Five Tips for Using a Colorimeter in Printing

In an ideal situation, we would simply load ink into the press and run the job. Unfortunately, many variables affect color, and print production often wastes materials and time on adjustments.

A colorimeter makes color measurement easier, but variables remain. This guide explains five factors that can affect color measurement during printing.

1. Use the correct substrate

The substrate placed beneath a printed sample is important because it ensures that the colorimeter reads only the color you intend to measure. For transparent, translucent, or thin samples, use the same backing material and setup used for the standard, and keep them consistent between measurements.

2. Keep the colorimeter in good working condition and use it correctly

Poor calibration, especially on an instrument that has been dropped, can lead to inaccurate color readings during printing. If the colorimeter does not read correctly and its calibration is not carefully checked, the measurement may be affected and color differences may result.

Pay attention to calibration and verify that the instrument is stable. If calibration fails or readings vary substantially, the instrument may need servicing. WINSHOP provides colorimeter repair and quality services.

3. Choose an instrument with the right geometry

One of the most important considerations when selecting a spectrophotometer is the type of surface you will measure. The three main types are 0/45° instruments, integrating-sphere instruments, and multi-angle spectrophotometers.

Although 0/45° instruments are commonly used for printing and packaging, they are not suitable for highly reflective materials such as metallized foil balloons. Light from the instrument can reflect away at extreme angles because of the embossed surface texture. Many printers still use 500 Series or eXact instruments for metallic inks, but the results may be limited. The instrument can produce a reading, yet the data may be inconsistent depending on the reflectance of the metallic texture. Integrating-sphere geometry is needed for these applications.

4. Use the correct filter setting

More printers are setting their instruments to M1 to account for optical brightening agents found in paper. If your operation has not made this change, you still need to pay attention to the M measurement condition, because some standards may have been entered using M0, M1, M2, or M3.

Make sure these M settings match your workflow. If you switch conditions, you may need to re-enter many of your standards.

5. Pay attention to illuminant settings

In print production, color is commonly checked under D65 illumination with a 10° observer (often described as midday sunlight), or under D50 illumination with a 2° observer (often described as horizon sunlight). When choosing an illuminant and observer angle, you need to know how the standard and sample were measured. The sample must be measured using the same method as the standard. Some customers may also specify a particular tolerance in advance.