnel on the Río Tinto in Huelva (Spain). I proceed by using the arrow pointing to the left. Once the view has been edited on its position, I start by adjusting the luminosity values ​​on almost half of the path and with the detail tool, I get some information. Then I do the same with the color. Once these four adjustments are made, I tone down the result or lower the brightness and color values ​​so as not to leave the whole thing detailless and flat. On these photo-tests, I did not carry out this "recovery" so that the settings are obvious. 2. Basic Photoshop Noise Reduction Useful if I have a photo being finalized in Photoshop because I want to make clone-like adjustments and take large areas with similar colors. For example, if I notice a little noise on a clear sky or with small clouds, I have a little Gaussian noise that spreads randomly and evenly over the whole area, I don't complicate my life too much and I uses the basic noise reduction tool with Photoshop's filter. Once the photo is edited, even after the final selective focus, I duplicate the mask and fearlessly...