Working in Camera RAW
Because HDR generally adds a bit of noise to the image, we can open the image in Camera RAW by choosing File > Open in Photoshop and selecting the image. Just before clicking the Open button, switch your File Type in the drop-down list to Camera RAW, and this will open up the TIFF image in Camera RAW. From there, you can adjust the luminance slider under the noise reduction to clean up the noise (see Figure 5).
In this instance, I am cleaning up the noise in the cloud areas, but I don’t want to do any noise reduction in the mountains. To achieve this, I am going to open the file a second time. For this instance, I will remove the noise reduction that I originally placed on the file. Once the second file is open, I can move the files as layers on top of one another and mask out the mountains in the noise-treated layer (see Figure 6). This now gives me the best of both worlds in this file.