moire issue

Hi

I would use frequency separation to separate the high frequency dots from the low frequency moire. To do that:

1. Make 2 duplicates of your image layer
Name the lower - "Low frequency"
Name the Higher - "High Frequency"
2. Select the Low frequency layer and use Filter Gaussian Blur until the dots just say disappear (on your screenshot that was around 1.6 px)
3. Select the High frequency layer
Go to menu Image > Apply Image
Set the source layer to Low Frequency
Set the blending mode to Subtract
Set Scale to 2 *
Set offset to 128 *
Click OK
4. Change the blending mode of the high frequency layer to Linear Light
5. Now use a soft brush on the low frequency layer to paint out the moire using colour picked up from the image. I made a selection first to restrict the brush strokes to  front of the speaker.

[Edit click the image to see the result - without doing that, the forum software introduces more moire in its resizing of the post]

Dave



* Note - the above steps are for 8 bit/channel images. For 16 bit/channel step 3 changes slightly

3. Select the High frequency layer
Go to menu Image > Apply Image
Set the source layer to Low Frequency
Check "Invert" next to channel

Set the blending mode to Add
Set Scale to 2
Set Offset to 0
Click OK

Now carry on with step 4 above

Are the screen shots all 1:1 100% zoom ratio?  I am wondering if it is a monitor thing and depends on zoom ratio. When we used to use flatbed scanners, the trick with them was to scan twice with the image rotated a wee bit for the second scan, and merge them in Photoshop.  That's not helpful in this case though. 

This article has some interesting tips and I think they might even have an Action, which is always welcome when they work.

https://design.tutsplus.com/tutorials/how-to-fix-moire-pattern-in-photoshop--cms-41614

I'd be interested in how you get on if you try it.