What's new
Photoshop Gurus Forum

Welcome to Photoshop Gurus forum. Register a free account today to become a member! It's completely free. Once signed in, you'll enjoy an ad-free experience and be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Blotchy areas on gray seamless


Tom Mann

Guru
Messages
7,223
Likes
4,343
I'm not sure about aliasing in area "A" because that problem usually manifests itself obviously only when there is some underlying periodic structure. I'm not sure that there is any real structure in the backdrop other than the weave itself, and IMHO, the junk we are seeing in this area doesn't look anything like the usual Moire patterns one runs into when, say, photographing a tightly patterned cloth with a camera that doesn't have an optical LPF in front of the sensor.

When there is lots of high spatial frequency detail, but no underlying periodicity, if you are undersampling it, then is usually shows up as just an increase in random noise in that area.

What we are seeing could possibly be that effect, but only in the plane of best focus. In the nearby OOF areas, it should be minimal because being OOF means that the high spatial frequencies have been drastically reduced, so without out-of-band high frequencies there can't be aliasing, yet the wormy look is still present, hence my guess that the effect of my hypothetical extreme ACR settings would be visible there, as well.

Let's see what the OP's raw file looks like.

Nite'

T
 

peta62

Guru
Messages
727
Likes
190
Tom Mann - yes, I agree, there is definitely no moire, but there is a possibility that structure, bokeh and noise create some structure, which may catch aliasing and then be magnified by Camera Raw settings. We will see when raw picture arrives.
Good night ( although I already have Saturday morning ;-) ),
Peter
 

Top