noise reduction

In part 1 of the Lightroom 4 noise reduction tutorial I talked about different types of noises in digital photographs, global and selective noise reduction methods in Lightroom 4. So, I guess you are ready to process some ‘noisy’ images now. If you haven’t read the part 1 of this tutorial, please read it first. Read: Lightroom 4 Noise reduction Tutorial Part 1 Global Noise Reduction I am using a high ISO image here to show you how to reduce the noise. This image only has luminance noise. Using another image I will show you how to remove color noise. As I said In part one, when you do global NR method, it applies to the entire image. I am using the loupe window to preview the areas where there is more noise. Below are the steps (please click on the images to enlarge): The photo is shot with my canon 1000D at ISO 1600 Step 1: Open your image in the develop module in Lightroom and click on the detail panel. It drops down the NR box. Click to enlarge Step 2: Once you open the detail panel box, click on the marker to enable it. Now you will notice that the cursor changed to a 'cross' symbol. Click on an area where there is more noise. The loupe window previews this area. Step 3: Click on the 1:1 button on the navigation window. For effective noise reduction, I would recommend you to zoom in the image to 1:1 magnification. This will help you to see the changes effectively. Step 4: Now you can only see the area where you have zoomed in. Use the noise reduction sliders to reduce the noise to a desired level. But don't overdo it. As I have said in the part of this tutorial, removing all noise makes the pic soft. Step 5: After your the process you want to see the changes that has taken place. For that, click on the before and after views button at the bottom (as shown in the screenshot above) This will help you to compare the level of noise reduction you applied in the image. This particular image did not have color noise. But I will show you how to remove color noise with another image. Color Noise Reduction I have opened another image which has some color noise. Here, I have magnified the image to 3:1 so that the color noise is more visible. The image preview on the left shows color noise and the preview on the right is after the color noise reduction. You can notice the changes. The red and blue splotches are disappeared. That's it. Above are the steps for global NR in Lightroom 4. While you are doing this process, you should zoom out the image to the original state to ensure that the image has enough details. I have mentioned about this in part 1 of this tutorial. Now, let me show you the selective noise reduction in Lightroom 4. Selective noise reduction As I have said before, the adjustment brush in Lightroom 4 is used for selective NR. In part 1, I have shown you where the adjustment brush is located and how to enable it. Step 1: Click on the adjustment brush button. It is located just below the histogram window (see the screenshot above). Now move the noise slider to the right to decrease the noise wherever you are going to paint with the adjustment brush. I have highlighted the brush settings box in the screenshot above. Use that setting now if you don't know what those sliders mean. Step 2: Now paint the area where you want to reduce the noise. The red area shows where you have painted with the adjustment brush. You can disable the red area by pressing the alphabet key 'O'. This is how adjustment brush is used to selectively remove noise from images. Please note that adjustment brush removes only luminance noise. So if you want to remove color noise separately, remove it globally, and then use adjustment slider to bring out the details in the areas you don't want to remove the noise. I have mentioned this in part 1, too. Some dos and don'ts of noise reduction Now let me come to the last part of this tutorial. Please read this since it is very important. Dos Reduce the noise only if it is really necessary. Just because you shot the image at high ISO, doesn't mean that you have to reduce noise. High ISO images from some DSLRs hardly have noise in them. Reduce the noise based on the output. Noise reduction for digital sharing is different from the noise reduction for printing purpose. Read more on this in part 1 of this tutorial. Before doing this process zoom in the image. Don'ts Do not completely remove the noise. Noise is good. Over noise reduction makes the image soft, devoid of details. Always do noise reduction at the end of your workflow. Reduce noise just before sharpening and after the exposure adjustments. So, that is all about noise reduction in Lightroom 4. I hope you find these methods useful. This is just a standard workflow. It varies from person to person. If you know a better workflow, please let me know.