Arandell Corporation

David Koteski, VP, Arandell Prepress

This is my third and last article in this series. In my two previous articles I explained what stochastic printing is, and the responsibilities throughout the production process flow specific to stochastic printing. In this article I will discuss the pitfalls of stochastic printing. As with any specialty application within a pressroom, there are also potential pitfalls that you may face.  Even after proper file and proof preparation, press finger printing and developing the appropriate plate curves, there are still hurdles you need to be prepared for.

The following are just a few of the potential pitfalls of printing stochastic;

• Ink Piling - due to the higher dot gain encountered with Stochastic screening you will experience both plate and blanket ink piling.
• Ink Savings - fact or fiction.  Gray Component Replacement (GCR) will lead to greater ink savings than stochastic screening.
• Reduced Blanket life - a direct result of increased blanket washes due to ink piling.
• Reduced Plate life - a direct result of increased blanket washes due to ink piling.
• Increased Blanket Washes - a direct result of ink piling.
• Paper waste - a direct result of the increased blanket washes.
• Increased Press Maintenance - a direct result of increased blanket washes due to ink piling and the need for proper blanket and roller conditioning.

When not to use stochastic screening

• Poor separations - keep in mind that stochastic screening greatly enhances your separations. Poor separations will only look worse.
• Flesh tones that have not been properly balanced. There is a tendency for poorly color-corrected flesh tones to appear “rashy or choppy.”
• Lack of knowledge by your client, separator and/or printer.

So where do we go from here? Customer and separator education is the most critical step in the process and with proper education, preparation and planning, the results of stochastic screening are well worth the additional work.

David Koteski, VP, Arandell Prepress

I recently wrote an article on the differences between and the advantages of stochastic and conventional printing. Click here to read my last article.

To continue the conversation, today I will address what steps need to be taken into consideration when running a stochastic screen in a web offset environment.

Client Responsibilities:

• Consult with your current suppliers or industry trade groups to get other opinions. Does your catalog have a lot of flesh tones, shadow or reverse texts? What has been their experience with similar catalog designs?
•  Define your goals and objectives - what is it you are hoping to achieve? What elements in your design would you like to draw attention to? A catalog selling makeup would like to highlight different features than a clothing retailer…
• Determine Paper Specifications. Grade #2 versus Coated Groundwood, matte, satin and silks…as with any printing method, the choice of paper can affect how the end product appears. Viewing finished samples of like-catalogs will help you decide if your paper choice is appropriate for your products.

These are all areas that need to be taken into consideration by the client that will have a direct impact on whether or not to utilize stochastic screening

Color Separator Responsibilities:

What type of proofs will your separator provide?:

• AM screened proofs (150 LS)
• FM screened proofs  (25 micron)
• Epson / Inkjet Proofs

How will your separator manage your images?:

• Image resolution (300 DPI vs. 400 DPI)
• Pick-up images/repurposing of images
• Image/file compression, i.e. JPEG

Keep in mind that any type of compression will strip critical data from your images. This somewhat defeats the purpose of printing a higher line screen, yet many separators apply compression in order to save space.

Printer Responsibilities:

When approaching a stochastic workflow within your printing plant you need to resolve the following areas first.

• 25 micron (285 LS) versus 20 micron (365 LS) - which is best for your plant and client base?
• Stabilize plate production - restrict variables that can contribute to problems on press.
• Finger print the presses - you need to have a firm handle on the color gamut, ink characteristics, dot gain, etc. before you can build the appropriate plate curves.
• Test and modify prior to using on live jobs.

In my next blog I will address the potential pitfalls of stochastic screening.

David Koteski, VP, Arandell Prepress

Have you been given the option of printing stochastic versus using a conventional 150 or 175 line screen? 

What are the advantages and disadvantages of the two?

Would your catalog benefit from changing your printing techniques?

 In my 25 years in the prepress industry, I have learned that changing from stochastic to conventional or vice versa can make the difference between good and GREAT printing.

What is stochastic printing, and how does it differ from conventional screening?

Stochastic screening utilizes a much smaller dot that is randomly placed throughout the images. Click here to view an up-close example. As a result, stochastic printing, images have a continuous tone feel. Also, with the smaller dot size utilized in stochastic screening, you are actually running the equivalent of a 285-line screen when using 25 micron or 365-line screen when running 20 micron. This is what contributes to stochastic’s ability to reproduce much finer detail than conventional screening.

Conventional screening utilizes a larger dot and is placed along a grid (creating screen angles).  This results in a more obvious dot pattern, and a rosette-like pattern. This pattern is most noticeable in your mid-tone areas such as flesh tones. Click here to view a up-close example.

Some of the clear advantages to stochastic printing are:

• Improved detail and definition
• Reversed text prints cleaner
• Improved shadow detail
• Wider color gamut

These advantages can also work against you. In later discussions I will address the potential pitfalls of stochastic screening and how to avoid them.

In my next blog I will address what steps need to be taken into consideration when running a stochastic screen in a web offset environment.

David Koteski, VP, Arandell Prepress

When choosing a printer, many clients overlook the importance of how it might impact their prepress production workflow and specifications. Although most large commercial web offset printers have similar prepress and plate requirements, there are inherent differences that need to be addressed prior to preparing your final files and proofs.

A variety of conditions need to be taken into consideration when preparing your photography, separations and proofs prior to printing. Here are just a few that come to my mind:

1. Will this job print sheetfed, web offset or possibly gravure?

Proof and file requirements change with each printing method. You will have to ask your printer the best practice methods to ensure the best possible quality.

2. Will these materials be repurposed for other media, i.e. newspaper, web, VDP, etc.?

Different media requires different quality images. When in doubt, always err to the side of critical quality. You can always repurpose your materials for a lower quality standard more easily than you can repurpose your materials for a higher quality standard.

3.  What type of paper will I be printing on?

Changing papers, even if it is the “same paper” produced at a different mill, can create a different effect. Make sure you know the best prepress practices for your paper choice.

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