Determination method of drying of varnish coating on printing sheet - offset printing

[thaiha]

Dear all,
I'm facing with problem of varnish coating on the surface of printing sheet. It is not dry completly after 8 hours of curring time. Normally, our standard for curring time for varnish coating is 8 - 12hours. So, I need advice from all of you, do we have any formal method to check drying of varnish coating ? pls support!

 

[Cornishpastythighs]

A question for you. What is different about this run of varnish if it usually cures ok after 10hrs? Different supplier, More humidity, different press. If you have been successfully running varnish before what has changed?

 

[keith1]

Probably the same thing that's creating your wrinkling problem. Humidity.

 

[thaiha]

Dear all,
1/ The printing press room is dehumidity condition,
2/ and all of parameter as humidity, temperature in standard (the temperature we control in 26 - 30 oC, humidity 55 - 65%) these parameters we control daily.
3/ Same supplier
4/ We do trial for different machine to see the result, and the result is same.

 

[keith1]

Sounds like the paper could have been affected before it entered your shop. Often you can feel waves if you run your fingers across the paper pile.

 

[Alois Senefelder]

Hello thaiha,

Questions: - 1) Are using IR formulated OP gloss Varnish on the Press ?

2) Have you checked the Temperature of the incoming sheets ?



Regards, Alois