Everything you wanted to know about ink (but were afraid to ask)
This issue of TK’s Korner will focus on the wonderful world of ink — its fundamental characteristics and its effect on different papers. Ink and paper choices can either ‘make or break’ the time and effort that is put into your printed designs. Some questions for consideration include:
1. How easily readable should the type be?
2. What is your desired intention for images (photos and art)?
Do you want them to pop off the page?
3. What special techniques do you have in mind and how can you
get the desired effects?
4. Will the printed piece produce the results you want?
Printing ink basics
There are hundreds, if not thousands, of different inks being used by commercial printers today. All inks share the same three basic ingredients:
Colorants (in liquid dyes or dry pigments) give ink its color.
Carrier vehicle (such as petroleum or vegetable oils, solvents or water) carries the pigment.
Additives provide the desired performance characteristics, such as:
DRIERS help the ink dry more quickly.
WAXES help the printed surface resist scuffing and reduces set-off (the transfer of the image from the front of one sheet to the back of another).
OTHER ADDITIVES allow the pigments to cover more area, protect against drying too quickly and improves the way the ink bonds with the paper or substrate.
Characteristics of printing ink
Viscosity is the degree to which the ink resists flowing. This can change under the heat and pressure of the printing process, especially during long runs or at high speeds.
Body is the overall consistency, and can range from soft and pliable to stiff and rigid.
Opacity is the degree to which it allows the whiteness or color of the stock to be visible.
Light Fastness or Color Permanency is the ink’s ability to resist a shift in color caused by UV radiation or heat. This type of ink is primarily used for in-store signage that is exposed to strong, constant lighting or significant sunlight.
Various types of printing inks
A tour of an manufacturing plant can show you how ink is made.
(See photos from the tour).
Listed below are types of inks produced by the manufacturing plant:
Oil-based Inks are used for web heat set, newsprint and offset (for both commercial and packaging industries.)
Water-based Inks are used for flexo printing.
Solvent-based Inks are used for flexo, gravure and news injector.
The shelf life of ink
Regular Ink has a shelf life of three years. After that time, it can start to body up and become tackier. The driers can also become weakened and cause some drying problems.
Metallic Ink has a shelf life of two years and is dependent on the amount of metallic pigment that it is made with. Pigment oxidation, where the ink color starts to tarnish and the tack or viscosity of the ink changes, can also occur with metallics.
What about environmentally-friendly (eco) inks?
The difference between conventional ink and environmentally-friendly (eco) ink comes down to the ‘carrier vehicle’ used in the formula. Traditional ink has more petroleum products and eco inks use more vegetable oils for the carrier. The easiest, most reliable way to determine this is by the volatile organic compounds (VOCs) that are released into the air. VOCs are from petroleum products, so the higher the VOCs, the more petroleum there is in the ink formula. There are different ways to measure VOCs, so the same standard needs to be used if comparing inks. The EPA Method 24 is the most common standard method used.
Inks that we offer at Sexton Printing
Sexton Printing offers three process color ink types: Soy ink, Agri ink and standard house ink.
Soy ink is the most recognized name when it comes to eco ink. But while it makes a good newspaper ink, (about 90% of the daily newspapers use it,) it’s not the best eco choice as a sheetfed ink. The problem with soy oil is that it can take on water which can cause drying problems. Today’s sheetfed soy inks set and dry well, but there may be more petroleum products to help them dry, causing the overall VOCs to be a bit higher.
Agri ink, on the other hand, can use less soy oil (20% is required to use the soy logo) along with other vegetable oils such as linseed, corn, canola, etc. to create an ink that will set and dry better with less VOCs.
At Sexton, our standard house ink is a high vegetable oil ink, but it is not as eco-friendly as our Agri ink. We do offer a soy process ink for those clients that are absolutely required to use the soy logo, even though it’s our least eco-friendly ink.
Standard House Ink VOCs*
Black 15%, Cyan 15%, Magenta 15%, Yellow 15%
Soy Ink VOCs*
Due to low demand, this ink has to be special ordered. (Must have at least 20% soy oil to use soy logo.)
Black 16%, Cyan 16.7%, Magenta 20.3%, Yellow 17.9%
Agri Ink VOCs*
Black 3%, Cyan 3%, Magenta 3%, Yellow 3%
* All VOCs listed use EPA Method 24
Reducing our ‘enviro footprint’ even more
Here are some additional environmentally-friendly efforts we are implementing at Sexton Printing:
? We installed a solvent recovery system in our pressroom that distills the dirty press wash and turns it back into reusable clean press wash. This improvement means we went from 72 drums (55 gallons each) of waste wash per year to just three drums for the entire year! We now use 60% recycled and 40% virgin solvent.
