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Smart Inking: reducing ink costs with effective colour management

In what remain tough trading conditions, Dean Derhak, Product Director at SAi, explains how both effective colour management and media profiling can help sign shops and large format print providers slash ink costs and still keep customers coming back.

As part of my job, I visit sign shops and large format print businesses to see what processes they’ve implemented in the quest to increase their profits.

Dean Derhak SAi
Dean Derhak, Product Director at SAi

One of the questions I ask is how much their ink costs are per square foot on their printers. Two out of three shops say they don’t know. I also ask how much ink they waste and again, few actually know, with some admitting that they would rather not know lest they discover the inconvenient truth.
Knowing your ink costs is basic good business practice – it can help you better quote your jobs and reduce ink usage. For example, a print shop spending US$ 35k a year on ink that learns to save 15% on ink would make over US$ 5k in additional profit per year. Better yet, smart colour management can save you even more.
Calculating the average ink cost per square foot over a given period is easy; you simply take the total area each month you’ve printed and divide it by your ink costs – the print area being your actual print area.
Most RIP software packages have a job log within them, which you can use to get your total substrate used. Some RIP products show total print area per job, while others give the width and height for jobs, thereby requiring a manual calculation. Tally that up for the month, and you have the overall area printed.
Other ways to determine this figure exist: on devices like the HP Latex Printers and HP Designjet Z6200 Printer, a built-in web server tells you how much print area each job used. SAi is also developing a mobile application that gives the total print area per job on your iPhone or Android device.
As for calculating ink costs, this merely requires adding up the amount of cartridges you’ve gone through over the same month and their cost. As an example, if a sign shop produces 480 square feet of output in one month and its ink costs are US$ 390, its average cost per square feet over that month is US$ 1.23.
Importantly, this formula factors in unused or wasted prints and takes into account ink head cleaning and purging. This enables you to work out your true total ink costs per square foot – not ink usage. What matters is how much you spent on ink and how much you printed.
Some shops only quote jobs using a single per-square-foot cost. However, not all print jobs use the same ink, so quotes can be costing you profits. When you truly know your ink costs per square foot, you can quote jobs on low, medium and high ink usage and maximise your profits on each job.
If you’re just starting out, obtaining the right media ICC profiles is essential. A surprising number of print shops mistakenly use one generic media profile on all media, and in the event of an ink problem, they will simply use colour correction to adjust the inks. Not only does this waste a tremendous amount of ink, but makes spot colour matching much harder.
Color Management feature Shot2So the first step is to get ICC profiles for each printer and media, and select the matching profile each time the printer operator changes media. Otherwise, you’re wasting a lot of ink without realising it, which will escalate your ink costs unnecessarily. Getting ICC profiles is very easy; they are typically obtainable from your RIP manufacturer’s website, as well as from printer manufacturers and media suppliers.
For complete control, I recommend building your own ICC profiles, because despite the cost and training required, the investment will pay off over time. Most print shops would acknowledge that the ability to reduce ink costs, while maintaining customer satisfaction is a highly desirable goal. What constitutes high colour quality is essentially whatever customers’ say is high colour quality. Taking control of your colour management makes this possible.
If the objective is to meet or exceed customer satisfaction, while dramatically reducing ink costs, then a good way to start is to look at light ink usage. This is basically the light cyan and magenta inks which have more clear liquid and less pigment. Printers use a lot of these inks even when they aren’t needed. The sole purpose of light inks is to improve image smoothness for close-up viewing.
Reducing light ink usage can save up to 25% on annual ink costs. The caveat is that, while there is a cost saving and the gamut won’t be hugely affected (darks are still dark, grey balance is still present), it will look less smooth close up. As a result, effective use of this technique depends upon the application and the viewing distance required.
Exploring different ways to produce grey or black is another way of reducing ink costs. Most default ICC profiles use a lot of CMY ink to print grey, black and shadows, but this actually uses up to two-thirds more ink. Although it often depends on the media – backlits, for example require a lot of ink – selecting a GCR curve that replaces CMY ink with black ink can radically reduce your ink costs with little impact to quality. Indeed, this is especially so in dark areas. You can find the GCR curve control in your ICC profile making software.
The option to replace CMY ink with black ink is really worth investigating as it still allows you to achieve good colours with less ink, and even with some loss in detail, it will deliver richer blacks. Some ICC profile engines even have settings called ‘Max K’ which replaces CMY with black. This technique alone can potentially save another 20% of your ink usage per job.
The only real disadvantage with this is that on close-up viewing, small black ink dots known as ‘peppering’ may be visible in highlight and mid-tone areas. Also, if over-used, colours could be blown out, reducing some detail in shadows. Where these levels are set depends on the media, so you need to experiment a little. Either way, replacement of CMY with K is definitely worth considering as it can dramatically reduce ink costs.
As you can see, it is also essential to know the intended viewing distance when you’re quoting a job. This has a lot to do with what you can get away with, while still keeping the customer happy.
Ensuring customer satisfaction and reducing ink usage can also be helped by going beyond default profiles and profiling media for purpose. A lot of print businesses use just one profile for a print mode; regardless of the viewing distance required. Operating in such a way wastes a tremendous amount of ink and in some cases, print time.
The cost-effective approach is to profile the same print mode in different ways for different purposes. If you’re profiling for different modes, for example high quality (typically slower speed and lots of ink) it’s easy to ‘over-ink’. Although the output looks fantastic, the same result could have been achieved with 20% less ink. This is especially so with coated media, which soaks up ink – and invariably your profits - so well.
Most inkjet printers have a ‘quality’ print mode as the default ICC profile, but you can make your own profiles for ‘speed’ and ‘economy’ modes to save ink and time costs. In ‘speed’ mode, you want to reduce light inks and set GCR to ‘Max K’, go to unidirectional printing, reduce the dpi and lower the passes. This is the mode to select for time-critical jobs where viewing distance is long.
Regardless of how much ink the media can actually take, ‘economy’ mode arbitrarily reduces ink by 20%. It reduces the light and dark inks and by following the settings for ‘speed’ mode, often the results will be indistinguishable.
Of course, some of the techniques I’ve discussed take a bit of practice, and factors like different media characteristics and printer temperature settings need to be considered. However, these are all colour management variables that you can control to your profit advantage with smart colour management. You’re not obliged to pass on the savings achieved form these techniques to customers, and that, as they say, is the bottom line.

Dean Derhak

Printed with thanks and acknowledgements to Graphic Display World (UK)