What is going on?!?!

[presspressmerch]

Can someone help me with this madness.

Working on a 9c sim job today, everything looks great but the black screen has a pattern not present on the film. Trying to wrap my head around this issue.

We’re using either a 230 or 305 shurloc (forgot to verify before leaving work). Accurip to 4880 at 65 lpi, solid black film.

So it’s the screen, I assume, but how? What am I missing.

I’m attaching a photo of the film and two photos of the isolated black print.

HELP!


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[Doug S]

What angle were the halftones printed on the film?

[mimosatexas]

Looks like mesh interference to me. If you did 65 lp on a 230 you're going to have issues I think where ever dots line up with the mesh

[Dottonedan]

I’ll bet you’re using panel mesh. That it Static frames.

I’ve seen many of panel frames and static frames do this. The stretching is not 100% square opening. Probably never will be. It’s hard to get perfect.  I typically see an inconsistency in tension.

Art could be too big for the mesh “live area, but not that common.
Trying to hold too fine of a dot  in 1/4 tone and highlight on that mesh.
Could be Low tension all over. .

For those fine dots, could be emulsion coating too thin/too thick.

[Maxie]

Looks to me like a badly exposed screen.
The vacuum is not 100%.
Why are you using 65 lpi?     Much more difficult top 3xpose fhan 55 or 45.
Why exposure system are you using?
How good is your vacuum?

[tonypep]

There is a huge result differential between 230 and 305 mesh, especially at 65 DPI. So yes, as mentioned, interference is most likely involved.
Guess what? There are a myriad of variables involved. Difficult to diagnose without being on site. If you have the time I would advise to change only one variable at a time. Otherwise, inconsistent results may come up. It most likely depends on how often this type of work comes around. Standards and Practices.
This is a craft and also an Industry
Off the Soap Box tp

[presspressmerch]

What angle were the halftones printed on the film?

22.5


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[presspressmerch]

I’ll bet you’re using panel mesh. That it Static frames.

I’ve seen many of panel frames and static frames do this. The stretching is not 100% square opening. Probably never will be. It’s hard to get perfect.  I typically see an inconsistency in tension.

Art could be too big for the mesh “live area, but not that common.
Trying to hold too fine of a dot  in 1/4 tone and highlight on that mesh.
Could be Low tension all over. .

For those fine dots, could be emulsion coating too thin/too thick.

My first thought was the squareness of the panel. We use shurloc which seem to be fairly consistent in terms of square an tension.

I’ll check the tension when i get in, but my guess would be high 20’s

Lots of variables!



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[presspressmerch]

Looks to me like a badly exposed screen.
The vacuum is not 100%.
Why are you using 65 lpi?     Much more difficult top 3xpose fhan 55 or 45.
Why exposure system are you using?
How good is your vacuum?

For sure. This screen would be reshot even if I did not have this issue. I don’t think this is an exposure issue though.

We shoot 65 frequently for our sim jobs. Transitions are much better.

3140, good vacuum


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[presspressmerch]

Looks like mesh interference to me. If you did 65 lp on a 230 you're going to have issues I think where ever dots line up with the mesh

This makes sense. Screen guy might have pulled the wrong screen.


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[presspressmerch]

There is a huge result differential between 230 and 305 mesh, especially at 65 DPI. So yes, as mentioned, interference is most likely involved.
Guess what? There are a myriad of variables involved. Difficult to diagnose without being on site. If you have the time I would advise to change only one variable at a time. Otherwise, inconsistent results may come up. It most likely depends on how often this type of work comes around. Standards and Practices.
This is a craft and also an Industry
Off the Soap Box tp

Starting with the screen this morning. I have a strong feeling it’s a 230 and interference.

We do this work enough that this needs to be resolved.


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[inkman996]

We did a ton of testing at my shop recently to get rid of moire issues. We I found is 22.5 is not always the best angle to go with. I can now shoot a 65lpi on a 230 using 37.5 degrees, doesn't mean I will get all the small dots but the moire is not there.

[mimosatexas]

Similarly, I use 25 and 27.5 as angles sometimes and have mitigates this exact issue before.

[presspressmerch]

Thanks for the input everyone. My particular issue was resolved by shooting the image on a 305!


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