4 Color Process confusion

[Doug S]

Ok here goes.  Today I had a 4 color process job to get out the door.  First of all the picture was not a great resolution but the only one they had.  I explained that it would not look as crisp because it was an old polaroid photo and the face I had to pull out of it was just a small part of the pic and even scanning at 450 dpi it didn't help much.  They told me that they didn't care because they had to have his pic on the shirt. 

I wasn't happy with the low res print on the shirt but I only had low res to start with.  What was really throwing me is that every 3rd or 4th shirt wasn't printing as dark.  Almost a faded look.  I just releveled the pallets and also made sure the heads were parallel to the pallets as well.  I used a dime and penny on four corners of the pallet to do it.  I was thinking that maybe the frame I used even though checking it first might have been a little warped.  But then I thought that even if that frame had been warped that all of the prints would've looked somewhat the same.  I was using 330 mesh screens for the process ink but probably should have used 300 mesh.  Has anyone else ever had that issue and if so, what was the remedy?

I do an average of 1 4cp job a month.  I'm not new to it but today I felt like a newbie.  To top it all off, I was 3 shirts away from being finished and  my black process screen popped and that screen had never been in production.  I was using 35 psi on each head. 

Just one of those days I guess.

[Underbase37]

It sounds like unlevel pallets, I know you said you just leveled them but when we had this problem it was this. Put a marker on the pallet or pallets & see if it is constant. Also I have seen this happen if someone forgets to put a layer of pallet tape on. On the flip side of that I have also used a layer of pallet tape to fix/ Band Aid this problem too. Sucks about the screen always love that it seems to happen that way.

Murphy37

[Doug S]

I appreciate the reply.  I didn't think about the extra layer of pallet tape.  Looks like another half of a day of releveling for me.

[Inkworks]

I mic. my pallet tape and .0035" or about the same thickness of a human hair. You guys are finding that difference shows up in registration?

[ScreenFoo]

Not to say I ever enjoy it, but have done decent 4cp prints on presses that needed leveling pretty badly--if you're within even a sixteenth of an inch you shouldn't see massive shifts ONLY because of that.  To me, seps, screen tension, and blade sharpness IME play much larger parts in the solution type of problem it sounds like you're describing.  New screen popping first run is also a red flag...

[ABuffington]

How old is the press?
If an old M&R or any press that uses air cylinders for squeegee pressure they can stick, get weak and become worn and not hold pressure.

May work for a few prints and then boom, the print goes light.
I would first print all pallets and check what numbered pallet went light.
Then print another test on a light pallet to see if prints dark on a test to see if the air cylinders are causing the issue.

Also are there other presses in the shop and is the air head level dropping when all are printing at once?
Sometimes the pipes can't push the enough air through.  Helps to have a storage tank of air near the presses.
probably not the issue if you have servo heads however.

If the pallet always prints light then I would check off contact once more.  Or just crank down the pressure and
add some base to the colors!  I often find that out of the can color is way too strong and can be cut with halftone base.
We would control color balance the job on press this way if it was too saturated a print or if there was a color shift.
This allowed for a little more squeegee pressure and we could pull back over saturated color with more halftone base.
A poor fix, but hey we were on a tight print schedule.  I have found however that I can pull out more secondary and tertiary color
with this add halftone base trick, it also helps if the positives were all output at the same angle rather than in a rosette.

Al

[Doug S]

How old is the press?
If an old M&R or any press that uses air cylinders for squeegee pressure they can stick, get weak and become worn and not hold pressure.

May work for a few prints and then boom, the print goes light.
I would first print all pallets and check what numbered pallet went light.
Then print another test on a light pallet to see if prints dark on a test to see if the air cylinders are causing the issue.

Also are there other presses in the shop and is the air head level dropping when all are printing at once?
Sometimes the pipes can't push the enough air through.  Helps to have a storage tank of air near the presses.
probably not the issue if you have servo heads however.



If the pallet always prints light then I would check off contact once more.  Or just crank down the pressure and
add some base to the colors!  I often find that out of the can color is way too strong and can be cut with halftone base.
We would control color balance the job on press this way if it was too saturated a print or if there was a color shift.
This allowed for a little more squeegee pressure and we could pull back over saturated color with more halftone base.
A poor fix, but hey we were on a tight print schedule.  I have found however that I can pull out more secondary and tertiary color
with this add halftone base trick, it also helps if the positives were all output at the same angle rather than in a rosette.

Al

The press is a 2010 Sportsman e servo drive and ac heads.   I ran the films at 55 lpi and 22.5 angle.  I have never owned or  tried halftone base but I probably need to.  I know the black process always seems too thick.  Also I probably should've stuck with a 280 mesh and definitely not a 330 mesh.  I was using shurloc frames.

[GaryG]

Yes sounds like some halftone base to lube it up through the 330.
It should at least make it a more consistent shear to help ink lay
for the light prints, and even it all out. Might not have to keep releveling.

[mk162]

if I do process, which I try not to, it's done through a 305.  At that you could also crank your lpi up a little as well, maybe to 60-65.

Make sure you stir the inks, process inks have a funky base and can be really hard to get to print if they aren't stirred.

Last resort, use an additive.  I don't like that option because over time your inks will shift depending on how much additive gets put back in the bucket.

[Underbase37]

You should not need to be releveling a lot,  if you are you might want to look at a few other things. Base was a must on our old challanger ( air heads ) base is still a must on a lot of 4cp for me. 355-305 on almost all 4cp jobs for us. As for the pallet tape band-aid, layering, & this is not a fix, also its not to keep things in register, just reduce off contact of that pallet.

Murphy37