Moire are ugly patterns sometimes seen on images that have been scanned into a computer. They are interference caused by a failure to properly scan fine details, and they give the image a wavy look. Fortunately, using Photoshop, it is fairly easy to remove this problem with your image.
Scan your image into your computer. Use the maximum resolution your scanner and its software allow. Open Photoshop. Click "File" and then click "Open." Browse to the image file and select it.
Select "Filter," then "Noise," and click "Median." Make the Radius setting about 1 or 2. Then select "Image," then "Image Size." Change the image size and resolution to what you want. Because you scanned the image in at maximum, this will probably mean reducing it. Make sure "bicubic sampling" is checked. Go to "View," then click "Fit to View."
Select "Filter," then "Sharpen" and click "Unsharp Mask." Start out by making the Amount about 75 percent, the Radius 2 and the Threshold 3. Use the preview to adjust these settings to your particular image, until the image is clear of the moire patterns.