Work Stuff
This is where I share stuff about my work, which involves color management, color sciences and best practices for digital printing systems.
You'll find project solution I've used over the years, maybe a spreadsheet or PDF guide or two, as well.
SCTV Linearization prior to CMYK-OGV Characterization
Catchy Title, don't you think?
The IDEAlliance PPC has been working on a kit and the procedures to characterize 7 Color printing presses with the goal of creating a set of Commercial Reference Print Conditions for the extended CMYK-OGV color space. These CRPCs would be an extension of the current set in ISO 15339 (CRPC1-7 aka GRACoL 2013) and would serve the same purpose. As standardized color spaces for system certifications and a goal for companies interested in consistent color output.
To that end, the very first steps in the process are to create G7 and SCTV curves for the primary ink set. This is to ensure that the printing machine is in grey balance and that the additional colorants are printed with linear tone values.
Getting the G7 curves is the easy part. Lots of software out there does this now, but few also provide correction curves for SCTV. So, I made a handy little spreadsheet which calculates them based on the SCTVi6 print target distributed with the IDEAlliance ECG Project test kit. If you have ORIS software, you can use the Reference file in the kit and measure with a IO table. If not, there is a "Cut and Paste" version to copy Lab values from a text file.
Credits to Mike Rodriquez via Hutchcolor.com for the Lab-XYZ formulas and to cielab.xyz for the D50 and U-functions.
Click the image above to download the spreadsheet and sample data from my secure Dropbox link.