Ink and colour

For those of you who did not attend Asia CanTech In Bangkok I wanted to give you a snapshot of my presentation at this event. With the colours of fall starting to take over the landscape in the US I decided to talk about colour.
Cost control is the hot topic for any manager. How we as ink suppliers help you control these costs is the basis for the following looking at colour and ink and how to reduce the costs associated with them.
First of all we must ask, ‘What is colour?’ As shown below, colour is measured in nanometers from the visible spectrum. In other words colour is light. What we see are the light waves that are reflected off the surface of an object. The other light waves are absorbed. So all objects are reflectors. This is the basis for all colour theory measurements.
Without getting too technical, this light we see reflected determines what colour we see. Or what colour ink you want to print on a design. But we do not talk in nanometers or lab readings when discussing colours. We use the Pantone guide in most cases to communicate with each other when discussing colour.
Yes, the Pantone guide – one of the most quoted guides in our industry, but also the most misunderstood. More and more customers are using this guide to communicate their colour needs.
So what is Pantone?
The Pantone Matching System, or PMS, is the internationally recognised standardised colour-matching system that is owned by the Xrite Corporation. Because individual perceptions of the colour spectrum vary widely, the Pantone system is used throughout colour-critical industries as the definitive source for accurate colour
communication, ensuring that colours are consistent across projects, designers, printers and companies. The concept of the first Pantone formula guide was relatively straightforward. If you print a guide of ink swatches under very close tolerances, and you assign a number to each colour in the guide, you have provided a way for printers, designers and ink manufacturers to communicate colour.
The Pantone System for colour adds a suffix to the Pantone colour to indicate what might be called the “output intent” of the colour. Over the years, the following suffixes have been used:
U     =     uncoated paper
C     =     coated paper
M     =    matte paper
The output intent for 185C is that this red is to be matched on white Coated paper. In our industry too many people expect that when printing on metal they will get the same output as they see on coated paper. The truth is we print on white coatings and white prints of ink as well as size coated bright metal. These are in no way as white as the paper they show these colours on. That is the reason why it is called a guide. It is the only guide we have for our industry. Remember all industries use this guide for their process too, from medicines to textiles. When trying to match tinted colours from the guide, this becomes even more challenging to get close to some PMS colours.
Remember the way a Pantone guide works. The centre colour on the page is the true colour. As you move up the page tint base is added to make the colour weaker. As you move down the page black is added to make the colour dirtier. The intent of this guide is to give economic starting combinations for the most commonly used colours. It is not intended to replace proper training and experience in colour matching.
Please keep in mind problems that can be caused by using the wrong pigments. Refer to the list of bases and see if a particular base is appropriate, at the amount you want to include in the formula, or in combination with the other bases you want to use and for the intended application.
How to translate Pantone shades to metal
When printed on metal, colours are always dirty compared to the Pantone guide because metal deco prints on WBC, white ink and size-coated stocks and the Pantone guide is printed on bright, white paper stock. Another problem is that Pantone uses pigments that the three-piece industry cannot use (fugitive pigments). Our pigments must be heat stable and in some processes permanent pigments must be used.
We can get closer to the stronger Pantone colours but the weaker cleaner colours are more difficult due to the substrates we use. We get the colours as close as we can, and send the prints to the customer for approval. Our customer’s customer will need to decide if we have matched the Pantone colour close enough to satisfy the label requirements.
So how does this information help you control costs in your workplace? Knowing the colour and what the process requirements are will allow you to correctly chose the pigments needed for the colour you need to match. Take for example yellow. Most yellows on size coat will be opaque. Transparent yellows tend to have a metallic gold appearance when printed over a size coated substrate. The best strength can be achieved by using red shade, transparent yellow. The best opacity can be achieved by using opaque, green shade yellow.
While RS is considered permanent, and can be used in any amount, Opaque GS is not permanent and should not be used below 10 per cent. Green shade yellow is very clean and transparent but is also weak. GS Yellow is typically used only in very clean greens and should also not be used below 10 per cent in a formula. If it is necessary to make the shade redder than straight RS yellow, use permanent orange or YS red. Permanent orange is more expensive, but cleaner and more permanent than YS red.

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