Custom colors are achieved a number of different ways:
- With custom color inks, used most frequently on offset and flexo printing. This is the most direct process, and depends on accurate ink color matching and consistent density on press.
- Through icc profile color conversion from lab color to final output color. Most used for inkjet and digital output. With accurate icc profiling and well-maintained printers with sufficient color gamut, this can achieve good results.
- With recipe colors…CMYK simulations of spot colors. Used in all forms of printing where the use of actual spot colors is not possible. Using recipe colors is a very common approach, but it has serious limitations and without rigorous color management and process control in place from start to finish, it is doomed to failure.
The Problem with Recipe Colors
A recipe color is valid only for a very specific set of circumstances, and will totally fail if any of these conditions change. For example PMS 188 may be reproduced with 60C 90M 50Y with one printing process, but require 55C 100M 70 Y for another, and 50C , 88M, 58Y for a third.
And even with the same printing process, the CMYK combination that worked six months ago may fail today if press conditions have changed.
Making matters worse, many recipe color combinations have an uncertain origin, at best. They may have come from a years-old swatch book, from a “best guess”, from a Photoshop color library, or from a designer’s visual monitor match. In many cases, the color recipe will have been made with no reference at all to the actual press that will be printing the job. The result, in too many cases, is inconsistency, disappointing results, lengthy makeready runs, and inflated production costs as press operators struggle to modify color “on the fly”.
Bringing Order to the Process
The first steps towards establishing process control are well known: Establish a consistent process of measurement and monitoring of the basic elements of the print process, including ink color, density, overprint color, dot gain and gray balance, and implement consistent press practices that promote repeatability over time.
Shops new to printing to standards and process control may soon find that their old CMYK color recipes no longer seem to work, and the immediate reaction may be to abandon the concept altogether and revert to old seat-of-the pants methods, blocking progress before it as started.
In order for CMYK recipe colors to functions properly in a color-managed and process-controlled workflow, they must be matched to the actual printing standards that have been put into place. That means an end to color formulas based on guesswork, eyeball screen matches and blind faith.
With press standards established and firmly in place, accurate recipe libraries can be created from icc profile data derived from the actual press standard data. Alternatively, static CMYK recipies can be replaced by a true color managed workflow, where lab based spot colors are converted automatically within the rip.