Thursday, August 16, 2012

The eternal conflict - ink/water balance - the tale of the tones

An AM/XM halftone screen has a builty-in conflicting ink/water balance requirement on press. The highlight dot and quarter tone range from 1-35% requires minimal water and maximum ink in order to prevent those dots from being washed away. The three-quarter tone range from 65-99% requires the opposite - a larger volume of water in order to prevent the shadow dots from filling in and disappearing. On the other hand, the mid-tone range from 35-65% is more of a balance between ink and water.

Halftone dots and the tones range they represent are affected differently by the condition of the ink on press - assuming of course, that the plate, press, and chemistry are set up correctly. Unfortunately, if the press operator attempts to fix tone reproduction in some areas, that built-in difference in ink/water requirement can exaggerate the inherent conflict and cause problems in other parts of the tone range.

1 - 1-35% This tone range is primarily affected by the body/viscosity of the ink. If the body is too soft the highlight area will print too full which may cause the press operator to decrease solid ink density in order to reduce the dot size. Alternatively the fountain solution may over-emulsify this tone range causing poor ink transfer and loss of highlight detail. If the ink body is too heavy the dot may print too sharp causing the press operator to increase the density or blanket pressure.

2 - 35-65% This tone range is primarily affected by the strength (pigment load) of the ink. If the ink is too weak the press operator will increase solid ink density which will cause increased dot gain and result in presswork that appears too full. If the ink is too strong the midtones may print too light. Also, the strength of the ink also impacts how well the inks trap, which in turn affects the color gamut the press should be able to achieve. Varying the strength and stiffness of the ink to achieve good tone reproduction in presswork is a method press operators, who don't have good communication with prepress, often employ. It's almost always better to use tone reproduction curves applied in plate imaging than to modify inks.

3 - 65-95% This tone range is most strongly affected by mechanically induced dot gain or chemistry issues i.e. (poor ink water balance). If the tone range from 1-65% is evenly balanced then excessive gain in the shadow tones is usually caused by running excessive water, too much blanket pressure, and/or mechanical slur.

Thursday, August 9, 2012

Paper - from another most unusual and environmentally friendly source

Paper made from poopPlant fibers (typically from trees) are the usual base material used in making pulp for paper production. However those plant fibers don't have to come unprocessed directly from the plant. The fibers can actually be gathered after being processed by certain animals and delivered for paper-making in their poop.

Paper products can be made from the poop of a variety of different fiber-eating herbivores including elephants, cows, horses, moose, pandas, and donkeys. These animals eat lots of vegetation everyday and they are prolific poopers. Since the digestive systems of these animals don’t break down the vegetation very well, their poop contains plenty of fiber even after their meal is consumed. They are basicaly doing the first stage of any paper making process – getting the fibers. Elephants, for example, can eat upwards of 250kg per day of fiber-filled meals with much of that passing through their systems largely intact. It is estimated that one elephant can produce enough poop to make about 115 sheets of paper per day.

From poop to paper

Although the source may be different, the process of making paper is not that different from making it from conventionally acquired fibers.
First, the poop is collected, then rinsed and boiled to a pulp. The solution is then blended or spun to soften and cut the fibers. Other things such as dye and/or other fibrous materials may be added to give the solution the proper consistency.
The slurry is then sifted onto rectangular sieves and allowed to dry. When dry, the thin layer of plant fibers is peeled off the sieve and made into raw sheets and rolls of paper.

Using paper made from poop is a fantastic example of sustainable and recycling practices and solutions to our environmental challenges.