Dot Gain

[Slagneb]

What could be some of the causes of dot gain on press??

 

[david123music]

Depends, is it all jobs or just a job?
Look at your prepress not just in the press room. Could be the water - do you have a reverse osmosis unit? Alcohol balance - test for conductivity.

Bad or old blankets
Print Speed
Roller Pressure too high
Water / Damp Mix
Naff paper and inks will also effect your result

Incorrect linear setting of Platesetter for plate type (Speed/Focus/Power)
Output engine (RiP) not calibrated and then inturn calibrated for the press
Therefore incorrect PPF data going too the press

That's for starters

 

[gordo]

What could be some of the causes of dot gain on press??

Dot gain is a characteristic of the process so every aspect from plate imaging to the press delivery station participates.

gordon p

 

[GJOHN]

Dot gain

Dot gain

From an ink formulator's perspective:
Lower the tack (tack is the force to split the ink film-stickiness) of an ink, the higher the dot gain. The higher the film thicknesss of the ink on press (weak ink- lower pigment strength), the higher the dot gain. Over emulsified ink (too much water in ink) will print full. Lower the press speed, the higher the dot gain. Too aggressive fountain solution can break the ink down and it can cause the viscosity and yield value of an ink to go down drastically and it can print too full. Poor transfer from the blanket can result in higher dot gain. If the paper is too porous it can cause higher dot gain.
Hope this helps.

 

[CD102]

You could also mention possible gripper problems, too much back pressure.

 

[printnewb]

What could be some of the causes of dot gain on press??

Could you be more specific? Dot gain on a press is a normal occurrence.