Computer-To-Plate(CTP) technology has a unique technique for printing halftones known as Frequency Modulation (FM) screening, or stochastic printing.
Conventional offset screening has an Amplitude Modulation(AM) that is assuredly better, primarily when higher line screens of 175 to 200 are applied in halftone and four-color CMYK process printing.
Offset Printing dots size
In traditional offset printing, pictures are printed using grid-like screens that separate the image into equally spaced dots larger in size in the darker areas and smaller in size in the light areas. In the four-color printing process, other screens are used to reproduce all four colors of CMYK.
CMYK – Cyan, Magenta, Yellow, and Black
Stochastic Printing Dots Size
But, for the Stochastic Printing, pictures are impressed by dots spread inconstantly throughout the image area. The dots are not evenly spaced and arranged in a row or grid, and it diversifies according to the tone value to be printed.
The concept is – that lighter areas have fewer dots, and the darker areas have more dots.
Benefits of Stochastic screening
The printing with stochastic screening allows the benefits of limited ink on the sheet and can be printed with too much detail.
The grain of the image’s film can become noticeable, an imperfection in flesh tones are more visible, containing a small dot is a great challenge on the printing press, very unforgiving on the press, required a set controls have to be performed, 20% more dot gain than conventional, proofing is challenging.
Benefits of Offset screens
Conventional offset screens (AM) have the benefits of the higher latitude of varying color density on the printing press, more forgiving halftone reproduction, high-grade printing of large quantities of ink transfer on paper, and the better print of one and two-color printing. Metallic image halftones have a more significant impact and work better for skin tones.