Richard Bourque
How to DENOISE ANY PHOTO like MAGIC in Adobe PHOTOSHOP & LIGHTROOM
Updated: Nov 21, 2020
If you prefer to learn through video, click here.
TL;DR is at the bottom.
If you've read my blog "5 things I've learn about photography" you'll know that I HATE noise in my photos. It's gross. It's a weird, random digital artifact from background radiation or something. I want CLEAN and FANCY photos to later put some yummy grain on.
Before we start let's talk about why you have noisy photos. Usually it's because you have your ISO set too high. Your camera's sensor is trying harder to pick up more light that's not there and it's creating visual "static" on your image. Kind of like if you were listening to the radio, you had bad reception, and you keep hearing "SHSHHSHSKHSKSKHSSKHSKHS!!!!!!!!!" Yeah, that's basically the same thing, just audibly. (Not sure if this is factual or not, but it's a good example. I'm not a scientist.)
So let's get started. I'm going to use this photo of an old painting I made way back in the day. I turned my ISO up to 16000 To get the most amount of noise I could in order to best explain.

As you can see, if we zoom in, it's very, VERY noisy.

First, while you have your noisy image
open, and the image layer selected, click on the FILTER tab at the top of your screen. Followed by " Camera Raw Filter". Or use the shortcut "Shift+Ctrl+A".

Then open the "Detail" drop down menu.

If you are using an older version of Camera Raw you may need to click on the two little triangles at the top of the menu, just under your histogram.

Back to the newer Camera Raw
Now click both of the drop-down arrows for Noise Reduction and Color Noise Reduction.

Now, you will need to find a balance here with all these options. There's no perfect answer, or settings for every photo out there, so you will need to play and find a balance between them all.
Here is what I did to solve this EXTREME example.

Let's Compare the Before and After.

Now for a close-up.

There are some drawbacks to this tool. As you can see, there colors are all blurry and blended together. There isn't much you can do about that beside NOT TAKING A PHOTO WITH AN ISO OF 16000! With a lower ISO you'll need less noise correction, therefore, it'll blend the colors less. I also tried adding a TON of sharpness back into the image to clean up the lines and details. It worked OK. Still, make sure your ISO is low in the first place and you won't need to worry about this.
What's great is this also works on 3D renders. Sometimes when you are in a hurry and you need to get out a low-sample render you are stuck with little "fireflies". That's noise and its fixable. Here is a quick example.

(This image is NOT mine. I found it on my computer after I took it to the shop because of some problems it was having. I wish I knew who it belonged to so I could give them a big thumbs up)
I hope this was helpful to you. If you have any questions or feedback, feel free to reach out.
While you're at it, check out the store I put together for prints of my artwork and favorite photos!
Did I mention there is a video version of this tutorial? 😉
TL;DR
Step 1: Filter > Camera Raw Filter > Detail tab
Step 2: Turn up Noise Reduction slider and play with the other sliders until you find a happy balance.