Perform Noise Reduction on an HDR Photograph
In Photoshop Elements, you can edit your tone-mapped HDR image further. Reducing noise is similar to sharpening. Remember, you want to preserve the Background layer of your HDR image in Photoshop Elements before applying additional filters.
Create a duplicate layer, and then choose Filter→Noise→Reduce Noise. The figure shows the Reduce Noise dialog box open with the default settings being applied to the sky.
You can perform sharpening and noise reduction first from trial and error. If you wait to sharpen and remove noise until after you make other adjustments (contrast, levels, color, saturation, and so on), you might run into an unfortunate side effect: Sharpening and noise removal alter the look of the image so much that you need to go back and perform many of the same tasks again.
Tackle dust and other distractions before you make other changes so everything is in place for the tone and brightness changes. To clean up an imperfection, select the Clone Stamp tool, Alt-click (Windows) or Option-click (Mac) a good area near the imperfection, and then click the marred spot.
Wait until after sharpening/noise reduction because those operations increase or reduce edge contrast, and you don't want to give them any additional material to alter that isn’t in the original.