CORRECTION OF MEASUREMENT CONDITIONS IN DIGITAL PRINTING MACHINES

• US 20200137264A1
• Filed: 10/17/2019
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Heidelberger Druckmaschinen Ag
• Original Assignee: Heidelberger Druckmaschinen Ag
• Inventors: PFEIFFER, NIKOLAUS, BOLLMANN, STEFAN, THOMSEN, HAUKE
• Granted Patent: US 11,272,077 B2
• Time in Patent Office: Days
• CPC Class Codes: H04N 1/00323 with a measuring, monitoring or signaling apparatus, e.g. for transmitting measured information to a central location
• CPC Class Codes: H04N 1/603 controlled by characteristics of the picture signal generator or the picture reproducer
• CPC Class Codes: H04N 1/6086 by scene illuminant, i.e. conditions at the time of picture capture, e.g. flash, optical filter used, evening, cloud, daylight, artificial lighting, white point measurement, colour temperature
• CPC Class Codes: H04N 1/6088 by viewing conditions, i.e. conditions at picture output

Abstract

A method performs color control in a printing operation on a printing machine by use of a computer. The computer uses an input profile to transform print image data from a first color space to a device-independent color space, subsequently uses an output profile to transform the print image data into a second color space dependent on the printing machine. The computer compares measurement conditions of the used input profile and of the output profile to be generated, and, if there are differences between the respective measurement conditions, adapts the print image data in the device-independent color space to deviating measurement conditions of the output profile. The printing machine subsequently executes the printing operation using the print image data, and wherein UV light excitation is used for the measurement conditions of the output profile.

Claims

1. A method for performing color control in a printing operation on a printing machine by means of a computer, which further comprises:

providing the computer an input profile and the computer uses the input profile to transform print image data from a first color space to a device-independent color space, subsequently the computer uses an output profile to transform the print image data into a second color space dependent on the printing machine;

comparing measurement conditions of the input profile used and of the output profile to be generated, and, if there are differences between the measurement conditions, adapting the print image data in the device-independent color space to deviating measurement conditions of the output profile;

subsequently executing, via the printing machine, the printing operation using the print image data; and

using UV light excitation for the measurement conditions of the output profile.

2. The method according to claim 1, which further comprises using International Color Consortium profiles for the input profile and the output profile.

3. The method according to claim 1, wherein if the measurement conditions differ, to adapt the print image data, the computer performs a conversion where the computer converts the input profile to match the measurement conditions of the output profile when the output profile is created.

4. The method according to claim 3, which further comprises creating, via the computer, a respective output profile for every different measurement condition on a basis of a converted input profile.

5. The method according to claim 3, wherein if the input profile is known, the computer looks up the measurement conditions that were used to create the input profile in a table and uses known measurement conditions to make the conversion if the measurement conditions differ.

6. The method according to claim 5, which further comprises saving the table in a database to which the computer has access.

7. The method according to claim 5, wherein the computer makes the conversion by means of a device link profile between the input profile and the output profile, and adapting the device link profile to deviating measurement conditions in the method.

8. The method according to claim 3, wherein if the input profile is unknown, the computer makes an estimate of the measurement conditions of the input profile on a basis of a paper class and lab value of a paper white that have been used and uses the measurement conditions estimate to make the conversion if the measurement conditions differ.

9. The method according to claim 8, wherein the computer makes the conversion by means of an estimate of a white dot shift caused by different measurement conditions and an inverse white dot correction of the input profile.