Clearing up colours in print once and for all, we hear from Paul Hesketh, Print Development Manager, FFP Packaging Solutions Ltd…
As everyone knows, you can make any colour you like on a screen with the three ‘additive’ primary colours Red, Green and Blue (RGB) and
any colour you like, within reason, in print with the ‘process set’ of three subtractive primary colours Cyan, Magenta and Yellow, with the help of Black (CMYK – the K doesn’t refer to ‘blacK’, incidentally, it is the ‘Key’ ink that adds contrast and definition). In brochure printing, or carton production, it would be unusual to add more colours than these four unless a special effect is required, but in flexible packaging printing onto plastic films using flexo or gravure, eight, ten or even more colours are regularly used.
Now, given new approaches, and new investments in colour management and new advances in plate and press technology, it is becoming more and more common for flexible packaging printers like FFP to print using Fixed Colour Palette (FCP), in a standard CMYK process set, usually with white. Brand owners can save money in set up costs, cost of inks, design and repro, increasing flexibility in print and reducing time to market. It isn’t the right approach for all designs but it can offer significant savings in some circumstances, particularly across a range of similar products, for example where the material used and the pack size remains the same, with changes to the design that include a variation in a main, strong colour.
A typical design for flexible packaging would be ‘separated’ using the process set CMYK, plus a number of ‘solid’ colours. The process set is
used to create the photographic elements of the design while the solid colours are used for the rest of the design. Typically defined by
Pantone® colours or by matching swatches of special colours, these are set-up in the printing press as separate ink stations, with their own wash-downs, plates and rollers, and the ink is mixed specifically for the job, which means that any leftover ink can be wasted. Until recently, this was the only viable approach, because trying to print both photographic detail and solid colour using the process set was impractical, the requirement for high ink density in solid areas making it impossible to get the detail and accuracy in the photographic elements of the design.
So, what has changed? Key to the development has been a new approach to colour management. Throughout the industry, the leading printers have introduced new equipment to manage colour through the workflow with the objective of bringing measurable consistency to the printed design. Colour can and should be measured. Spectrophotometers both on line and in the colour lab give us clear data. Colour management in flexible packaging is complicated by the variety of materials in use and whether those are surface or reverse printed, each combination of which may demand a different ink system.
At FFP, we have approached the issue by creating a complete set of colour profiles, each predicting the interaction of colours on press for specific ink/film/substrate combinations. Colour profiles are created for each individual film or substrate with each ink system. This is
achieved by printing various tint combinations of CMYK process inks in the form of a test chart. The resulting standard is scanned patch by patch using spectrophotometry to create an ‘ICC’ profile and a complete printer’s colour specification. This is time consuming but vitally necessary. Every new design coming into the business is assigned the relevant ICC profile determined by the job specifications. This then allows us to accurately predict the colour via a calibrated proof that is supplied to our customer.
We now have the tools to predict measure and control colour on press. This technology has been key to enabling Fixed Colour Palette printing to be brought into the mix. We have created a set of ‘solid’ colours using CMYK inks that broadly follow the Pantone® book. In addition, developments in plate and printing press technology has meant that things like print impression and ink weight have become more controllable, with very low pressure on the press resulting in a complete ink transfer to the film using the latest digitally imaged printing plates.
About two thirds of the standard set of Pantone colours are achievable using the FCP approach, and FFP are helping designers by producing a reference tool, a colour book with reverse printed laminated ‘pages’ featuring swatches of more than a thousand available colours with ‘numbers’ that designers can choose from, confident in the knowledge that the colour they choose from the guide will match the result on press.