With the aid of sensors and computers, inks can be managed to correctly match desired colors and reused for different jobs, which improves quality and reduces waste.

Spectrophotometers measure the colors reflected off a printed sample. These colors are measured, categorized, and compared with an accepted standard like a color swatch. By recording the press operating parameters when the sample is produced and knowing how the press performs with different parameters, it is possible to forecast the correct parameters to produce a different color sample.

Color matching software can work with a database of color characteristics from various virgin and previously-used ink colors. Each time excess ink is returned from the press, its color characteristics can be added to the database. The software can then select the best combination of virgin and reused ink to match a color in a new job. Any required additions to the reused ink can also be forecast to maintain ink quality.

Reused ink can be prioritized over virgin ink, making maximum use of purchased inks. By reusing inks with this process, one flexographic label manufacturer has reduced ink inventories by 40% and new ink purchases by 35% while decreasing the time required to match colors during makeready.

Author: Edward Mijdam
Source: FLEXO, February, 1999, p. 28-31.