The first thing to do when removing noise or grain in Lightroom is to import your image and move to the Develop tab. Once you are in the Develop tab, move over to the left toolbar and use the navigator tool to zoom in on a 1:1 ratio. Using the right toolbar, scroll down until you reach the Detail panel and open this up! For standard digital noise reduction, use the Luminance, Detail, and Contrast sliders. Luminance will smooth out the pixels and get rid of overall noise. Detail will save the details in your image, and higher you slide it the more detail will be saved. Contrast determines which pixels to smooth out in relation to the contrast of your image. For colour noise reduction use the Colour, Detail, and Smoothness sliders. Colour will change the blue, red and green pixels to a neutral tone. This is determined by using proximity-match, meaning it uses colours around it to determine the proper grading. The Detail slider does the same thing in this case as it does when you are reducing digital noise: preserves the details in your photo. Smoothness is similar to what the Luminance slider does. This slider smooths out the colours and pixels to reduce the grain and noise.