Why CMYK won't work in T-shirt Screen Printing

Why CMYK won't work in T-shirt Screen Printing

Getting high definition graphics with vibrant and accurate colours on T-shirts and Garments through Screen Printing process is simple, so simple that if one uses a right kind of dedicated colour separation software, along with high-quality inks and screens made from high tension low elongation yellow polyester mesh, coated with photopolymer emulsions and developed with high-resolution imagesetter positives or CTS (Computer to Screen), then the chances of colour matching errors reduces drastically. So with the correct software, procedures and systems, it becomes possible to get the desired print quality with consistency.

Photoshop or photoshop actions plugin are not dedicated software for high-end colour separations in t-shirts and garment screen printing.

Also, there is no way to cut down cost to get the right quality with consistency.

If screen printing is compared with digital print on one to one basis, then it's wrong. Every technology has some advantages and disadvantages. The advantage of digital technology is that one can print on a single t-shirt or print unique design on every single t-shirt or make each t-shirt personalized without incurring an expensive cost in make-ready and setup time. Digital printing machine also needs less space and workforce. However, there are few disadvantages of digital technology in a t-shirt, and garment printing, when compared to screen printing are listed below:

  1. It's challenging to match Pantone solid colours in digital printing because it uses only CMYK process colours. So without proper knowledge of file handling, workflow and colour management, its impossible to get accurate colour matching.
  2. Even if one gets nearby Pantone match, but still it's the combination of CMYK, and because of that reason CMYK dots are quite visible on solid colours when looked closely.
  3. Also, if the nozzles are choked up, then the lines within the solid colours are quite noticeable.
  4. Inks of many digital printing machines are not highly stretchable and crack easily if not treated well, particularly on dark garments when printing solid colours over the white under base.
  5. Hand feel is heavy on dark garments because of thick white under base ink because discharge printing is currently not possible in digital printing for dark garments so successfully.
  6. To operate a digital printing machine, one needs a highly expert and experienced person with sound technical knowledge on colour management.

I have not mentioned other crucial factors of digital printing such as capital cost, ROI, maintenance cost, ink cost and fabric treatment cost because in this article I am only focusing on CMYK v/s Spot Process Colour Separation Technique and its advantages over conventional CMYK process colour screen printing. Hence I don't want to confuse on digital printing v/s screen printing. No that's not my intention.

I intend to only focus on CMYK v/s Spot Process Colour Separation Technique concerning to screen printing.

Spot process colour separation is a unique technique to achieve high-quality graphics on t-shirts and garments, and this technique has been around in the industry over a decade. However, very few screen printers have understood and gained some knowledge of spot process colour separation but rarely use this method because of the unavailability of trained workforce to operate such software. Spot process colour separation not only minimizes downtime in colour matching on the press, but it also delivers bright and colourful prints.

Let me explain how a spot process colour separation wins over conventional CMYK process colour inks.

We all know Photoshop, and we use it day in and day out to convert RGB files in printable format, i.e. CMYK. Many experts also use Photoshop to manually separate spot colours from simple vector images, mainly which consists of solid colours. Complicated graphics becomes challenging to separate manually with consistency and accuracy in photoshop.

Secondly, why CMYK won't work?

Simply because in t-shirt screen printing, most of the time the inks do not deposit well with single stroke printing, especially on dark garments on white under base, for many reasons, e.g. due to poor edge sharpness of squeegee blade, improper setting of machine parameters, incorrect squeegee blade used, inconsistent ink viscosity and poor ink flow properties, screen choking too often, poor ink quality, high room temperature, and so on...

Here are five classic examples, why CMYK won't work?

  1. Why you need to print Cyan + Yellow to get Green when you can directly print exact Green
  2. If 60% Cyan and 30% yellow makes a particular Green considering single stroke, then what if Cyan or Yellow requires double stroke on a press due to improper ink deposition and various other factors. The colours will definitely change.
  3. Dyeing of the fabrics changes the appearance of colours after discharge or after a white under base.
  4. Tonal value changes as the ink viscosity changes on press
  5. Improper method of drying or inconsistency in dryer temperature can also change colours.

Remember, all ink manufacturers CYAN, MAGENTA, YELLOW is not made out of the same pigments and processes. Hence colour management becomes mandatory to grey balance CMY inks.

Screen printing with CMYK method is even more complicated and difficult because it requires skill and knowledge in colour Management with sound technical knowledge of RGB to CMYK file conversion, graphic file handling including workflow and information about RIP software (Raster Image Processor) plus imagesetters to output right positives.

Many screen printers still use old photoshop action plugins. These plugins have too many limitations.

  1. The method of separation remains similar for all images. However, every image needs a different approach in colour separation to get the desired colours.
  2. The base colours inside the plugins cannot be changed because those are photoshop action-based. However, independent separation software mainly developed for such applications always gives precise output and accuracy because there is much freedom to change the base colour in the software.
  3. Action-based plugins are easy to use as it's marketed worldwide using the simple term "single click." If this is that simple, then why screen printers are facing troubles to match colours close to the original. Because these action-based plugins don't have brains, they are blind, so they cannot see, read and check the graphic before separating colour. They separate colours with fixed profiles included with purchase and cannot be changed once installed. Later the graphic designers keep clicking after that "single click" to tweak the file, waste their time and finally fails to get proper results on press.
  4. License characters, brand colours, logo colours and Pantone colours become challenging to match with those simple photoshop plugins as it does not have options to separate special colours.

World over it's a known fact that screen printer who has struggled to produce good quality graphic t-shirts through screen printing process because of the limitations of the photoshop or photoshop action based plugins or through CMYK process colours have failed to take up such orders or either they landed up screen printing too many colours to get the complete tonal range by converting a graphic image into a vector art furthermore compromising on quality.

Apart from this crucial factor, even if one invests in a high end dedicated colour separation software, it's still challenging because of the limitation of qualified workforce with sound technical knowledge in spot process colour separation including colour science and theory for such applications. Along with the knowledge of colour separation, one also needs an in-depth understanding of the whole screen printing process, right from pre-press, screen making, inks, printing machines, fabric dyeing, ink drying and many other vital factors of the whole process.

Before investing in a high end dedicated colour separation software, it's essential to study and take some test prints and practice before achieving complete success from this new and advanced technique of spot process colour separation to screenprint graphic t-shirts comfortably with quality and consistency.

To educate our customers, friends and t-shirt screen printers, we at Grafica have heavily invested in many software in our in-house Screen Printing Institute, DMI (Dhirubhai Mistry Institute For Print Education Research) primarily for spot process colour separation, colour management systems to educate everyone to achieve their goals and success in graphic t-shirt screen printing business.

With our trained staff and workforce, we are giving away FREE Graphic Designs for T-shirts with spot process colour separations to every t-shirt and garment screen printers to practice and develop their screen printing skills with us.

Our independent screen printing institute DMI, an excellent initiative of our company Grafica Flextronica is aimed to teach screen printing technology, by sharing and providing FREE technical knowledge and training to every screen printers across the world since 2006.

Our mission is to provide FREE knowledge and education to every screen printers across the globe.

Our goal is to make every screen printer grow in the screen printing field comfortably with the support of our independent and dedicated screen printing institute DMI (Dhirubhai Mistry Institute For Print Education Research & Training).

Important Note:
Our designs should not be promoted or shared or sold or used for commercial purpose without our knowledge and information. It is strictly for education and training purpose only.

For more information about our designs, trainings and workshops. Call us on +91 250 66 96 250 (Extn. 216) or Whatsapp +91 91378 60311‬

Bhargav Mistry
Managing Director
Grafica Flextronica & DMI

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