Stochastic Screening

View or download a PDF file of this article: PDF (8k)

Stochastic means, "involving a random variable". Stochastic Screening uses randomly placed dots instead of traditional line screens and screen angles. Stochastic screening uses frequency modulated screening. This screening system varies the frequency of the dot to simulate different shades of gray (as opposed to amplitude screen modifying size of dot). Stochastic brands - Diamond screen & Crystal Raster. Latest generation screens the data twice for improved 4/c reproduction and avoids graininess in large flat areas.

Benefits:

• Produces more detail. Clothing / Medical

• No screen angles. No moiré

• All digital workflow.

• Registration not as critical on press

• Touch and bump plates are infinite

• Less tonal shifts on press because of smaller dots

• Photo realistic results

• Higher ink densities on press used to increase color brilliance
  

So why don't we use it more often?

• Can not be proofed with Fuji final proof. We proof at 230 l/s to simulate the stochastic screen.

• Scans are produced the traditional way and the screening is applied at the plate making stage.

• Large flat tints still look a little grainy.

Example: ACME Photography Project

The project goal was to create a printed piece with a photo-realistic look.

Paper:

80# Centura Gloss Cover

Ink:

1st Pass - Silver and PMS 1375
2nd Pass is dry - 4/c process plus a second black for text to overprint silver. Let sheet completely dry before printing other side.

Is this process more expensive? Prepress is quoted as a regular 6/c job. Print is quoted as a twice through the press dry pass because of the metallic Ink. Drying time will determine the turnaround required.

View or download the following PDF samples of Stochastic printwork:

Sample 1 PDF (292k)

Sample 2 PDF (148k)

Sample 3 PDF (56k)

Sample 4 PDF (240k)