Removing Moire patterns

[Herbert123]

Hey guys and girls,

Here is a quick technique to remove moire patterns in your images. Convert the affected area to greyscale with a white layer set to Color blend mode, then add a hue/saturation adjustment layer between the white layer and the subject.

Use a layer mask to control the exact area, and then use the Hue and Saturation sliders to remove the moire pattern.

Finally, add a colour layer at the top to bring back the original colour (use eye dropper tool), and optionally adjust the settings, and amend the comp with additional adjustments if required.

Original image:
http://olegvolk.net/gallery/d/41585-1/m ... s_9120.jpg

Before & after:

before.jpg

after.jpg

Yes, I am aware the colours do not match exactly - playing around with the colour layer and further small adjustments would take care of that. I did not have that much time to get it exactly right.

Example PLD file:
http://www.estructor.altervista.org/pl/moire.pld

Do you know other moire removal techniques?

[photoken]

This seemed like a good candidate for a simple technique, since the moire pattern is limited to the blue colour of the stripes.

So, I used a Hue Editor adjustment layer and used its eyedropper tool to set a point on the curve corresponding to the darkest value of the moire pattern. Then I lightened that point, after setting a point on either side of it to limit the effect to that specified point:

moire HE settings.jpg

The result:

moire removed b.jpg

I also added a Curves adjustment layer and targetted its adjustment to the blue stripes to darken them back to the original value.

The layers look like this:

moire layers.jpg

[Herbert123]

Nice! Of course, that will work too. Much simpler.

[photoken]

Nice! Of course, that will work too. Much simpler.

It ain't perfect, though. The entire blouse is lightened, and if there happened to be other areas of the same blue colour in the image they would be affected by the Hue Editor too. That Curves adjustment layer doesn't quite restore the values enough for my liking.

If I had to do it again, I'd try to first create a lasso for her blouse and use that selection as a Luminosity Mask (with the colours reversed) for the Hue Editor and Curves adjustment layers. I think that would keep the adjustments limited to only the stripes....