Color-Matching Ink Systems from the Ground Up
Discover what types of mixing systems are available, how to use them, and where you can get them.
Color-matching ink systems allow garment screen printers to create simulations of Pantone colors and, with custom-mixing capabilities, replicate a variety of customer-required colors and color palettes. These tools always seem to be a hot topic because they help screen printers manage what would otherwise be a difficult task. Printers who are prepared to work with color-matching ink systems will find that a good system can streamline the whole ink department. But getting to this point requires the proper setup of a color-matching area and the acquisition of the right equipment. The next steps involve using the system to accurately match colors and reassess the process when things don't look right.
This article will discuss ways to set up an effective mixing space, properly use a color-matching ink system, and troubleshoot the ink-mixing process. Let's start with a review of color terminology and attributes for ink mixing and matching.
How light creates the color in your inks
Human eyes are amazingly sensitive instruments. They can perceive millions of colors. Fortunately, you'll never have to match more than a fraction of these colors with inks! Most printers can get the job done with a group of inks in each major primary and secondary color (red, blue, yellow, orange, green, purple) and then mix the rest as needed.
An ink's composition is indicative of how it mixes to create additional colors. Inks comprise pigments suspended in clear or semi-opaque bases with other agents, depending on the type of ink in use (plastisol, water-based, etc). Inks don't actually produce color. The pigments in the ink reflect a wavelength of colored light while absorbing the rest. If all of the color is reflected it becomes white ink; if all wavelengths are trapped, then the ink appears black. A red ink absorbs all colors except for the red light.
To be even more specific, the pigment suspended in the base of the ink does the coloring. The reason this distinction is important is because there is always a quality to the pigment load itself, and the way it is distributed in the base will affect the ink's interaction with other inks. The attributes of ink's pigment load (Figure 1) can be categorized as follows:
• Hue This characteristic is where we get the name of the ink (red, blue, etc.). It is defined by the wavelength of light that the pigment reflects.
• Saturation This refers to the purity of the color or how sharp or dull it appears (sometimes called chroma).
• Brightness This quality of the ink, also referred to as value, relates to the ink's shade or tint (darkness or lightness).
Two additional properties of the inks directly affect the hue and the way that the color is presented. These properties include
• Finish The quality in the ink that defines how glossy or matte the final surface of the cured will appear. Matte-finish colors often appear much lighter than gloss finishes after curing, and achieving deeply saturated hues can be tricky. These are some the reasons that you should cure test your matched colors and not just view them in the can.
• Opacity This can affect several areas in presentation. Ink that is considered a high-opacity (or HO) formulation doesn't allow light to pass through a finished layer. HO ink tends to be more of a matte finish and flatter in color. The opposite of HO ink transparent ink. Transparent inks tend to have a glossier finish and be deeper in color. Most four-color-process inks (CMYK) are very transparent so they can produce the widest variety of different hues when blended. Opacity also can affect the coloration of an ink by influencing the way the printed surface or other inks underneath it change hue or value.
These factors combine to form the visible color that is reflected from the surface of ink. The more you understand and control these different attributes, the more consistent and reliable the ink-mixing process will be. Now let's look at the mixing environment.
Setting up a good mixing environment
The volume of ink you typically need to mix will influence how you need to set up the mixing environment. If a shop needs a large quantity of ink mixed for long print runs, the whole environment will be significantly different than that of a smaller-volume shop. The larger printer would be prudent to investigate some of the larger ink manufacturers' options in ink-mixing systems and use their tools and concepts to help set up the most efficient solution for mixing and matching lots of ink. A smaller printer that is experiencing growth and higher ink-mixing demands is also a good candidate for a color-matching system.
It's important to investigate the specific system that you decide you want to use so that you can set up your environment appropriately for that system's style of ink mixing.
The basics of setting up an ink-mixing environment (Figure 2) are as follows:
1. Set aside a designated area with enough space to store 20 or so inks in separate containers that are within easy reach. Try to prevent a lot of bending over when containers need to be handled. Much of what we call environmental efficiency relates to how many steps are necessary to do a mixing task. A large, solid counter space that is resistant to solvents can help streamline the workflow.
2. Check the lighting in the mixing area! The best lighting setup provides even illumination in a day-light color temperture. The press area should be lit by a similar source to ensure consistency in samples and strike-offs.
3. Determine which method best suits your shop and ink system for getting ink in and out of the containers. Some printers will joke about this idea (just dump it out, right?), but it is easily one of the largest time wasters in the ink department. Each ink spill takes time to clean, and spending more than five minutes to mix a gallon of ink costs money. Manual or automatic pumps may not always be the best options—the systems can vary dramatically, and some pumps can take five times longer than a spatula to move ink. A combination approach is often the best, with pumps reserved for 5-gal or drum containers and the simple stainless-steel spatulas working the fastest for the gallon buckets. Time the whole process and trim any wasted time possible without spills.
4. Get a good scale with a stainless-steel surface. A high-quality scale will resolve tenths of a gram and still give a consistent reading when the ink isn't perfectly centered on the scale.
5. If possible, acquire a used or refurbished computer to run the software that accompanies most color-matching ink systems. Keep the computer at the ink station. Simple covers for the keyboard and mouse protect these items from solvents and inks. Just make sure the computer is powerful enough to run the operating system the software requires.
6. Acquire a variety of mixing buckets (gallon, quart, etc.) with matching lids. Keep some permanent markers and labels close at hand with the spare buckets.
