Wide Format Week
The power of colour profiles
A single RIP software platform for all devices improves accuracy
September 24, 2023 By Angus Pady
I want to share a case study about the benefits of colour management in daily production. I had the opportunity to collaborate with a fully digital reproduction company that operates two flatbed printers and two roll printers. Their goal was to maintain colour consistency across all devices and reduce the time and effort spent on adjusting colours to match Pantone colours. Additionally, they had specific brand colours that needed to be accurately reproduced.
Previously, they utilized profiles downloaded from the RIP vendor on one machine, while on the other flatbed, they relied on custom profiles created years ago for a specific media. For roll devices, they utilized profiles included from a different RIP.
During our discussion, I suggested utilizing a single RIP software platform across all devices to maintain consistent colour output. This approach ensures the same underlying colour management process is applied to all printers, resulting in improved colour accuracy. Additionally, using a single RIP software can simplify spot colour reproduction.
Initially, I worked with flatbed printers that utilize UV-cured ink. Through my experience with UV and LED curing systems, I have come to realize that it is unnecessary to develop a profile for each individual type of media. Instead, I opt for a media with a neutral white point, which serves as my profile for all media. This is because on UV and LED curing printers, the ink adheres to the surface of the media and is bonded with the LED/UV lights. The sole difference in colour lies in the media’s white point.
I have measured various batches of styrene and coroplast and the white point varies from batch to batch. One can be blue while another can be neutral. The same is true for coroplast and other media.
A master profile
Printing and colour management become easier with a single master profile. There is no need to guess which profile to use, and managing your spot colour library becomes simpler. Most importantly, if you need to re-profile due to a change in colour, you can do so within an hour to bring the machine back to its baseline. I have come across systems with six to eight profiles created at different times, and redoing all those profiles in case of colour drifts can be a daunting task.
Some have argued against my theory, claiming that I am not taking into account the media’s white point. While this may be true, it’s important to note the white point is constantly shifting. Although profiling the bluer styrene may provide a slight advantage, there’s no guarantee the next batch will be the same colour. Additionally, some argue different media types require separate profiles due to their unique characteristics. However, this is not the case with UV and LED-cured inks, as they do not behave like aqueous or solvent inks.
Getting back to my customer. I created one master profile for each machine. I then tested the colour on three different media. I measured the colour between the two flatbeds. The primary and secondary colours (CMYKRGB) were within 1.1 DE00 average to each other. Visually you could not see a difference between them. They did share the same ink set. I then compared the roll printers to the flatbed and the variation in the same colours was an average of 2.3 DE00. Still a very close match but there was a slight saturation difference. However, the colour was really close.
Lastly, I measured the Lab values for the custom brand colours and created new spot colours in the RIP. We printed and optimized the brand colours for each printer. The brand colours now matched so that if they colour print a job on any of the four printers, they would be visually very similar.
I wanted to share this experience because this customer had been doing a great job with printing but spent too much time every day making colour adjustments. I revisited the customer after a few months, and they said that now they are able to print, and they don’t have to think about colour. If they get a new custom brand colour they know how to measure it and load that colour into the RIP, print the swatches and choose the best version. This becomes the brand colour for that printer. That process takes 30 minutes. The operator said, “Now the greys are grey.” Yes, the foundation of colour that you may recall from my last article.
Angus Pady is a G7-certified expert that has helped customers resolve colour management challenges for over 30 years. He can be reached at firstname.lastname@example.org.
This article originally appeared in the July/August 2023 issue of PrintAction.
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