PH and Conductivity in the Pressroom... Does it really matter?

[Lumpy]

EyeTech Beer???

[Aaron]

I appreciate it EyeTech. If the Plant Manager let's me, I'll give it a shot.

[Chilbear]

Aaron - anything to report back? We used 2351 years ago and it was with an alcohol system on a Komori. One thing is if you use Alcohol on press, you measure the ph and alcohol, as the alcohol lowers the surface tension of the water drops. You need a cooler water tank to keep the alcohol in solution. If you have moved to an alcohol substitute (2351 is not a sub - we used 2351+ which is buffered for the water we drink (yuk)) then the mixture of sub to water is a mix designed to get the conductivity to a stable number for your area's water supply. the Prisco rep knows this number and it is his job to get the press printing sharp if you use their stuff.

Big colour swings mean the ink is not milled out correctly on press and stripping (glazing) on the rollers is a culprit. I remember our Prisco rep on the phone saying to run vinegar on the roller train and wash with water not solution to float the paper particles and calcium off the coated paper out of the roller train.

This topic is fun but if the plant/press super does not know this stuff he is the weak variable. To answer your question - absolutely conductivity does matter if you are alcohol free.

[Aaron]

Thanks for the info Chillbear.

I had our plate tech talk to the Prisco rep and he said we are where we need to be. We do use alcohol and drain the tanks every friday. So we have a fresh batch every week. We chill at around 55 degrees and he also said this was good for the plates we are using. I still need to get a PH tester though. We haven't been checking that for years.

I'm starting to think it's the ink. I found out the pressroom isn't rotating inventory when they get a new batch of ink in. But the real shocker is that the pressmen noticed the newest batch if magenta ink looked a lot lighter in the can and no one told me. We called the ink vendor and they said it had nothing to do with the way the ink will look once printed. But I sure find if interesting that the ink appears a lot lighter in the can and I'm getting way too low dot gains for magenta on press.

I measured the solids in LAB and sure enough the new batch of ink was a different color. The L didn't move so much, but the A and B moved to a more yelo.