Moiré is the colorful banding that appears when a fine pattern in an image is even finer than the pattern of the pixels on a camera’s sensor. It’s frequently found in tightly patterned textiles such as wool suits, but it can appear anywhere repetitive details form a tiny pattern.
Avoiding moiré in the first place can be tricky. If you see it in the image preview on the back of the camera, consider zooming in closer or moving closer to the subject in hopes that the pattern will be enlarged enough that the moiré disappears. Failing that, ensure that the camera is set to its highest resolution and try stopping down to the minimum aperture available on your lens. Hopefully, these adjustments will eliminate the moiré. But, if they don’t, here’s my favorite way to eliminate this unwanted color banding in Photoshop.
There are a dozen different ways to eliminate moiré in post-processing. My favorite, however, is the simplest. That’s why it’s my favorite, in fact: because it’s so simple. It’s only two steps—you could even cut it down to just one!
The optional first step is to make a selection around an area that needs to be repaired. On a shirt or a jacket, for instance, the selection would include the entire garment, even if only a portion of it needs to be repaired. Make sure the edges of the selection are well delineated from the background. I use the Select and Mask control to really refine the edge of the selection.
If you’re only repairing a tiny area of a garment, you may be able to get away without a selection. I like to use a selection just to ensure the next step will be contained and won’t spill onto the background at all. But without that selection, the fix really is just a single step, and that step is quite simple!
Because the banding that appears is primarily color, rather than luminance, it can typically be repaired with color-specific controls. Namely, it can be painted away with a soft-edged paintbrush set to the ideal color.
I start by selecting the Paintbrush tool and then option-click (or alt-click) in the area of the scene that contains the color that should replace the moiré banding. On a navy blue jacket, for instance, you would select a neighboring true navy blue. (On a gray jacket, you would select a neighboring gray, and so on.) Then, with the brush’s opacity and flow set low, to 25% or less, you can click and drag to paint away the moiré with the correct color. It may take multiple passes to build up the change, and it may require re-selecting nearby colors to fine-tune the change. But, ultimately, painting away the banding with the correct color is the simplest way to eliminate moiré.
If you do experience any luminance banding (i.e., you change the color and you can still see bands of lighter or darker areas in the moiré), set the paintbrush’s mode to Lighten in order to lighten darker bands, or Darken to darken lighter bands. This isn’t always necessary, but if you do encounter luminance banding in your moiré, repairing it is just as easy as painting it away with the correct color and the correct paintbrush mode. That’s all there is to it.