Saturday, March 24, 2012

Choosing the right print coating

The right coating can help protect the printed piece or add a creative dimension. The results will usually look best on coated paper because the hard, nonporous surface of coated paper holds the coating on the top of the paper rather than have it disappear by being absorbed into the paper. Even when trying to achieve an overall matte effect, a gloss coated sheet is usually the best paper choice and the gloss finish on the paper will provide superior printability. In general, uncoated papers do not benefit very much in appearance from coatings or varnishes, although either will help prevent rubbing in areas of heavy ink coverage. Matte or satin varnishes or coatings are the best choices for uncoated stocks.

Varnishes are applied on press like any other ink and can be tinted to create a special effect. Although gloss and matte varnishes are typically used as spot or overall coatings, they can also be incorporated in the process or spot color inks in order to provide a unique look to the presswork. They can be wet trapped (i.e. printed at the same time as the other inks) or dry trapped (i.e. printed as a second pass through the press after the other inks have dried). Dry trapping provides a superior result but is a more expensive process. Varnishes may yellow with age, however, this is usually not noticeable when the varnish is used over process colors, but it is noticeable when the varnish is applied over unprinted paper. They also require the use of offset spray powder on press to keep the printed sheets from sticking together before the varnish is completely cured. The powder left behind can adversely affect the look and feel of the finished piece.

Gloss varnish: This coating can be applied overall or in spot areas with high precision. A gloss varnish increases the saturation and depth of colors while improving image contrast. It provides good protection against rub-off but some fingerprinting will be apparent on dark or light colors. Because the gloss finish is highly reflective it creates glare on the surface of the print which may impair the readability of text.

Matte varnish: This ink protects the sheet with a non-reflective coating which enhances the readability of text-heavy pages. Using a matte varnish over images tends to flatten and soften them, but it can provide a lush tactile quality to the paper surface. As with a gloss varnish the coating is printed with a litho plate, so it can also be spot applied with high precision. It is more resistant to fingerprinting than a gloss varnish however it will tend to scuff or gloss up with wear. If the presswork is packed for delivery it's a good idea to place blank paper between the printed items to prevent them rubbing against each other and scuffing.

Satin varnish: This coating is created by mixing gloss and matte varnishes together and offers an intermediate level of shine, with good scuff resistance.

Opaque varnish: Adding a small amount of opaque white to a varnish can give it a slight opacity which can help in creating a stronger separation between a gloss and a matte varnish. Adding a slight contamination with silver ink can accomplish the same effect on very dark colors.

Strike-through matte varnish: A litho plate printed varnish that, when overprinted with an overall gloss UV or aqueous coating, will create a visual separation between areas of a press sheet. Gloss/matte effects work best on dark colors, or when enhance by the content of underlying graphics.

Aqueous coating
These water-based coatings are applied using a rubber blanket inline on a special dedicated press unit. among the most commonly used coatings available today and provide good protection from fingerprints and other blemishes. Aqueous coatings are less likely to yellow and are more environmentally friendly than varnishes. They dry faster than varnishes which translates into faster turnaround times on press. They don't require spray powder. Because they seal the ink from the air, they can help prevent metallic inks from tarnishing. Aqueous coatings can cause certain spot colors such as reflex blue, rhodamine, violet, purple, and PMS warm red to change color. Sometimes within a few minutes but also over time - months or even years later. Because the aqueous coating is water-based an typically applied over the entire sheet it is best to use at least an 80# text weight or heavier paper to prevent the paper from curling, distorted, or wrinkled.

Gloss aqueous: Usually applied as an overall coating, gloss aqueous offers better protection than gloss varnish. It is sometimes applied to a spot area however this requires cutting an expensive press blanket. It also results in edges that are not as sharp as a spot varnish and registration that is less precise. The surface dries instantly, making it an excellent choice for short run work-and-turn projects. Aqueous coatings help disguise surface flaws and roughness in the non-print areas of inexpensive papers. The gloss finish improves the apparent saturation of ink but somewhat reduces the readability of text.

Matte aqueous: A scuff resistant matte coating which, as with gloss aqueous, is generally applied overall. And like a matte varnish it will soften and flatten images slightly.

Satin aqueous: A popular compromise between gloss and matte, offers a pleasing sheen and good sheet protection.

SoftTouch aqueous: A proprietary coating that is applied with a special metering roller to create a suede-like texture and extreme matte appearance.

Pencil receptive aqueous: This is a special matte aqueous coating that is designed to be pencil, ink and laser receptive.

Dry erase aqueous coating: An inexpensive high gloss alternative to lamination to make any paper suitable as dry erase marker surface.

Primer aqueous: A coating that is applied before lamination, or to difficult substrates to make them ink receptive.

UV Coatings
UV coatings are applied inline by printers or offline by finishers or converters. They are applied as a liquid, using a roller, screen or blanket, and then exposed to ultraviolet light to polymerize and harden the coating. Like aqueous coatings, UV coatings can cause certain spot colors to shift in hue. Some UV coatings may have a strong odor.

Gloss UV: Creates the highest printable overall gloss coating. Depending on the printer's equipment it can be applied to spot areas.

Matte UV: Depending on the printer's equipment it can be applied overall or just to spot areas. It is prone to fingerprinting.

Pearlescent UV: These gloss coatings include miniscule metal flecks in red, blue or silver, giving a pearlescent appearance.

Orange peel UV: A slightly raised, textured finish, gives this coating a unique tactile and visual quality that is similar in appearance to thermography.

