the changes in the behavior of PressSync curves when used in Imaging Engine 18.0.1 or later,
how to have the old behavior with the new Imaging Engine version.
Behavior in Imaging Engine 18.0 and Earlier
When a standard PressSync curve with a "Max" value below 100% is used, solids will be screened at a gray level equal to this "Max" value.
In the example below, the PressSync curve selected for Cyan (F40) has a "Max" value set to 96%. When this curve is used to RIP a job, the solids/100% tones will be screened using a gray level of 96%.
You can see this in the curve below (X=100%, Y=96%).
New Behavior in Imaging Engine 18.0.1 and Later
From Imaging Engine 18.0.1 onwards, the "Max" value has a different effect: when a standard PressSync curve with a "Max" value below 100% is used, solids will not be adjusted to that maximum value, but will use the 100% level of the screen.
For screens that do not use surface screening, solids will be kept as solids (not screened).
For screens that use surface screening, solids will use the surface screening pattern defined for 100% in the screen.
However, tones just below 100% in the job (for example 99.9%) will be screened to a gray level equal to the "Max" value (for example 96%).
You can see this in Curve Pilot 18.0.1, when looking at a PressSync curve on a graph. In the example below, you can see that for the tone just below 100%, the curve adjusts to 96%. For 100% however, the curve goes to 100%.
The end of the curve is slanted rather than going straight up, because the curve is constructed from 512 points.
How to Obtain the Old Behavior in Imaging Engine 18.0.1 or Later
From Imaging Engine / Curve Pilot 18.0.1 onwards, all PressSync curves have the "Keep 100%" option selected by default. This means that 100% tones are kept solid (or screened with the pattern applicable to the 100% tones, when using a screen with surface screening effects).
For basic PressSync curves, it is not possible to change this. However, you can use Flexible PressSync curves to change the handling of the 100% tones. From Curve Pilot 18.0.1 onwards, Flexible PressSync curves are included in the basic PressSync license.
How to Enable Flexible PressSync Curves and Change the "Keep100%" Option?
Open the Curve Pilot and go to Edit > Preferences....
Enable "Flexible PressSync".
When Flexible PressSync is enabled, you will be able to set Flexible PressSync options when working with PressSync curves.
In the PressSync curve set editor, click the "Select Curve Names..." button.
Next to the PressSync letter and number, you will see a triangle button. Click this button to open a dialog containing the Flexible PressSync options.
Here you can change the "Maximum Value" and the "Keep 100%" options.
To have your curve handle the 100% tones as in previous versions, deselect the "Keep 100%" option. When using this Flexible PressSync curve, solids will be screened at your "Maximum Value" (for example 96%).