Industrial Printing Process Terms, ZTerms

Ink Transfer Curve

Ink-Transfer-Curve-terms

Ink Transfer Curve

General Definition

The Ink Transfer Curve is a vital tool in the printing industry that illustrates the precise relationship between the Dot Area defined on the printing plate (during the prepress stage) and the measured Dot Area on the final printed substrate (such as paper or film). The curve's primary purpose is to establish a measurement criterion for the accurate prediction and management of Dot Gain, ensuring uniformity and color stability throughout the printing process.

CMYK Ink Transfer Curves showing the relationship between ink applied to the plate and the resulting density on paper for press calibration.CMYK Ink Transfer Curves showing the relationship between ink applied to the plate and the resulting density on paper for press calibration.

CMYK Ink Transfer Curves: Ink on Plate vs. Ink on Paper.

CMYK Ink Transfer Curves showing the relationship between ink applied to the plate and the resulting density on paper for press calibration.

CMYK Ink Transfer Curves: Ink on Plate vs. Ink on Paper.

Real-World Usage

Press Supervisors monitor the Ink Transfer Curve primarily for tonality control, especially in sensitive areas. The curve ensures precision in Highlights (preventing detail loss in small dots, e.g., below 10%) and control in Shadows (avoiding excessive ink density or filling in 100% solids). In practice, devices such as Densitometers and Spectrophotometers measure raw print data (like Solid Ink Density and Dot Gain). This data is then analyzed by the RIP to model a Compensation Curve, correcting deviations. Utilizing this curve across different batches and presses is essential to guarantee color integrity and repeatability in consecutive print runs.

X-Rite eXact Spectrophotometer used to measure Solid Ink Density and Dot Gain (TVI) for precise color calibration in commercial printing.

Densitometer: Measures Solid Ink Density and Dot Gain for Curve Modeling.

X-Rite eXact Spectrophotometer used to measure Solid Ink Density and Dot Gain (TVI) for precise color calibration in commercial printing.

Densitometer: Measures Solid Ink Density and Dot Gain for Curve Modeling.

Consultant's Note

It's essential to remember that Dot Gain is an unavoidable physical phenomenon in printing, and the Ink Transfer Curve's goal is not its complete elimination. Rather, the curve aims to help the print shop identify the standard and predictable amount of dot gain for each machine and substrate.

Relying on this curve allows the lithography team to counteract the effect of dot gain by applying a Compensation Curve, also known as DGC (Dot Gain Compensation), during the prepress stage. Failure to utilize this data, relying instead on guesswork, leads to excessive color deviation between initial and subsequent prints, resulting in serious economic loss. Controlling the ink curve is considered part of the advanced frameworks for creating color profiles and Color Management.

Aligned with: ISO 12647 / G7 / Color Management Workflows