Moir is the name for swirling, oddly colorful artifacts Moir is usually seen in a tightly woven fabric, plaid textures or a tweed style jacket. Moir doesn’t pop up very often. When it does, it’s pretty much a full on disaster for the photograph. The screenshot below shows moir in all of its colorful, turbulent, image ruining glory. No, it can’t be passed off as a “special effect.” Darn it.
Moir happens when the frequency of the pixel pattern of the sensor closely matches up with the frequency of a pattern in a subject.The best fix for moir is to rotate the camera slightly to disrupt that frequency clash. The problem is that moir is almost invisible until the photo is viewed at 100% so it’s rarely solved at the time of the shoot. The scenario that happens most often is seeing the image for the first time in Lightroom just before a cry of anguish goes up followed by the panic that the thought of a reshoot brings.
Mastering the moire’ menace
While there are come “cures” available in Photoshop, Lightroom offers the best solution for this unfortunate situation.
- Start by entering the Develop module (D.)
- Click the Adjustment brush or press K.
- Double click any slider that is not centered in the dialog to return it to the zero position.
- Check auto mask box then tap the O key to show the mask.
- Paint over the area affected by the moire’ blight.
- Once it’s covered, tap O to hide the mask.Making the mask is the hardest part.
- Once it’s finished, move the Moire’ slider to the right. Somewhere in the 60’s to 70’s the moire’ just disappears. Magic? Yes. Yes, it is.
More moir on the way
As more of the new, ultra high megapixel cameras like Nikon’s D800E & D810 or Canon’s just announced 5DsR without anti aliasing / low pass filters get used for shooting fabrics in interiors, portraits or fashion, moir will become more common. Fortunately, the fix is already in place in Lightroom. By the way, it’s in Camera Raw’s Adjustment brush in Photoshop and Bridge too!