variables to consider to keep dots from growing during the print run

[Stinkhorn Press]

printing on an auto for a couple of months now.

the image with both shirts in it attached are 8 prints apart, the pink shirt 3-4 prints in, dots on the peach (fruity pink on top of yellow) look good.
the green shirt, 8-10 shirts later, they are already getting decidedly muddier.

what do I need to do to keep my dot growth to a minimum during the run.

(white, flash, yellow, flash, pink, blue, purple, flash, green, black)
ink - synergy poly white, wilflex epic (Y, Blue), wilflex PC (pink purple green)
RPM 8/10
8 degree stroke blade
20 inch/sec
28-30 psi
newer 70 duro blades

[AntonySharples]

How are you coating your screens?  Are you putting a back coat on after they dry (squeegee side)?  Creating a tunnel for the ink to travel will decrease any dot gain.  I would also look at squeegee angle, running them perpendicular as well as finding your optimal speed to print at.  Another thing to look at is your off contact to as minimal as possible.

[Stinkhorn Press]

mesh is 225/40 murakami S  mesh.

[Dottonedan]

Just curious, Isn't the one pic at the bottom, the way you are really wanting it to look?

For example, when you first print a halftone blending job, you need to run 3-7 test prints first to get pallets and ink warmed up and flowing (before making a determination on what needs adjusted. Then, once there, start printing on the order garments.

The bottom pic, looks to be closest to what it's intended to be....but sounds like you are not wanting it to drift that way and you feel it's too heavy.


Now, the green, I'd cut that pressure/coverage back by a lot...in my opinion. It seems too stark.

[ffokazak]

I let my colours get picked up a few times before making adjustments as Dan has mentioned. I find red in particular is a colour that becomes stronger after the other screens pick it up, and I adjust my Seps + Pre press accordingly.



In another topic, that peach is surprisingly suggestive haha!

[jvanick]

Reds and some blues are susceptible to peaking as well... try to print those as far at the end of the print order as possible.

Dan is right on with prints settling in... I try to not judge colors for the first 20 prints or so.

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[screenprintguy]

Plus you may need to back off your pressures as everything gets hot from flashing. We notice squeegee rubber soften a bit once all is hot, so I tend to prepare to back pressures almost 10psi at times.

[ScreenFoo]

I think the main point has already been made well--no matter what your gain is on press, managing it properly in the seps is key to making the printing part easy.  I wish I was much better at it. 

How are you coating your screens?  Are you putting a back coat on after they dry (squeegee side)?  Creating a tunnel for the ink to travel will decrease any dot gain.  I would also look at squeegee angle, running them perpendicular as well as finding your optimal speed to print at.  Another thing to look at is your off contact to as minimal as possible.

I'm not quite disagreeing with the beginning of this, but just noting that the 'tunnel for the ink to travel' normally should be as short as possible to limit dot gain.  If you are coating thin thread mesh once, letting it dry shirt side down, and giving it a face coat (I'd do it on the shirt/substrate side,) you should have a very smooth stencil going.  It helps not only for better exposure for those of us suckers still using film, but better ink release during printing as well.

The end is very much proper, agree 100%.

I'd also add if there's any way to go lighter on pressure on successive WOW screens it could help a bit.

[GaryG]

You'll get the sep percentage down after a few tries as not to fill in too much.
Of course minimal off contact.
I'd say try some sharp 70/90/70's too.

[Dottonedan]

Since I did the seps, I'd have to point you all in another direction.

Question,  why flash after the yellow? That red actually needs the yellow to be wet to blend well to create the peach better.

There is 57-58% of yellow near the top area, and 63% yellow -all under the PMS 7424 red. The red over top, in it's darkest area (near the top part) has 50-51% red to create more of a peach color. Keep in mind, we are limited to these colors due to the red being used in the top type. With 63% yellow under this 50%ish red.  There is 18% red down near the bottom of the peach. That 18% seems to almost disappear at bottom as if the ink is very thin. No?

Using S thread, may that be putting down (too much) ink for sim process or halftone work? Maybe? I say that only based on what I've heard. No real experience with Murakami mesh. since it's said to be able to put down more ink, but isn't that really determined by your stencil thickness?

