How to Sharpen Photo without Increasing Noise Visibility
Sometimes it happens that we need to sharpen photos for which there is noise, for example, pictures taken at night. But overall increase in photo sharpness increases and the noise visibility also. How to be in this situation? I can show you one method in Photoshop, how to avoid it.
First of all you should find some appropriate photo to work with. I prefer to use this one. Open up this photo and start the tutorial. Go to Channel panel (Window > Channels). The first step is to look at the channels palette and determine which color channel best represents the area we want to capture. To the right, shown from top to bottom, you can see the red, blue, and green channels for this image. It’s obvious that the red channel contains the most information because it is most light. Click on the red channel and drag it down to the new channel button to create copy of it.
We got the copy as you can se on the above picture. Then apply for copied channel Filter > Stylize > Glowing Edges with similar settings to these:
Now we have effect like this:
Hold the Ctrl button and click the Red copy thumbnail in the channels palette to load selection of this channel.
After that we can delete this channel: click on the Red copy channel and drag it down to the delete current channel button to delete it. Then go to layers palette (Window > Layers) and press Ctrl+H to hide selection temporary, but donâ€™t remove selection for now! It is important! Then apply Filter > Sharpen > Unsharp Mask with some suitable presets for the photo. Pay your attention that for each photo presets should be individual. I tried following presets:
See the result now:
Now, we have some selected area, but it is hidden for now, press Ctrl+H again to make it visible. Then press Ctrl+J to duplicate selected area to new layer. Then apply Filter > Sharpen > Sharpen Edges:
That is it for now. We sharpened photo without increasing the noise visibility. Hope, you got some interesting knowledge from this tutorial.