Fingerprinting

Started by G_Town, October 28, 2010, 07:46:43 PM

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G_Town

October 28, 2010, 07:46:43 PM
So we fingerprinted a press for G7 and it turns out that on our biggest job we fingerprinted it on different units, I asked specifically if we are running the CMYK on the same units, turns out we didn't.

Pressroom manager says a unit is a unit. Now I've always been told they vary from unit to unit.

How screwed are we?

beck

#1
October 29, 2010, 06:42:50 AM
Not sure.

First off, I see problems because you and the Pressroom Mgr. are butting heads on this.  We had the luxury of our Manager running the fingerprint.

When we fingerprinted for G7, we used our standard rotation... K, C, M, Y - 1st & last units open.

In a perfect world, with a brand new press, a unit may be a unit.  But I think we'd all have to agree every press is it's own animal.  We've had jobs that just would not hit for color, they'd swap units, swap rotation, and the job would look completely different.  How he can say "a unit is a unit" is crazy.  Methinks he's taking the easy way out.

beck
Nevertheless....beck has hit the proverbial nail on the head.
Joe

David

#2
October 29, 2010, 07:11:51 AM
Well...  a unit is a unit, but they can still be different. Your Pressroom manager is BSing you.
We have two Lotem 800s, twins in every respect. But, do you think they do the exact same thing? Not on your life.
Same with press units. They may be the same physically, but due to press conditions, wear, inks, and paper, they will print different.
Prepress guy - Retired - Working from home
Livin' la Vida Loca

G_Town

#3
October 29, 2010, 07:41:41 AM
Quote from: beck  on October 29, 2010, 06:42:50 AMNot sure.

First off, I see problems because you and the Pressroom Mgr. are butting heads on this.  We had the luxury of our Manager running the fingerprint.

When we fingerprinted for G7, we used our standard rotation... K, C, M, Y - 1st & last units open.

In a perfect world, with a brand new press, a unit may be a unit.  But I think we'd all have to agree every press is it's own animal.  We've had jobs that just would not hit for color, they'd swap units, swap rotation, and the job would look completely different.  How he can say "a unit is a unit" is crazy.  Methinks he's taking the easy way out.

beck

No not butting heads at all he just was thinking of other work that run in a different rotation but are about 1/10 the number of sheets as our big job, he admits he wishes he would of ran the correct sequence for this job. So far one form off since the new curve no corrections and everything appears OK, guess we dodged a bullet.

Stiv

#4
October 29, 2010, 09:04:43 AM
A unit will have different characteristics than another, as does paper, times of day, humidity, temperature, etc.

Your calibration is better than not calibrating. It also can help with identifying units that may have issues with worn journals or excessive slap.

I think it is a case of the more you know - the more you know you could be better. Chase the tail type of thing. You have to stop and call it good at some point.

G_Town

#5
October 29, 2010, 09:06:46 AM
Quote from: Stiv on October 29, 2010, 09:04:43 AMA unit will have different characteristics than another, as does paper, times of day, humidity, temperature, etc.

Your calibration is better than not calibrating. It also can help with identifying units that may have issues with worn journals or excessive slap.

I think it is a case of the more you know - the more you know you could be better. Chase the tail type of thing. You have to stop and call it good at some point.

Second form in make ready and looking very good after only a couple hundred sheets. :azn:

Ear

#6
October 29, 2010, 10:30:35 AM
The pressman is wrong... all units print differently and need their own curve. They each have their own blankets, rollers and roller pressure and yes, they will all print differently... similar, but still unique. Same goes with roller stripe tests.

We just had all of our presses fingerprinted to G7... I was in on it and have a printout of the curves. There is a lot of difference, from unit to unit. Each 'station' has its own curve, the guy doing the fingerprinting was very specific about this and we run in the same color order, if not, it won't work. In addition, being a web shop, I am using stretch compensation, which is unit specific. Go read your curves... there's no way it's related to merely the ink.
"... profile says he's a seven-foot tall ex-basketball pro, Hindu guru drag queen alien." ~Jet Black

G_Town

#7
October 29, 2010, 11:09:13 AM
Quote from: Earendil on October 29, 2010, 10:30:35 AMThe pressman is wrong... all units print differently and need their own curve. They each have their own blankets, rollers and roller pressure and yes, they will all print differently... similar, but still unique. Same goes with roller stripe tests.

We just had all of our presses fingerprinted to G7... I was in on it and have a printout of the curves. There is a lot of difference, from unit to unit. Each 'station' has its own curve, the guy doing the fingerprinting was very specific about this and we run in the same color order, if not, it won't work. In addition, being a web shop, I am using stretch compensation, which is unit specific. Go read your curves... there's no way it's related to merely the ink.

Slow down Opie I'm on your side! Yes we have a curve for each unit, it just happens we got lucky in that the units are printing close enough that the color is coming out fab after just a few sheets.

Interestingly enough we G7'd this press many months ago and this time the curves changed fairly radically.

What do I care, as long as they can run and leave me alone I'm happy.
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