Friday, January 20, 2012

In One Quarter of a Second on Press

Printing presses whether they're an older manual model (like the one pictured) or a modern computerized system, share one purpose in common - they must be able to lay down a film of ink with remarkable precision and consistency.

For a typical offset press, one ink tower delivering one of the four primary colors in full color printing lays down an image covering an area approximately 40" x 28". That image is formed by splitting a film of ink 4 microns thick (a tenth the thickness of a human hair) twice (plate to blanket then blanket to paper), while at the same time emulsifying it in a chemical solution (made primarily of water) to a depth of a few molecules. Too much water and the ink washes away. Not enough water and ink starts to print in the background. The ink is carried by approximately 19,250,000 halftone dots averaging in size from 10 to 60 microns. The final film of ink deposited on paper over the whole 1,120 square inch area of the image and is held to a thickness of about 1 micron (one fortieth the thickness of a human hair) with a tolerance of +/- one-tenth of a micron. The positional accuracy of the image is held within one-three hundredths of an inch - about 40 microns. All in one quarter of a second on press.

AM screening - 150 lpi Elliptical Halftone Dot

[click "Play" to view animation - may take a moment to buffer]

Note that the dots are not exactly the same at each percentage. In part, this is to avoid single channel moiré. Also note that in the very light tones (as well as in the darkest tones) as you go through the tones, sometimes there are dots one pixel is size with gaps between them which are then fill with more one pixel sized dots. Then slowly some of the single pixel dots become two pixel dots mixed in with the single pixel ones. This is because a RIP will only image full individual pixels to form a halftone dot. So, in the case of a 2,540 dpi device, each pixel is 10 microns in size (10.6 microns for a 2,400 dpi device). Therefore, if, for example, the the dot diameter needs to be 15 microns in size, since the RIP cannot image a half a pixel to achieve 15 microns, instead the RIP will alternate between 1 pixel dots (10 micron) and 2 pixel dots (20 micron) which results in an effective 15 micron dot average for that tone value.

The elliptical dot shape attempts to avoid the "optical bump" at 50% seen with traditional Euclidean (round/square/round) dots by splitting the point at which dots first touch to 40% and 60% rather than solely at 50%. While it's commonly used, it is not an optimal dot shape in a CtP environment, due to the fact that individual dot shapes are different at each screen angle and that they are directional in nature. When used at low frequencies (


Slur is often confused with doubling as their initial appearance is very similar. However slur is invariably an elongation of the dots in the sheet travel direction. The usual cause of slur is either over or under cylinder packing. Loose blankets, too much plate-to-blanket pressure, too much ink on coated paper, and ink rollers set too hard will also cause slur.

FM Screening - Second Order 20 micron FM/Stochastic Screen

[click "Play" to view animation - may take a moment to buffer]

This is a second order FM screen (Kodak Staccato). In a first order FM screen, dots of the same size are added to simulate darker tones. In a second order FM screen, dots of the same size are added to simulate darker tones – however at a certain tone value no more dots are added. Instead the existing dots simply grow, in one or two directions, in order to simulate darker tones.


Doubling is often confused with slur as both exhibit an elongation of halftone dots. However, slur is usually an elongation in the direction of sheet travel through the press while doubling can be in any direction. Doubling (and slur) often manifest as a problem with the range of tones available in the presswork being compressed and loss of detail, particularly in the shadow areas (a.k.a. muddy halftones). Doubling can be caused by many of the same factors as slur. When the cylinders rotate the halftone dots are not placed in exactly the same position with every revolution. As a result the dots print up as double or multiple images. Doubling between units occurs when a blanket picks up a previously printed ink film. This is known as backtrapping. Examine the dots, or line art graphics, under a loupe to confirm whether the problem is doubling or slur.

Change “survive” to “thrive”

01 Realize that poor economic climates create opportunity.
02 Focus on your core strengths and eliminate weaknesses.
03 Lead against your competition, don’t follow.
04 Raise the bar – set the standard.
05 Treat every job you have as if it were your only job.
06 Talk to new people.
07 Question your business habits and processes.
08 If you can’t do it yourself, get someone who can do it for you.
09 Make bold moves and then tell the world about it.
10 Have fun.

Avoiding "GIGO"

‘GIGO,’ or Garbage In – Garbage Out, is one of the key barriers to the printer achieving an effective, lean, manufacturing process. This is often the result of having to accept client-provided materials that haven’t been created with the technical needs of print production in mind. Why not improve the process by hosting customer training sessions in proper document creation? Keeping your customers current with printing practices will help position you as an indispensable resource for them rather than merely a print provider. A well executed management initiated customer education program will also take the burden off of your individual sales reps to train print buyers and designers.

One effective method is to contract an outside “guru” to provide the instruction. You should charge a fee to cover expenses as well as to emphasize in your customers' minds that you will be providing real value in the sessions. Then, offer to rebate the session fee on the next print order. This way the customer gets valuable training “free” and an incentive to print with you. While you, on the other hand, get better-prepared files as well as improved customer loyalty.

Print buyers don’t buy printing

No print buyer has a need for presswork for the sake of being surrounded by more print. Instead, they see print as a media that fills a communication need more effectively than other, often less expensive and less troublesome methods, such as the Internet. In short they are looking for the unique value that only ink on paper can deliver.

However, if you look at print buyer needs simply in terms of print products and specifications, you may be trying to sell what they are not buying – nor what they value. Instead, try going beyond the specs and look at what your customer is trying to accomplish with their project for themselves, as well as for their customer. Then see if there is a way that you can leverage your print knowledge and techniques to help them better accomplish their print communication goals. Rather than simply parroting printing specs in your quote, acknowledge your uniqueness by translating and describing your technical and service capabilities into differentiating value for their project in your quote.

Thursday, January 19, 2012

Saturday, January 7, 2012

Ink and Paper - a video portrait

Film maker Ben Proudfoot has made a beautiful short documentary about two, next door neighbor shops - one a paper shop and the other a print shop - both struggling to survive.

Aardvark Letterpress
2500 West 7th Street
Los Angeles, CA
(213) 388-2271

McManus & Morgan Paper
2506 West 7th Street
Los Angeles, CA
(213) 387-4433