Noise removal is really an inexhaustible topic. Actual removal procedures are several, even if not infinite in number. In accordance with this theory, we’re offering a second, simpler and perhaps even more effective procedure for removing color noise. All we use for reducing this annoying phenomenon are Photoshop’s amazing layer management, general effect modes and the Gaussian Blur feature. Beginners are encouraged to follow!
Today’s sample image is a photo part. It has been taken in poor lighting, and the purple shirt shows an easily visible, strong color noise.
Duplicate the original layer on the Layers palette, or click Layer/Duplicate Layer. Switch the general effect modes for the layers from Normal to Color. As we’re about to filter color noise, only color changes will affect the general effect of the layers.
Make sure the upper layer is selected.
Click Filter/Gaussian Blur to blur this layer. Set a medium value for Radius. The higher the value, the stronger the noise filtering, and the duller the colors become. The lower the value, the more natural the color effect looks, and the smaller the degree of noise filtering. The value is also affected by the size of the photo and the extent of visible noise. A value of 5 to 10 is usually enough. You can specify higher values if the noise is more obstinate, but for weaker effects, even a value under 5 can be enough. We have used 6.5. You can see the result on the original picture if Preview is selected.
If you are done, click Layer/Flatten Image to merge the layers, and save your photo afterwards. You can easily spot the result of filtering now. The graininess that still remains is the so-called luminance noise, which has been dealt with in an earlier tip.
Most of the time, the procedure makes colors duller, but you can help this by slightly increasing saturation. Click Image/Adjustments/Hue/Saturation to do so.
Before / After