Process Control Is Key to Effective Ink Optimization

One of the keys to efficient package printing is understanding the source of unwanted color variation and implementing measures to drive those deviations out of the process.

Whether it occurs on a particular press during a single run or among different presses, color variation is a natural part of the print reproduction process. It is also anathema to packaging end-users, for whom color consistency on the shelf is a critical element of a product's appeal to the customer. At the same time, increasing cost and deadline pressures have raised the stakes for converters to print jobs quickly and efficiently, match the proof, use as little ink as possible, and generate minimal waste. One of the keys to efficient package printing, therefore, is understanding the source of unwanted color variation and implementing measures to drive those deviations out of the process, eliminating the need to take costly corrective action at the press.

While ink usage represents only a small fraction of the overall cost of a print job, it can have a significant impact on pressroom efficiency and the quality of the finished product. As a result, effective ink management techniques—specifically, ink optimization solutions—have assumed competitive importance as a means of stabilizing the printing process and achieving cost savings.

Various ink optimization solutions on the market aim to ameliorate color variation, reduce ink usage, cut costs, and boost productivity by:

• Improving printing conditions;

• Promoting faster makereadies, shorter drying times, and faster finishing;

• Reducing waste; and

• Producing from 15-25 percent savings on ink, depending on the process and substrate involved.

Benefits are also said to include improved reproduction quality; better neutrals; more consistent total ink coverage; and easier color space transformations, as well as cleaner (greener) runs, faster absorption, reduction in rub-off, and potentially higher printing speeds.

Shades of gray

In all cases, the mechanism for achieving ink optimization is known as GCR or Gray Component Replacement, which changes the separation of an image by taking color from the file and increasing the black channel, resulting in a visually and spectrophotometrically nearly identical separation that uses less ink. This, in turn, improves the quality and consistency of the printed result in cases where unwanted tinting of the plate occurs. This is especially useful for high-speed web presses, where a color shift on press could affect many sheets in a short period of time. Long-run sheetfed work also will benefit, yielding consistent, repeatable color during the entire press run. Cost savings result, in part, because cheaper black ink is used replace the more expensive CMY variety.

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