A New Way to Remove Moire

[John Wheeler]

I am new to RP and was encouraged by another RP member to go ahead and put up a post here about a new technique I recently developed to remove not just the color component of Camera Sensor based Moire patterns (well known techniques) yet also the luminosity component of these Moire patterns (typically the more difficult part to do). The beauty of the approach is that it is simple to implement and I found that it worked well on 19 of 20 images I tried. All it took for many images was the addition of a single Hue/Sat adjustment Layer and adjusting the Hue and Sat sliders. I have posted the details on my blog as well as a screencast demonstrating the technique at

A New Way to Remove Morie

Some images require using multiple Masked Hue/Sat Adjustment Layers to optimize the results if the optimum adjustment point varies across an image with such Moire patterns.

Feedback/suggestions appreciated. Thanks in advance. Hope this is helpful.
John Wheeler

[Der_W]

Hi John,

I like your technique, pretty clever idea :-)!

However I wonder if you really need the white layer in between, because it's "overwritten" by the color layer above anyways.
I see its uses as a preview, but personally I like the color preview better.
Maybe you could just mention that you don't really need the white layer for anything but previewing, so that the watchers aren't "forced" to use it if they don't need it?

Otherwise great technique!

[John Wheeler]

Thanks for the feedback Jonas.
The white layer is only used to expose the luminosity to allow addressing it separately. Here is a quote from the text in my blog:

-The all white layer used to expose the image luminosity can actually be any neutral color solid layer (e.g. black, gray, white)
- The all white layer used to expose the image luminosity is for viewing the luminosity only. Once the luminosity component of the Moiré pattern has been phased away, that layer can be hidden or removed.

I usually have a propensity for including lots of detail yet from other feedback, many have requested I follow the KISS principle (Keep It Simple Stupid). I figured that for the Moire patterns that were mostly color patterns with minimal luminosity component, many might have an issue finding the optimum point in the sliders with the color striations still present. Sounds like you found a way that works better for you. Glad you enjoyed the technique.
John

[Tony W]

Hi John, and a big welcome to RetouchPro. What a fantastic first post.

I have been using technique illustrated by Dan Margulis in Prof. Photoshop which employs duplicate image in Lab with inverted apply image to remove the moire. This seems to work very well for the very limited number of images I have encountered so far. But it is good to have a choice of methods.

Not studied your detail workflow but did have a quick play (on your posted images) while the technique works well I did have a small issue (I suspect user error!). In selecting the area for the paint on colour blend I seem to have missed the correct shade and painted sloppily over the moire area. The final image the moire was gone but in doing so I had changed the shirt colour quite considerably - noticeable in the main due to poorly executed painting (no mask!).

I intend to try this out a lot more and am sure that this will be another valuable technique to add to the arsenal.

[John Wheeler]

Thanks for the welcome Tony, much appreciated
My technique does not work on all moire patterns. It only helps when there is some "phase" separation in the color channels. So it's an incremental tool to the tool box, not a replacement tool.

I should point out that it works best on the original image bits instead of highly compressed JPEG images for that reason. JPEG highly compresses the color channel while maintaining more of the luminosity channel.

BTW, that was my first ever screencast. That was a real experience. I too when recording the video picked too gray a color for repairing the shirt. When done, I decided not to re-record the whole think. I did not spend too much time on alternate ways of replacing the color because many before this technique have demonstrated good techniques to do so (and also I have a lot to learn about painting cleanly as well ). For me masking off both the areas for luminosity correction and for color correction is advisable as standard practice. One technique I have seen others use for the color correction portion is using a blur of the existing image. That helps maintain any local color variations as well. My plan was to summarize some of those techniques when I do Part 2 of 2 of the screencast.
Thanks again
John

[Boneappetit]

Welcome to RPRO John: I just saw your video, fantastic, great job... Keep em coming !

[amica999]

Neat technique. Some of us have linked your video to FB, so you should get more hits :-)