New to Auto: trapping top white?

[Stinkhorn Press]

getting less new to the auto, but still.

we trap UB/top colors .75pt, works well for our tolerances usually.

do you trap top whites? how much?

[Atownsend]

I would choke rather than trap the UB. I dont ever trap the top white. I think that is just asking for blurriness. I do usually choke the underbase 1-2px in PS. Sometimes, but not often I trap top colors. Usually just choking the underbase does the job without the need for a trap, and we are on an old gauntlet.

[Gilligan]

You trap/choke so that if you are off a smidge no white peaks out.  If you do this with top white then there is ALWAYS white "peaking out"... it's the top white sitting on the shirt with no base.  If you don't choke then only get peaking where the registration is off a tiny bit, if at all.

[Colin]

We don't choke or trap our highlite whites.  They line up exact.

We only choke our base whites so the top color covers the white base so no "layers" appear.  For us that is .5 pt.

If you can't keep registration that tightly, check your tensions/pressures/press level etc...

[Doug S]

Same here we choke the ub .5 and sometimes .375.   Also on some of your more fine designs where you have to cover the ub with some really fine lines of art we will use say a 200 mesh for the ub and 180's for the top colors.

[jvanick]

we almost always choke .5pt or .6pt on the center of the line.. which results in either a .25 or .3 choke.

99% of the time with tri-lock we're in register, or just a minor tweak.

If we were to do a 1pt choke (on the center) we'd never have to touch a micro, but you could see a bit of the overlap which I hate.

[Dottonedan]

A very nice guy contacted me in a rush and was up against time. Looked like a clear cut sim process halftone job. He had me revise it, cuz his press needs 2pt trap and to make all of the halftones solid. I haven't had a request like that in 25 years.

[ScreenPrinter123]

We don't choke or trap our highlite whites.  They line up exact.

We only choke our base whites so the top color covers the white base so no "layers" appear.  For us that is .5 pt.

If you can't keep registration that tightly, check your tensions/pressures/press level etc...

Is that .5 aligned to inside such that it is the same as 1 pt aligned to middle?

[Colin]

.25 in .25 out.  So a .5 middle aligned.

[Stinkhorn Press]

trap/choke - i use the terms pretty much interchangeably.

90% the time for top colors, we shrink (put a non-printing stroke color in the art) around the UB white.
sometimes, with art say, made in AI by someone else and not for screen printing nesc, and handled by me in corel - it's just easier to grow the top color instead (as long as that isn't mucking up some butt registration needs). makes for a muddier print tho.

with whites, however, I started shrinking the TOP white rather than the UB. i don't mind the shelf effect (and no customers are yet picky enough to notice) AND it makes it a bit easier to print when
a) that top white is butt registered with some runny color like black (i know better press calibration would reduce this) or
b) attempting to print a top white followed by 1 or 2 colors that lift too much to be printed before that top white (yellow and reds). i'm trying to figure out best how to make films and print order so that we can send 90% of our jobs around the press once. buying a second flash would help, but with an 8/10 we rarely have the space for it, let alone it PLUS a cooldown station...

[Stinkhorn Press]

moving old question forward.

for top colors we use .75 (from center) choke on UB white.
for top white we moved to a .4-.5 choke (from center) choke on our UB white.

that said - when, if ever, do you NOT print true butt register on top of that UB, especially with black and/or more-likely-to-bleed colors touching each other??

for example attach - blue shirt. white UB (under the red text, not under the black cross). small, skinny red text. black cross. and top white.
if i have 5000 shirts to print with something like this, what do you choke if you want to go around once on the press and have 1 flash??

[Doug S]

1st of all I would pray it was a light blue shirt so I wouldn't need a highlight white.  If a highlight was needed, I would do as follows:

I would choke the black so that there would be a small gutter between it and the ub.  I'd also put a small gutter between the red and highlight white by putting an outside not middle stroke on the red.
Using good wet on wet inks such as wilflex I'd print in this order.

Black
Ub
Flash
Cool down
Red
Highlight

I'm not going to lie, I'd be using a second flash here.  I'm sure there are many here with better advice.  Forgive my iPhone typing.

[jvanick]

1st of all I would pray it was a light blue shirt so I wouldn't need a highlight white.  If a highlight was needed, I would do as follows:

I would choke the black so that there would be a small gutter between it and the ub.  I'd also put a small gutter between the red and highlight white by putting an outside not middle stroke on the red.
Using good wet on wet inks such as wilflex I'd print in this order.

Black
Ub
Flash
Cool down
Red
Highlight

I'm not going to lie, I'd be using a second flash here.  I'm sure there are many here with better advice.  Forgive my iPhone typing.

I'd run this the exact same way as Doug.

I run black first a LOT, depending on what kind of shirts they are.

[Stinkhorn Press]

1st of all I would pray it was a light blue shirt so I wouldn't need a highlight white.  If a highlight was needed, I would do as follows:

I would choke the black so that there would be a small gutter between it and the ub.  I'd also put a small gutter between the red and highlight white by putting an outside not middle stroke on the red.
Using good wet on wet inks such as wilflex I'd print in this order.

Black
Ub
Flash
Cool down
Red
Highlight

I'm not going to lie, I'd be using a second flash here.  I'm sure there are many here with better advice.  Forgive my iPhone typing.

thanks! anyone else?
exactly what we are looking to hear.
how small of a space you talking for both your
1 black to UB white gutter  and
2 red to highlight white gap

a second flash would also be quite helpful, true.

(we don't have a 2nd flash and will probably go around twice in the end (not this exact art, but same idea) but are willing to set up a couple more screens a couple of ways to test out options that could get us only once around in the future)

[Doug S]

If it were me, I would choke the black .75 middle and the red outside .25 to .375 especially if you have great screens.