from Positive to Negative plates

[Dario]

About ctp plates, what problems could arise migrating from positive plates (kodak electra) to negative plates (kodak sonora)?
TVI curve problems maybe?
Never done this before

 

[Magnus59]

About ctp plates, what problems could arise migrating from positive plates (kodak electra) to negative plates (kodak sonora)?
TVI curve problems maybe?
Never done this before

No problems whatsoever,

We have gone from negative (830N & Trillian) to positive (Electra) and back to negative (Sonora) with no affect on press.
It's not like the old days where you got dot gain from negs and dot loss from positives, you're imaging the precise dots on the plate regardless of whether you write the image or the non-image areas.

 

[Dario]

No problems whatsoever,

thanks!!

 

[panos valakos]

The positive plates from any manufacturer ,when the laser power and drum speed is correct
gives on plate for 50% file dot around 48 % on plate.
For negative plates when laser power is okay ,gives on plate for 50% file dot, around 55-60 % on plate depending on CTP type.
For negative plates usually 5% to 8% cut back in the rip is required with comparison to positive plates.
In detail you have to linearise the plate and get a plate curve for any type of plate +ve or -ve
and then use the print curves according to paper or press.