7. Check with garment suppliers for fabric squares that can be used for strike-offs and tests. The material should be the same as the shirts that you decorate. Pellons or stiff fabric simulations don't allow the same absorption as shirt material and can cause color shifts. They can be fine for a quick test, but so is a piece of white cardboard. Old shirts are fine, but sometimes that isn't the smartest use of a couple of bucks (vs. tax write-offs for donations or discount sales).
Working with a color-matching system
Let's look at using a color-matching system to mix some Pantone color simulations. Keep in mind that what you'll produce for garment screen printing is never truly a match of a Pantone color, because Pantone colors are based on offset inks printed on paper. The safer term to use is color simulation. Some of the more saturated hues in the Pantone book are very difficult (if not impossible) to mix for screen printing.
Always educate the customer, and be prepared for some downtime should the color need to be adjusted on press. One industry trick is to have an additional screen of the same color that will be flashed and doubled up when printed on a white underbase to really give a deep, saturated color on a dark garment. This is where the art comes into the screen-printing effort, and it is more important for the color to look good with the artwork on the shirt than for it to be an exact match. Customers who want a perfect match to a paper sample need to wear paper shirts.
Color-matching systems generally fall into two categories: a finished ink system where two or more inks from a set of 12-15 blending inks are mixed together to form a finished color, and a component system where pigment concentrates are mixed in various combinations with a semi-opaque base to form a finished ink of a specific color. The component system may offer a slight advantage in terms of control and flexibility, while the finished ink systems are super simple and tend to be more opaque (and moderately brighter). Finished inks tend to be a better choice for those who specialize in producing really bright prints on dark shirts (e.g., black, purple) because of the inks' higher opacity and brightness.
The biggest decision you face in selecting which ink system to use is often more about service than product. The supplier that provides the most reliable service and has good plans for contingencies (quick shipping, replacement of bad ink, equipment service, and effective communication/ordering) will often be the better choice.
Software for color matching is another consideration. The system should provide some of the following:
• formulas for Pantone color simulations with a breakdown of components that will adjust depending on the amount of ink needed
• ability to add custom mixes and adjusted Pantone mixes to the software database
• formulas for a custom color palette of commonly used colors
• ability to estimate the needed ink for a specific job through a breakdown of ink weight per shirt (weigh the shirt before and after printing and then input this into the software with the screen mesh for an estimate of the amount of ink needed)
• average cost of print in ink per shirt
• a place in the database for storing notes on a specific mix.
Mixing a Pantone color simulation in a color-matching system is relatively simple. Just open up the software and select the color and quantity of ink needed. Next, add the inks or pigments and base together in the amounts shown, then fully mix them in an appropriate bucket. If you don't have automatic mixing equipment, a useful tool is a hand-held drill with a mixing blade that will work at slower RPMs. This will allow you to fully mix inks quickly and eliminate the physical exertion.
The next step is to compare the final ink in the bucket to the color sample that you're trying to match (Figure 3). If the result appears to be very close to the sample color, it is a good idea to do a quick drawdown (actual print on T-shirt fabric) of the color and send it through the dryer to insure that the screen mesh and the curing process don't alter the color significantly from the wet version. Useful items to have for quick drawdowns include small screens, about 10 x 10 in., of different meshes and little squeegees of different durometers that can be quickly laid onto fabric samples and used to print color swatches. If all works as planned, the colors will look the way they should—but this isn't always the case.
What happens when the Pantone color that you mixed doesn't accurately simulate the color in the sample? Start with the basics. View the color in the proper lighting and try to determine whether the current mix was properly prepared. A common problem, especially when color matching with smaller amounts of inks, stems from the use of a really strong pigment or ink. A tiny amount of black or white, often just a drop, will totally alter the color of an ink.
First, double check the current mix and resample it to rule out a mixing error. If the next mix exhibits the same problem, then look at the color and determine whether it's off in value, hue, or saturation. Ink that is off in hue is the easiest to fix. A small amount of ink of the right hue can bump the color in the right direction. Just look carefully at the hue and determine which color would correct it. Make small additions to the mix to slowly move the color to the correct level. Remember that small corrections are always better in ink mixing. If you overshoot the target with a big change, you'll have to scrap the ink.
Ink that appears to be off in value or saturation is more difficult to adjust. Sometimes your best bet is to start over with a different set of colors when you note a dramatic difference in value in the mixed ink. Only rarely does the addition of black or white change shade or tint without damaging saturation (colors will appear washed out or really dirty, rather than deeper or lighter).
Finally, using a Pantone mix that appears slightly deeper or richer than the color needed, and slowly adding a lighter color or white to back it down to a close simulation, can be a good solution when dealing with a really bizarre hue, a match to a fabric sample, or an item that has different reflective properties from the printed ink.
Mix and match
The proper use of a color-matching system can save the average screen printer a significant amount of time and trouble. You just have to find the right system—one that matches the type of work that you commonly handle—and identify a supplier that can service you well. Efficiency results from accuracy and good recordkeeping in the ink-mixing area, as well as proper testing as part of the matching process for any job. By sticking to this organized procedure for color matching, you'll be rewarded with colors that are on target and presses that can roll.
About the author
Thomas Trimingham is an award-winning art director, illustrator, and separator who has more than 16 years of experience in the screen-printing industry. He can be reached at firstname.lastname@example.org.