Moire on 100% solid areas - Randomly

[LuckyFlyinROUSH]

Every once and a while we've been getting Moire on 100% big block text or big open space areas. The entire print will have this large moire pattern on it. I assume this is just the way the screen was stretched? Typically this happens with our 160 mesh only. Our EOM around 25%, but I wouldn't think it would matter as it's only on wide open areas.

No issues with other mesh counts and halftones.

[Homer]

we used to get that with our own stretched screens, not really moire, but a funky wave pattern. It's because we sucked at stretching screens .......... haven't seen  it in years since going to Smesh statics...

[Dottonedan]

Let me guess.  Static frames or panel lock mesh.  Both that are factory stretched. Doesn't matter who you get them from, they all provide poor stretching alignment.  They just do it too fast and don't pay close attention like you would if stretching in your own shop. Typically, you don't see this in the print on solid art (unless, it's drastic or large) rainbow like arches that can be noticed more easily.  Small or tiny bands get buried and I think he stretching shops gear their quality for this type of work where it just gets hidden.


I've said this for a long time.  The rush process of the stretching supplied mesh on panel frames or Static frames are rushed too fast. They don't have "perfect thread alignment" in mind for this type of supplier.  Thats my hunch.

We are still getting random moire issues.  I've put tape on the side of the ones that I've gotten moire or more like (mesh interference) from so I can be sure to confirm that my problem is the mesh.

We coat the same, expose the same and I still get moire "randomly".   Like 2 out of 7 frames will have moire if using any halftones.  and it's not my angle (22.5).  70% of the screens provide great halftones at the same lip and same screen angle....while some don't.  I've tried different angles (and get the same results). I've tried lowering LPI...and go through 3 screens to get one good one without moire.  It's MESH alignment.

[BP]

Every once and a while we've been getting Moire on 100% big block text or big open space areas. The entire print will have this large moire pattern on it. I assume this is just the way the screen was stretched? Typically this happens with our 160 mesh only. Our EOM around 25%, but I wouldn't think it would matter as it's only on wide open areas.

No issues with other mesh counts and halftones.

does this happen when you are printing a color on top of a underbase?

[Doug B]

  I would guess it might be an interaction between the screen mesh alignment as Dan said and the mesh of the garment you are printing on. I have seen times you could get a halftone moire on one shirt and not on the next but I could see it on a 100% print area also.

[Colin]

Is this only when you print the same mesh count (or within 15 tpi of each other) on top of same mesh count?

Do you Primarily see this with colors that are more translucent?

If so, the answer is a little different than what was written above - but are cousins in terms of the reason why.

[LuckyFlyinROUSH]

We only use statics with permanent block out now. High TN, typically about 30 nt. These two are - 28nt - 160 mesh. Both of them. I guess your right its more of a wave pattern than a moire. Kinda hard to see it in the attached picture in the Red ink, but it was the only sample I found. IC Graphics purple, and Rutland Dallas Green tend to do this the worst.

If It's going to be an issue of running 160 as base and 160 as top I'm going to be in trouble. I really like the looks of 160 PFP then colors on top for our sub 72 piece runs.

[cleveprint]

We run into the same issue when we use the same mesh counts for the underbase and top color. Regardless of mesh count. Beyond my knowledge of mesh sciences and properties, which is pretty much nothing. Hahaha.

That being said, we are usually using 125s or 140s for the UB and 160s/200s for the top colors. Never do we see the issue pop up doing that.

[LuckyFlyinROUSH]

Well crap. I like using 160s for pfp cus I like the feel of the print. I guess I could try doing 180s as top colors.

[zanegun08]

I think you are hung up on screen mesh, but since you said this happens on Reds, Purples, Greens, I think it is actually the ink.

We have this same issue with inks that don't have much white in the bases.  I think you are actually seeing different opacities or waves of pigment.

I would try to throw in a higher opacity ink, or make the color with more white base, however this does seem to pastel the colors a bit.

We have these same issues with Red, Purples, Greens as well, I don't call it moire, I call it mottling.

Maybe I'm way off on a tangent here, and it is mesh interference, but throw in a different color to see if it solves the issue, I think going higher mesh will increase your problems as less ink will lay down exposing more of the under base.

[LuckyFlyinROUSH]

Maybe. All three colors are the HO versions of straight out of the bucket.

Now that you mention it though, I can't remember once of our mixed colors ever doing it. But we don't typically print mixed colors as solid blocks of color. Typically for simulated process.

[Colin]

I think you are hung up on screen mesh, but since you said this happens on Reds, Purples, Greens, I think it is actually the ink.

We have this same issue with inks that don't have much white in the bases.  I think you are actually seeing different opacities or waves of pigment.

I would try to throw in a higher opacity ink, or make the color with more white base, however this does seem to pastel the colors a bit.

We have these same issues with Red, Purples, Greens as well, I don't call it moire, I call it mottling.

Maybe I'm way off on a tangent here, and it is mesh interference, but throw in a different color to see if it solves the issue, I think going higher mesh will increase your problems as less ink will lay down exposing more of the under base.

Zane - You will see it happen with colors that have greater translucency.

With the same mesh going on top and bottom:

When any ink flows through mesh - it creates micro peaks and valleys from the holes in the mesh.  When you put that same peak and valley pattern on top, but slightly offset you create an interference pattern that looks similar to moire.  When the top color is very translucent, you create a deeper/thicker layer of ink when 2 "valleys" come close to lining up.  When 2 peaks come close to lining up, you get a very thin ink deposit.  Since no mesh is ever stretched the same from screen to screen - you get some really odd patterns sometimes.

Now think of Caribbean water.  Deeper water gets a very rich blue, where water near shore looks very light blue.  This is a similar effect to what you get from the ink.

The more opaque the ink, the less of this you see.

Hope this makes sense!

[Croft]

just had this happen last week , usually happens for us with blues like 286, with a double white base it was bad , we ended up doing a single white base , the blue looked good then added a  white hi light.

[Dottonedan]

To me, everything Colin mentioned all makes sense (starting, still due to a mesh interference issue) or amplified due to the mesh interference.  I'm sure the ink itself on a perfectly straight mesh could still cause some of this heavier deposited areas of ink to show up in print like he said. The mesh (as openings get smaller due to distortion), would amplify this issue.


I'm sure that Ink "color" is also another factor. A few mentioned it happens with colors that have a lot of blues for example.  I remember Ray from Wilflex telling me one time that blue ink particles (A cyan in 4 color process for example), are more oblong shaped. Not round, and therefore tend to coagulate in mesh openings more than any other ink particle that is more like a rounder shape. Don't know how much that impacts a print but for what it's worth.

[LuckyFlyinROUSH]

We started changing mesh counts when it happens and it eliminates the problem. It's really annoying though.