Blotchy printing

[curiosity]

can you show us micro shots of ur last pic?

 

[swp66]

This one was done 20 Micron Stacatto. See attached.

 

[swp66]

1) have the plates previously had that slight blotchy look to them? Your picture shows an uneven colour on the plate dot.

2) Has the operator loaded fresh ink in, washed up and started water dials below scum point?

Your press sheet dot looks like serverly emulsified ink which can easily be done if water dials are left where they normally run on paper stocks or the ink has been left in the ink duct and continuously sprayed with anti skin each night.

We are using Fuji LH-PJ plates and have been using them for a few years. As far as I know they have always had that grainy texture look to them. As for what the press operator has done, I can only go by what he is telling me. He said he has tried several different variations on how much water is being used. He also said he striped the rollers. I am not a press expert, far from it, but it looks to me like the dot is being squashed. Like too much pressure maybe. I am going to speak with the press guys and see what else we can do to resolve this issue.

 

[curiosity]

A .20 difference in substrate thickness between "good" (.06mil) prints and "bad"(.26mil).
So far the only difference, right? (imo the micro shots look similar)
Press experts, what say you?

 

[Alois Senefelder]

Gentlemen and swp66,


The Plate Images look OK, the "Grainy Appearance" .... all Lithographic Plate Coatings are "Translucent" what you are seeing is a slight cast from the Anodizing.

This is a - On Press problem, Emulsified Ink, Too much pressure.


Regards, Alois