Under normal circumstances, the printing process is stable and consistent in color. Unfortunately, printing operations waste ink, substrates, and printing time trying to achieve the correct color. Despite technological advancements making color accuracy easier to achieve, variables that affect color still exist. In this three-part series, we will share over twenty reasons why your colors may be off in print. We will first look at potential issues affecting color measurement instruments and substrates.

0°/45° spectrophotometers (like our eXact 2) are popular in print and packaging applications. However, if you are measuring reflective materials such as polyethylene or foil balloons, or printing with metallic inks, you should use a spherical geometry spectrophotometer like the Ci64.

Reflective surfaces are challenging because the influence of gloss actually alters the color appearance of the sample. 0°/45° spectrophotometers exclude gloss to mimic how a human observer would see the sample. Therefore, a 0°/45° measurement on foil may not match what the naked eye sees. Using a sphere instrument like the Ci64 allows for the inclusion or exclusion of gloss in different applications, making it match what the human eye sees.

Poorly calibrated instruments, especially those that have been dropped, can lead to poor color readings in print. If your instrument is reading incorrectly and you haven’t checked the calibration carefully, your press operator may end up adjusting the ink to something different so the software shows it is correct.

This common problem is easily solved with proper equipment maintenance. Calibrate regularly, at least before each operator change. If your instrument fails calibration or your measurements are far off, it may need servicing. Contact us for spectrophotometer maintenance.

Ensure you are using the same light source and observer settings to read and evaluate samples as your standards. Most print facilities check color under D65/10° midday sun or D50/2° horizon sun, but sometimes clients will specify their unique tolerances ahead of time. Be sure to check this before you begin work.

Delta E CMC has been a popular choice since its development in 1988, but Delta E 2000 is gaining popularity among some of the largest printer buyers. This newer tolerance calculation is more forgiving when reading color samples. Some workflows require you to switch between Delta E calculations for different clients. It’s easy to forget in the heat of preparing work.

Choose the tolerance formula that best suits your needs. If your client specifies a spot color and requires a specific delta E match, ask which formula so you can use it. If you don’t choose the correct one, you may fail some jobs that should pass, or your client may reject jobs you think are acceptable.

This area represents all colors considered acceptable within a ∆E of 1.

The backing material placed under your print sample is very important. Many samples are not completely opaque, so the instrument can pick up color data from the background and skew the measurement. Using a backing ensures the instrument only reads the color data you want to capture. A stainless steel or wood table is not a good backing choice. Always use the same black or white backing for consistent readings.

The best option is to purchase backing material that meets ISO standards. If you choose to select your own backing material, ensure they are all from the same batch and consistent across the measurement area. Remember, if they don’t meet ISO standards, you need to use the same material from prepress to press side.

This is a problem we often encounter. Clients send L*a*b* values for matching but don’t include the complete reflectance dataset recorded when the color was measured. Even if the press operator manually inputs the L*a*b* values correctly as the color standard, the final color may still be incorrect.

It’s best to use a color measurement device to read your standards into the software and then export them as a .mif or .cxf file. These files can easily be emailed to clients to ensure everyone is using the same color standard, including reflectance data.

To get consistent readings on paper containing fluorescent whitening agents and achieve agreement in the viewing booth, most measurement modes now use M1. Using different measurement modes can lead to workflow mismatches depending on the paper used and the specifications or targets provided. It’s important to know that some standards may have been made using one of these inputs, regardless of whether your operation has switched. Pay attention to these M settings coordinating with your operation. You may need to re-input many standards when you make a switch.

Inconsistent color will result if only one operator performs these steps. You need to document everything and communicate it to everyone involved in the workflow. Standard Operating Procedures (SOPs) provide flowcharts, help troubleshoot problems, and make training new employees easier. When properly developed and implemented, SOPs also ensure everyone operates the spectrophotometer the same way, regardless of shift or location.