2 Minute Photoshop Tricks Guide: Noise Reduction

Step 1:First open an image that has a lot of noise in Photoshop. Images with a lot of noise will look speckled with red, green and sometime blue dots. Other times noise will take other forms, but digital noise almost always comes from shooting a picture in a digital camera while using a high ISO or film speed.

Step 2: Go to the “Image” menu then “mode” then “Lab color” this will convert the image from the RGB mode to the lightnes and a and b mode. Lab color mode splits the image into a lightness channel that stores the black and white information of the image along with the detail and two color channels a and b that just store color information.

Step 3: Since most digital noise resides in the a and b channels of the image in LAB mode, and most of the detail is in the lightness channel we can effectively remove noise from the image by carefully blurring the a and b channels and slightly sharpening the lightness channel.

To blur the a and b channels simply open up your channels pallet and select the "a" channel by clicking on it in the pallet. You should notice your image turn a bunch of funny shades of grey. If your channels pallet isn’t visible check to see if it’s docked with the layers pallet, if not just go to the window menu and select channels.

Step 4: Now go to the filter menu and select noise then median.

Step 5: Adjust the settings so your image looses the rough feel but not so much as to totally smooth your whole image into one massive blob. Then do the same thing with your "b" channel.

Step 6:Now select the lightness channel and go to the filter menu then sharpen – unsharp mask. This step sharpens the lightness channel. The settings you use for both the blurring of the a and b channels and the sharpening of the lightness channel will depend on the size of your image and the amount of noise. It best to try your settings on the conservative end of things at first then see how your image looks. If the settings were too low just undo and repeat the steps with more aggressive settings.

Step 7: After finishing the sharpening simply go to the image menu and select mode then RGB. Your image should now be less noise with a very minimal loss of sharpness.