Side note on the purple. The glasses look good, but the outline on type doesn't seem to be pulling it's needed darker contrast when mixing with that halftone blue outline of the type. Maybe change that purple to a slightly deeper or more opaque purple?

[Dottonedan]

I'm thinking the image example on the blue teal shirt is more accurate and it sounds as if you're thinking it's muddier than the white tee.  I don't know why they look so different other than maybe it was too early to tell on the white tees. Like I mentioned, maybe do a few test prints before determining.

To me, the one on the blue shirt seems pretty close to what the original tone of color. If anything, the bottom area of the right peach guy, needs to be a tad more red. (I think it's a peach).

I don't know why the top type (right corner) seems like a different red, as if it's a neon ink. Maybe the photo.

I would like to get that outline heaver/darker on the type.
Also, the bathing suits look "pinkish" on the blue shirts....but beige on the white tee.

You want me to revise anything?

[ol man]

Plus you may need to back off your pressures as everything gets hot from flashing. We notice squeegee rubber soften a bit once all is hot, so I tend to prepare to back pressures almost 10psi at times.

This^^^... Almost every job my guys run, im walking around the press dropping pressure in the first 2 dozen shirts..

[Get Shirts]

I think the question he is really asking is how to manage the dot growth and the answer is experience.  Maybe Dan can share some of his unlimited information with the OP to get that process started, but he will have to learn what works in HIS shop. 

Is the print on the white shirt based?

And whatever that middle fruit is looks foul.


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[Stinkhorn Press]

How are you coating your screens?  Are you putting a back coat on after they dry (squeegee side)?

but just noting that the 'tunnel for the ink to travel' normally should be as short as possible to limit dot gain.  If you are coating thin thread mesh once, letting it dry shirt side down, and giving it a face coat (I'd do it on the shirt/substrate side,) you should have a very smooth stencil going.  It helps not only for better exposure for those of us suckers still using film, but better ink release during printing as well.

we do not yet face or back coat. improving our coating game is probably a necessary next step.

Since I did the seps, I'd have to point you all in another direction.

Question,  why flash after the yellow? That red actually needs the yellow to be wet to blend well to create the peach better.
...
Side note on the purple. The glasses look good, but the outline on type doesn't seem to be pulling it's needed darker contrast when mixing with that halftone blue outline of the type. Maybe change that purple to a slightly deeper or more opaque purple?

Seps looking good, too Dan!

without a flash after the yellow, the red (and everything else, but the red mostly) gets very very mottled and light. (see attached - ok my phone camera really sucks, but on the lower paired print, the red ink is a mush sitting on yellow waves, and losing opacity to boot)

but we can print everything including the green and black WoW after flashing the yellow. I'm happy with a decent print if it needs to go round twice at this point! (as long as the customer agrees it's decent anyway!)

switched to a darker purple, that helped get back to the art look in the words. pms2655

I think the question he is really asking is how to manage the dot growth and the answer is experience. 

that's true and there's no way round it, but this board helps. Once someone has pointed out that a car is purple, i'm very hard pressed to notice that a dinosaur is driving it. I'm stuck on the first fact.

[AntonySharples]

I think the main point has already been made well--no matter what your gain is on press, managing it properly in the seps is key to making the printing part easy.  I wish I was much better at it. 

How are you coating your screens?  Are you putting a back coat on after they dry (squeegee side)?  Creating a tunnel for the ink to travel will decrease any dot gain.  I would also look at squeegee angle, running them perpendicular as well as finding your optimal speed to print at.  Another thing to look at is your off contact to as minimal as possible.

I'm not quite disagreeing with the beginning of this, but just noting that the 'tunnel for the ink to travel' normally should be as short as possible to limit dot gain.  If you are coating thin thread mesh once, letting it dry shirt side down, and giving it a face coat (I'd do it on the shirt/substrate side,) you should have a very smooth stencil going.  It helps not only for better exposure for those of us suckers still using film, but better ink release during printing as well.

The end is very much proper, agree 100%.

I'd also add if there's any way to go lighter on pressure on successive WOW screens it could help a bit.

Back coating creates a cylindrical tunnel, coupled with high shear printing will give a greater fluid pressure head leading to a crisp dot.  Coating substrate side will create a funnel, not a tunnel, and the resulting pressure and thicker gasket will result in increased dot gain.  I'll try to dig up some slides later to illustrate what I'm talking about.