waterbased coating

[ar17]

we are printing high ink coverage cmyk jobs on one of client which requires us to cure or allow drying of the printed sheets for 3 to 4 days. and we sometimes encounter color shifts after drying. I tried applying some waterbased varnish to accelerate curing time and lessen color shifts but I need to justify that the cost of additional inline varnish will not increase the price of our process. please help giving reasons how to justify this additional process or will there be better alternatives for this drying and color-shifting issues. thanks

 

[robb]

I'm guessing that you are using an ink with dryer retarders (sta-open) in it. If so, that is the problem.

 

[SteveSuffRIT]

Just so I'm clear, its the 4/c process (CMYK) that is shifting color, not any spot (PMS) colors.
80% of dry-back or dry-down occurs within first 30 min.
Typical dry-back amounts are -0.03C, -0.05M, -0.01Y, -0.15K.

Are you sure the color is shifting from drying and it's not color variation from during the press run?
Can you measure the dry-back with Delta E, before vs. after?
Steve Suffoletto​

 

[ar17]

I will record . yes the color shifts during drying... next day, the print is pale compared to the digital proof already. specially the red shades...

 

[turbotom1052]

If this dry back issue happens on all jobs then you might think about compensating for this in pre press. Not sure your aware of this but there's a process called press fingerprinting, that synchronizes your plate output to the way the press prints. Do yourself a favor and try to avoid just running more ink on press to compensate for this dry back. What you should be striving for is to have plates output with enough dot to get the job to pint with a reasonable ink film thickness. Just piling on more ink to compensate, will come with many problems!!!

 

[ar17]

this is interesting thread... same question, why is my print turning pale or the good red print going down in color the next day. this is solid printing so no way to compensate in prepress. what we do is increase the density and hope that after drying, we hit the expected color. thanks

 

[Alois Senefelder]

Hello ar17,

You need to be more "precise" about the print problem.

Questions: Are you printing just "Solids"?

2) On what substrate - Paper/ Board?

3) Printing Method, Litho/Flexo?

4) If Litho why not use a "Higher Pigmented Ink"?

5) Why not have the customer "Pass" colour on the actual substrate? rather than matching a Digital Print?

6) Trial different "Brand Substrates"

7) Printing Ink "Dry -back" is a known problem, just part of the printing process!

Regards, Alois