HyperFlex was originally developed to work with Maxtone. The first implementation of HyperFlex was designed to replace energy lost from the removal of Maxtone dots, and so HyperFlex light valves were created at the grid points where Maxtone dots had been removed. This on-the-grid HyperFlex is known as HyperFlex Classic. Configuring HyperFlex Classic will place small light valves back on the grid.
Process template with Maxtone and HyperFlex Classic setting
TIFF with Maxtone and HyperFlex Classic appearing in AM grid points
With further development, additional controls were added to allow you to place light valves around individual AM halftone dots, increasing the amount of UV energy being added to the plate. This is known as HyperFlex Advanced. When HyperFlex Advanced is configured, you must set the point at which HyperFlex Advanced light valves are turned off. This is known as the limit percentage.
HyperFlex Advanced can be freely positioned at a user-defined point from the halftone dot center. Controls allow you to specify how far away from the dot center HyperFlex will be placed when it begins, and how far from dot centers it will be placed at the point that it ends.
Process template setting, showing theoretical settings for use with AM screening
Best practice is to always use merge mode for Advanced HyperFlex. The use of specific start and end positions generally produces inconsistent results. This is because of variations in plate batches, fluctuations in UV exposures, and changes in washout and press conditions. At the time that you fingerprint, results may be good, but the following week, conditions may change and plate results could suddenly be unacceptable. For this reason, you should always use HyperFlex Advanced in merge mode. Merge mode places HyperFlex light valves at a distance halfway between neighboring dot centers.
To activate merge mode, you must ensure that the Start and End numbers are greater than the number entered in Merge Distance. It is recommended that you type 2 for Start and End, and type 1 for Merge Distance. This will force all HyperFlex into the merge position.
Process template setting set to place HyperFlex in merge position
Note: HyperFlex Classic is not selected, because Classic is not visible when used with AM screening.
HyperFlex in merge position with AM dots
Note: HyperFlex creates small light valves in the mask between the dots.
The last concept that must be understood with HyperFlex is the use of feathering. Extreme highlights require the greatest amount of extra UV energy to help activate the plate and create strong printing dots. Moving up the tonal scale, more overall energy is reaching the plate and less extra energy is required to be replaced by HyperFlex light valves. Kodak developed HyperFlex to gradually reduce the amount of extra light valve energy by tapering off the size of the light valves. This is done through a process called feathering. Feathering works by dividing the area where HyperFlex Advanced is applied into five zones and progressively reduces the size of HyperFlex in each zone, until the point at which it is no longer applied.
HyperFlex Advanced with feathering
The use of HyperFlex Classic and Advanced together allows you a large amount of control in applying extra energy to activate flexo plates in the highlight areas. With very thin plates for narrow-web use, at high line screens, it may be possible to only use HyperFlex Classic to achieve good results. However, as plates get thicker, and as plates are used for mid and wide web applications, it becomes very important that dots are as strong as they can possibly be. For this reason, you should always use both HyperFlex Classic and Advanced when applying Maxtone Screening. This will ensure the strongest possible plates and consistent, high-quality results.
Best practice is to set HyperFlex Advanced and Classic to be equal in the lowest percentage. This creates the most evenly diffused UV energy boost to plate.
Left: Maxtone only; center: Maxtone with HyperFlex Classic; right: Maxtone with HyperFlex Classic and Advanced