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

[Aaron]

So I have talked with the Plant Manager on a number occasions about measuring conductivity and PH of fountain solution and he always replies with it doesn't matter.

Does it?

And if so, what kind of issues would it cause if they don't maintain an acceptable level? Would the effects be worse when printing Staccato?

[G_Town]

So I have talked with the Plant Manager on a number occasions about measuring conductivity and PH of fountain solution and he always replies with it doesn't matter.

Does it?

And if so, what kind of issues would it cause if they don't maintain an acceptable level? Would the effects be worse when printing Staccato?

Well yes I know it is an issue as it needs to be within a acceptable range I think scumming and tinting will result if its to low ( I maybe completely wrong here I'm no pressman) and yes any press issue is going to be multiplied when using an FM screening like staccato as it's much less forgiving as conventional AM screening.

I'll talk to our platemaker/pressman tomorrow and correct myself if need be.

[Aaron]

Thanks G.

We measured the fountain solution conductivity this morning and it was 1400. Is it better to have a higher level? It seems a bit low but I'm no pressman.

What should the conductivity be? And what about water tank temps? What are my fellow staccato runners doing? I can't ask the plant manager because it would just stir the nest if you know what I mean.

[Lumpy]

I've been told it could also breakdown the ink if not set up correctly. I would think you'd need some standards in place to eliminate variables.

[Aaron]

Yeah that's the problem. We have never had any kind of standard when it came to fountain solution cond. and PH. So I'm trying to figure out what we should shooting for so we can try to keep it at that standard from now on. And doing this delicately because the plant manager is old school and will argue until his face is blue that cond. and PH don't make any difference...

[Lumpy]

Get the Ink tech or plate tech involved. Thats sort of their job. Maybe get the manager involved in the meeting(s) with the techs so he or she can become educated.

[G_Town]

Talked to the pressman (he's been doing it since the 60's knows his stuff).

At our shop he said the conductivity should be at 1800 and the PH should be between 3.9 and 4.2.

The main problems he said you'll see is scumming on the plate and increased dot gain.

I'll ask him about the water tanks temps here in a minute.

[Aaron]

Thanks G! Also, could you ask him what fountain solution you guys are using? We are using Prisco 2351.

[G_Town]

HDA 61-alcohol substitute and Pressmax 280 CON-etch

[Aaron]

Do you guys run staccato?

[G_Town]

Alas no conventional AM here.

I have had limited experience at another shop and what I was told is that FM is less forgiving to bad press conditions and that the pressman need to know that and keep the tolerances tight or you'll have nothing but problems.

[Aaron]

thanks G. That's what I keep hearing as well. I appreciate the help. I'll see what I can do about the fountain solution situation.

[G_Town]

No problem and good luck with the Plant Manager with the blinders on, that's always fun :tongue:

[EyeTech]

Conductivity...1500 - 1650
pH................4.5 to 5.5 - use buffered fount to prevent overdosing, I think most fount solutions are like this these days
temps...........9˚c or 48.2˚f
alcohol..........8% (if you use it)

Keep everything clean, that includes water pans/filters/reservoirs

Conductivity can show the presence of unwanted contaminants such as calcium in the water supply - if you're having problems on a regular basis, stripping, plate blinding or just a high build up of 'silty' deposits in the pans then you may need an RO (reverse osmosis) unit to clean up the incoming supply.

To say that the conductivity doesn't matter is neglecting a major aspect of troubleshooting press issues. imho.

[Lumpy]

Hey Eyetech,
Where'd you get the conductivity info from? Its pretty informative. Is it accurate? If so, I'd like to pass it on to our plant manager for his records.
Thanks.