March 2024

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.

UV curable ink is cured and adhered to the media or substrate by UV radiation. The print is already dried when it comes out of the press, allowing a short deliver request to be met. This also is beneficial for printing on non-absorbent materials, including plastic, which Shapco can print on.

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 six months 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.

UV Ink has a shelf life of a year, otherwise it starts to harden in the can.

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 Shapco

Shapco offers three process color ink types: Soy ink, UV ink and standard Eco friendly 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.

At Shapco, our standard house ink represents the very latest in ink technology; mineral oil and cobalt free. It’s the leading ink series for those concerned with environment. 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. Our UV ink is Green-Eco friendly printing ink.

VOC’s information:

UV Ink - Shapco’s is 0% VOC’s

House Ink - Shapco’s is 1% VOC’s

Soy Ink - Due to low demand, this ink has to be special ordered. (Must have at least 20% soy oit to use soy logo.) Black 3%, Cyan 3%, Magenta 20.3%, Yellow 17.9%

* All VOCs listed use EPA Method 24

Reducing our ‘enviro footprint’ even more

Here are some additional environmentally-friendly efforts we are implementing at Shapco:

• All of our Waste paper corrugated, and plastic are sent to a recycling company weekly. Also all waste ink is collected and sent out to be recycled as well. As are our press rags spun out to remove any liquid chemicals, then that liquid is sent to be recycled.

• 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 UV inks, Coatings, Varnishes, metallics, pastels and neon’s

• 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 and Substrate)

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.

UV inks are another option. It can be used to print on a non-porous substrate. It has great hold out for color on an uncoated sheet and keeps it’s brilliance of color. In addition, has a sharper dot for more detail.

Coatings, there are a wide range of coatings available today, from High gloss UV coating, to a gloss/dull effect. Also, different textures and looks. Aqueous is available in gloss, dull, satin, soft touch, pearl essence. Varnishes can offer a variety of different effects as well. Gloss, dull, satin or a combination of both. For more information on coatings, go to my Creative Coatings link

Shapco can also provide you with a “drawdown” of ink onto different specified paper stocks, with or without coatings, so you can really visualize how the ink color will appear once printed. We do this all in house as well.

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”.

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 and Substrate)

(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

Creative Coating Techniques

Picking the Right Paper and Substrate

Press Check Tips

UV Burn

Duotones-Tritones-Quadtones

Paper Mill Tour - Coated

Paper Mill Tour - Uncoated

Before we go...