Choosing The Right Ink For Your Printer

For many, getting into textile printing can seem a daunting prospect. As well as choosing the right printer, you also have to consider which ink chemistry is going to suit your application and fabric type best - which in turn, dictates the ancillary equipment required. Luckily, R A Smart have been involved in textile printing for almost 50 years and have a vast amount of experience with each ink type, putting us in unique position to advise and support you with the best solution to suit your business’ needs.

When it comes to textile printing there is no ‘one size fits all’ solution. The ink required will depend on a variety of factors. The first thing you have to ask yourself is – “What is my end application?”. For example, someone who is printing for fashion is likely going to require a different solution than someone who is printing flags. People printing fashion often require a solution that will offer good colour fastness, whereas flag printers are generally more concerned with light fastness.

Once you have that figured out, it’s time to decide “Do I want to print onto natural fabrics – i.e. Cotton, Silk, Linen etc.?” or “Do I want to print onto synthetic fabrics – i.e. Polyester?”. This can often be a difficult question for people, as many still consider polyester to be somewhat cheap and nasty which, nowadays, is simply not the case. There is a plethora of polyesters out there that successfully mimic natural fabrics such as silk & cotton, some of which even use 100% recycled materials.

Depending on your answers to those questions you will normally fall into one of four different chemistries:

Acid Dyes

These dyes were developed to work with protein fibres in fabrics – for example, those found in silk and wool. As such, they offer a limited range of fabrics for their user. However, if someone offers a very specialised service (for example, printing silk ties) then Acid Dyes can offer a very good solution. They are generally adopted by business who are printing for fashion.

The fabric used must first be pre-treated to allow proper absorption of the dye and also limit any lateral bleeding when it touches the fabric. The dye is printed directly onto the textile but often appears dull and subdued until the post treatment process is applied.

Acid dyes require a ‘wet’ finishing process which involves steaming and washing. During the steaming process the dye is ‘fixed’ onto the textile. It will change colour during this phase and colours are often much more vivid and bright once the fabric comes out of the steamer. Afterwards, the prints need to go through a washing process – this removes any excess dye that hasn’t been fixed and also the pre-treatment that was initially put onto the textile.

Reactive Dyes

These dyes were developed to work with cellulose fibres in fabrics – for example, those found in cotton and linen. Reactive dyes can print onto a much wider fabric range than acid dyes and can even be used to print protein-based textiles as well. They are often used by people printing for fashion or home furnishing.

Similar to Acid dyes, Reactive dyes require the textile to be pre-treated beforehand and they are printed directly onto it. The finishing process is also very similar and involves steaming and washing – however, the timings change as Reactive dyes cure quicker than Acid.

Pigment Inks

Pigment inks differ significantly from other solutions as they don’t fully impregnate themselves into the textile, rather they offer more of a surface print. In one way, this is a good thing as the composition of the fabric doesn’t necessarily dictate the successful use of Pigment inks – meaning they can print onto a large range of textiles. The compromise is their colour fastness may not be as good as one of the dyes.

Having said that, pigment inks have come a long way since they were first used in digital textile printing. Developments with the ink, along with pre and post treatment options mean that Pigments are now a viable option for many applications and one of the fastest growing segments of the market. They are particularly favoured by those in the home furnishing and household textile sectors as they offer good light fastness results.

Unlike with other direct to textile solutions, Pigments don’t require the textile to be pre- treated before printing. However, for the best colour fastness and most vibrant results, it is recommended.

They are also looked on favourably as they use a ‘dry’ finishing process, meaning they are ‘fixed’ using heat. This can be done in either a heat press or fixation unit. The colours generally won’t change much during this process and once it’s complete the fabrics are ready to be made into their end product (unless the fabric has been pre-treated, as some may wish to wash this off beforehand).

Disperse Dyes

Another massively growing sector for textile printing is the sublimation market. The inks used here are known as disperse dyes and can come in many different forms. Some are manufactured specifically to print directly onto the substrate (sometimes referred to as ‘true disperse dyes’), others are for paper transfer and some are a ‘hybrid’ of the two.

Your end application would determine which type of dye would best suit your needs. For example, direct disperse dyes can offer better light fastness and ink penetration, so are favoured by flag printers. Transfer dyes offer crisper prints and a larger colour gamut, so are favoured by sportswear printers. Regardless of the dye type, they are all manufactured to work predominantly with synthetic fibres, in particular polyester.

When the fabric or paper is printed with disperse dyes the colours initially look dull and subdued. It is only during the post processing that they will come alive. For sublimation this is normally a ‘dry’ process using heat, however direct disperse dyes can also be fixed using steam.

If conducting sublimation there are normally three key factors that come into play: time, pressure and heat. This usually takes place in either a flatbed heat press (good for rigid substrates or textile panels), a calendar heat press (good for lengths of textile) a fixation unit (for fabric printed directly with disperse dyes) or a high-pressure steamer (also for fabric printed directly). The term sublimation means when something transitions from being a solid, to a gas, then a solid again without entering the liquid phase.

Sublimation printing is one of the most diverse methods of printing on the market and people from all sectors utilise it creating everything from personalised products through to exhibition signage.

Hopefully that gives you a brief insight into some of the different ink types available for printing textiles. Here at R A Smart we have a friendly and experienced team of experts on hand to discuss your individual requirements and we are always happy to recommend the solution best suited to your needs. At our Cheshire based facility we have every type of ink chemistry in operation, along with all of the pre and post printing processes. To arrange a demonstration or discuss your requirement in further detail, please contact us on:

01625 576231 or [email protected]

www.rasmart.co.uk