? We improved our printing plates. We now use the Agfa Graphics Azura TS chemistry-free platemaking system. The new computer-to-plate system offers consistent and reliable production without compromises on press. It delivers razor-sharp image definition and holds up to 2%–98% screen tints at 200 lines per inch. In addition, a dedicated cleaning unit uses gum to finish and clean the plates, with absolutely no chemical processing involved. This creates a healthier work environment and annual savings of approximately 150,000 gallons of water, previously required with older equipment.
Different ink types can produce desired effects
The effort that you put into your printed designs can be enhanced with ink choices beyond the four process colors (cyan, magenta, yellow and black), particularly specialty inks such as:
? Spot-color inks, including metallics, pastels and neons
? Special-match inks (or custom inks)
Spot-color metallic inks contain metallic particles such as bronze or aluminum. The metallic particles make the inks opaque, rather than transparent. This is why you can notice the trapping of a metallic over another ink.
Metallic particles stand ‘on end’ when printing then lay flat when dry to show their actual color. This is why metallics tend to look different during a press check rather than the swatch book. (Note: there are techniques one can use while on press to try and get the true color to come forth.)
It is also important to note that screening metallics can cause concerns and not yield the effect you are trying to achieve. Because metallics are opaque, each metallic has a different ‘break point’ before a screen of it will plug up. As a result of this, you may not be able to run the metallic as heavy as you want or need. Consult with me first in order to have a better understanding on what can be accomplished in this area.
Additionally, because the metal particles cannot be ground as fine as conventional pigments, they can often cause problems on press. Metallics require a different ‘ink-water balance’ than conventional inks and also may require extra drying time. Post-printing finishing, such as UV coatings, film lamination, foil stamping and some laser applications, can cause issues with metallics. When using an Aqueous or UV coating, you’ll need to be aware of UV Burn. (Learn more about UV Burn here: UV Burn)
Metallics are very soft and susceptible to rub-off and tarnishing, which can necessitate the use of varnishes or coatings. Unfortunately, coatings tend to soften or negate the metallic effect.
Lastly, the type of paper you use with metallics is extremely important. (Learn more about choosing the right paper here: Picking the Right Paper)
Spot-color Pastel Inks are an excellent choice whenever softness or subtlety is desired in your printed piece. They are especially effective when you want a large area of smooth, solid pastel color without the appearance of screened process ink or when you want extremely subtle graphic elements printed without screening back color.
Spot-color Neon Inks are extremely effective when you want immediate and significant “pop” in your printed piece. Neon inks are super vibrant and demand attention when used in both large or small areas. When positioned next to rich black, neon inks provide amazing contrast!
Special-match (custom) Inks are uniquely formulated and are not correlated to a specific Pantone color. They can be formulated to be one-of-a-kind or to match an existing color that is not Pantone. A company can consistently use a custom ink color in their materials to be completely differentiated from others. Special Match inks also can be formulated so an ink color on a special substrate can be adjusted in order to match a previous standard on a different substrate.
An ink company can also provide you with a “draw down” of ink onto different specified paper stocks, with or without coatings, so you can really visualize how the ink color will appear once printed.
Keep in mind that ink can vary by “lots” just interior home wall paint. To ensure color continuity across multiple pieces, you may wish to order enough ink for all pieces upfront and from the same “lot”.
Just ask! Sexton can provide you with color proofs, prints or draw downs onto various substrates so you can visualize how the color will appear on a specific substrate when printed.
Ink on press. Ink on paper.
The ink rollers spread the inks onto the imaged areas of the plate, while other rollers apply water to repel the oily ink to the non-image areas of the plate. Each plate then transfers the ink to a rubber blanket that in turn transfers the ink to the paper (like a squeegee effect.)
The type and color of the paper stock can have a major impact on color reproduction. For instance, printing on a coated versus an uncoated stock will yield very different results. There are even different ink swatch books for coated and uncoated papers.
(Learn more about choosing the right paper here: Picking the Right Paper)
(Some of this info was obtained from Flint Ink, StoraEnso’s “This is Ed #9, Understanding Ink” and of course my own past experiences.)
Check out more relevant information from past issues
Before we go...
If you have a production issue not discussed above that you would like me to address, or a project that needs to be looked at, please give me a call or send me an email.
As always, I will do whatever it takes to ensure you receive the best value for every marketing dollar you invest.
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Take care and have a great day!
Successfully,
Tom Kubinski
Printing Consultant Who Helps You Make Good Impressions
Direct: (651) 255-1225
Cell: (612) 760-3700