Removing Image Capture Noise in Channels in Photoshop

Here you will work on individual channels to remove noise:

1. Open your image.
2. Zoom in on the area of the image where you can see the background sky and beach up close.
3. Look through the three channels to confirm that the Blue channel is indeed the noisiest one. Also see that the Green channel has some noise, but not as much as the Blue channel. So your strategy here will be to push hard on the smoothing of the Blue channel. Then you will smooth the Green channel some. You will leave the Red channel as is to hold the focus of the image together.
4. While still zoomed in so that you can see the details of the smoothing’s impact, activate the Blue channel.
5. Now choose Filter --> Noise --> Dust & Scratches. The Dust & Scratches dialog box appears. Feel free to experiment with the other noise reduction tools. Each tool works well on various kinds of patterns. Zoom in to view the effects of each tool. Be sure to select the Preview check box so that you can see the effects without actually having to apply them to an image. If you are unsure as to which effect you like, create a couple of layers and apply a different effect to each one for comparison.
6. Set the Radius amount to 1 pixel, and then try 2, and then 3 pixels to view their impact. You will see that 3 pixels of radius really softens the noise and the image on the Blue channel. Go ahead and apply the 3 pixels. Note that you could use the Threshold value to apply the Dust & Scratches tool to only portions of the image. Experiment with Threshold values here to see which portions. For this image, set Threshold to 0.
7. While still zoomed in, activate the Green channel.
8. Now choose Filter --> Noise --> Dust & Scratches. The Dust & Scratches dialog box appears.
9. Set the Radius amount to 1 pixel. This will be sufficient to smooth the noise on this channel.
10. Now activate the composite RGB view of the image. Notice how the composite image is still held together in terms of focus. Praise the Red channel! And more sharpening help is on the way in step 11. Now zoom in to view the original image and compare  it to the working image. You will see that much of the noise has been removed, but the hard edge detail is still preserved.
11. If you would like to add a bit more sharpness to the focus of your image, you can choose Filter --> Sharpen --> either Unsharp Mask or Smart Sharpen (see the next section for details on how to apply sharpening in this instance).