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Moiré Mitigation in Layers of Material

Asher Kelman

OPF Owner/Editor-in-Chief
I have come across an eye sore problem of translucent roller blind cloth, (to lower incident light), overlying window screens, (with tiny mesh to keep out insects). The result is Moiré bands, although fascinatingly psychedelic, are very distracting. It's a problem before any photograph is taken.

Any ideas on how to mitigate this effect. Is there a mesh-weave spacing ratio between the two materials that would reduce the moiré. I guess we could remove the metal screens before a photo session, but still, it's freaky having this moiré pattern floating in space!

Asher
 

Asher Kelman

OPF Owner/Editor-in-Chief
The original moiré has thick, almost horizontal dark bands.

I discovered that rotating the material of the blinds to 45 degrees minimized the moiré, but it was now vertical and at about 10% of the unrotated material. A further 5 degree rotation seemed to decrease the Moiré further.

Asher
 

Doug Kerr

Well-known member
Hi, Asher,

I have come across an eye sore problem of translucent roller blind cloth, (to lower incident light), overlying window screens, (with tiny mesh to keep out insects). The result is Moiré bands, although fascinatingly psychedelic, are very distracting. It's a problem before any photograph is taken.

Any ideas on how to mitigate this effect. Is there a mesh-weave spacing ratio between the two materials that would reduce the moiré.

In fact, often the greater the spacing between the two the less is the effect.

Another helpful step it to place a third layer (a piece of bed sheet) between the two (with spaces on both sides) That might of course produce more overall attenuation than you seek.

Best regards,

Doug
 
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