Brisque to Lotem 800 II / Lotem Quantum Family - Kodak

58 Chapter 2 – Configuring and Calibrating the Lotem 800 II / Lotem Quantum Family from the Brisque WorkstationAngle SetTo designate the screen angles for the different color separations. Angle setoptions are: Conventional, Shifted, and Pseudo Conventional, whichmodify the angles set in the default Screen Sets. These variations are aresult of extensive laboratory and field tests, designed to prevent moiré andother interference patterns.1. To define an Angle set, click the Angle button and from the menu,select an Angle set option. The screening angles for each separation, asdefined by the Angle set, appear in the angle boxes beneath theseparation names.2. To customize the screening angle for a specific separation, clickinside the Screening Angle box in the column below the separationname, and type in a new angle.When screening a Job containing Spot Colors, the resulting Plate Exposealways outputs the Spot Colors at 45 degrees, regardless of the Spot Angleparameters defined in the Screen Set.Tip: When Angles are set to 45 degrees for any CMYK color separation, youcan set the automatically fine-tune all Screen Frequency values (including Spotcolors) to prevent patterns. To use this feature check the Adjust Scr. Freq. box.You can also enter an Angle value of 0, but a Screen Frequency adjustment onlyfor that particular color separation will be calculated.Screen FrequencyThe Screen frequency, also known as screen ruling or mesh, determines thenumber of “printed dots" rows per millimeter, that are exposed on theplate.Common screen frequencies range from 3 - 12 lpi. Screen frequenciesdefined in the default Screen Sets provided by Creo have been calculated togive the best dot structure and to be least likely to produce unwantedpatterns.Tip: Screen frequencies above approximately 7 lpi typically result in differentdot gain characteristics on press. To compensate for this, use a ToneReproduction curve. See Tone Reproduction on page 42.To define a Screen Frequency for all separations, select the Adjust checkbox and type a value in the Scr. Freq. box.