Friday, March 16, 2012

The Wayback View - Printing the London Telephone Directory - 1937

"The Telephone - A Sound Investment" promotional postage stamp canceling mark.

In the 1930s, telephones were still not in general use, so in 1937 the British GPO (General Post Office) Film Unit produced a short film on the production, and value, of the London Telephone Directory. The film "Book Bargain" was directed by Oscar winning Canadian film director and animator Norman McLaren.

Sunday, March 11, 2012

Inks beyond CMYK, Hi-Fi, and Pantone - the world of effects pigments

Printers and their customers are always looking for new ways to add value and a creative spin to print. When conventional CMYK, Hi-Fi, and Pantone spot colors just don't have the impact - it's time to look at the options available with effects pigments.

Here is a run down of the most popular effects ink pigments. Savvy printers will pretest and, based on their understanding and relationship with their customers, make them aware of the creative opportunities these inks provide.

Photochromic inks
Arguably one of the most popular of the effects inks. Photochromic ink undergoes a reversible color change when exposed to UV light. The color change is immediate and reverts to its original color or becomes colorless when the light source is removed. This ink is available in wet or dry offset and flexographic printing.

Austria Solar's 2011 annual report uses photochromic inks to parallel the company's business. It ships in a foil package. Open it under indoor light and all you’ll see is an embossed cover followed by blank pages. However when exposed to the sun the photochromatic inks react and the content is revealed. The report is the creation of agency Serviceplan and Creative Director Cosimo Möller.

Photochromic inks are available in colorless-to-color and color-to-color formulations.
Photochromic ink viewed under office lighting.

Photochromic ink viewed under sun light.

Thermochromic inks
Thermochromic inks are temperature-activated. When rubbed, held in the hand, or exposed to differing temperatures the ink changes from a colorless state or to another color and quickly reverts to its original color.

As with photochromic inks, thermochromic inks are available in colorless-to-color and color-to-color formulations. The temperature when the color change occurs can be predetermined - e.g. color appears at 72°F and becomes colorless at 90°F or color appears at 81°F and becomes colorless at 90°F.

This ink is activated by water, not sunlight or heat. A white hydrochromic ink just looks like white ink. When water is applied, it disappears and the image behind it appears. When the water dries, the image goes back to white.

UV Fluorescent
These inks are normally invisible as printed but fluoresce under UV light. There are two types; single long wavelength (360 nm) and dual which fluoresces one color under short wavelength UV (250 nm) and a different color under log wavelength UV (360 nm). Typical UV fluorescent color inks include yellow, green, blue, orange, and red. These inks are often used in banknote printing. This ink is available for wet or dry offset, flexographic and gravure printing.

Optically Variable Ink
This ink contains minute flakes of metallic film which, when viewed at different angles, morphs from one color to another very dramatically. This ink needs to be printed with a fairly heavy weight to get the best results which makes the ink feel almost embossed on the substrate. The ink are very expensive and therefore is usually printed in small areas. The most common color changes are brown to green (and vice versa) as well as red to purple. It is typically used for passports and driver's licenses.

Bleeding ink prints in black but when exposed to any aqueous solution it will produce a red stain - even when touched with just a wet finger. This ink is only available for use with dry offset printing.

Fugitive Ink (water based)

Fugitive ink works similarly to bleeding ink since when exposed to water or an aqueous solution the ink runs. These, also, will be found on checks and if you are to wet your finger with saliva and wipe across the background, you would see the ink smudge.

Coin Reactive
The image printed from this ink is white or transparent. The image is revealed when the edge of a coin is rubbed over the ink. Coin reactive ink cannot be scanned or copied.

Erasable ink is used on the background of a document. If an eraser is rubbed on it the ink rubs off in that area. The ink also reacts in the same manner as solvent/chemical reactive inks do. Erasable inks are typically used on scenic or pantograph backgrounds on checks and certificates. This ink should not be used for documents that will go through a laser printer.

Iridescent ink is a translucent pearlescent ink which, when viewed at different angles, creates a subtle change of iridescent hues. It is available in blue, red, green, gold, and silver.

Metameric Pairs
Metameric pairs are two inks that appear similar in color under one set of light conditions but are visibly different under another set.

Puff Ink
Puff ink rises and expands ("puffs") when exposed to a heat source.

Glow in the Dark Ink
This ink radiates a bright light green color after being exposed to bright light and then placed in a relatively dark environment.

Penetrating Ink/Indelible Ink
Penetrating inks contain a penetrating red dye that goes into the fibers of the paper and will show through to the back of the document. Penetrating inks are commonly used on the arabic and MICR numbering of negotiable documents to deter forgers from trying to scrape the number off from the document. If the number is scraped off the red stain remains on the document. Penetrating inks are available for letter press or wet offset printing.

Friday, March 2, 2012

Drupa 2012 - With a song in my heart

Like any major trade show - and the 2012 edition of Drupa certainly ranks as such - a stirring theme song is used to get everyone excited and motivated to attend.

Drupa's 2012 song is: "Get Ready to Succeed"

Drupa 2012 has even spawned a tribute "The Magic Of Drupa" by Alex Kunst and Laurel Brunner.

The previous show - Drupa 2008 had a similar dance-based beat with more words than you could imagine would fit into the tune of: "One World One Drupa"

To get an idea of how far the industry has come, one has only to listen to the painful theme from Drupa 1986:

Drupa 2012 takes place May 3 - 16, 2012 in the Düsseldorf Fairgrounds. If you're in the graphic arts you owe it to yourself to attend at least one Drupa in your lifetime.