Modern methods of design development and screen making in textile printing have revolutionized the industry by integrating technology and precision. Design development often begins with Computer Aided Design (CAD) software such as Adobe Photoshop, Illustrator, or specialized textile design tools. These tools enable designers to create intricate patterns, perform color separations, and visualize repeat designs with high accuracy.

In screen making in printing, traditional methods involving manual preparation of silk screens are increasingly replaced by advanced techniques. Laser engraving directly etches designs onto screens, offering unmatched precision and speed. In this article I will discuss various modern methods of design development and screen making in textile printing.

Modern Methods of Design Development and Screen Making in Printing

Traditionally, separation positive films would have either been hand-made or produced photographically in order to make each screen. In a later development the hot wax print system was also used to mask pre-coated screens directly, followed by UV light exposure.

The making of a printing screen is a delicate and lengthy multi step process. The steps are as follows:

1. Design drawing
2. Cover the frame with gauze
3. Fasten and stretch the gauze
4. Photo-chemical method of design transfer
5. Light-sensitive coating: (a) chrome-gelatin or (b) chrome-PVA
6. Application of the light-sensitive coatings on screen
7. Print the color separation diapositive on the light-sensitive coating
   1. Method of printing using large-size diapositives
   2. Step-up method
8. Wash the exposed screen to remove non-hardened solution/emulsion from unexposed area from the screen; and finally, paint for improved durability of the screen

Here are given some modern methods of design development and screen making in printing.

A. Computer aided design (CAD):

By far the most important developments in textile printing of recent years have been in the field of “computer –aided design” (CAD). Associated with these advances has come laser engraving, and INK-JET printing. All these depend upon the successful digitization of the design that means the conversion of design information into binary code in a form that can be stored in a memory of a computer.

Customers generally placing orders after strike-offs have been submitted. A strike-off consists of a few meters of the correct fabric printed with each color way of the design. These are normally produced on a sample table or even on the production machine. Unfortunately, many of the designs that are engraved, and strike-offs are made are never printed in bulk, and so the expense of screen engraving has been wasted.

The use of a CAD substantially reduces the time taken to produce repeat sketches, color separations and color ways. When the design system is linked to an Ink-Jet printer for proofing, this may allow the decision to engrave screens to be delayed until orders are forthcoming.

Although it is now possible to create a design on the color graphics monitor of a CAD system using a “Paintbox” or “Photoshop” or similar software package with a pressure-sensitive stylus or a mouse.

Typical CAD software:

A typical CAD design for textile printing purpose should have following Facilities

• Color reduction
• Putting the design into repeat
• Scaling the design to fit screen
• Drawing and brushing
• Mirror, inverse and replicate functions
• Overlap
• Fall-ons
• Capturing, copying, moving and scaling motifs
• Zooming in on small areas in order to edit them
• Changing colors
• Shading and stippling
• Color separation
• Dot removal (deleting stray dots in a color separation)

When the design is satisfied, design information can be downloaded to a disc, to a film plotter, laser engraver, etc.

B. Scanning

The original artwork is then digitized by a scanner. The design information is stored in the computer memory, one pixel (picture element) at a time. Most design-creations are still produced in the traditional manner, with paint brushes or airbrushes on to paper or card.

Drum scanner:

A scanner analyses the design one line (that is, one row of pixels) at a time, converting analogue color information into digital form.

Film plotter (the digital manufacture of films):

A scanner scans the design and stores this digital information. For further processing of the design the data are transferred to the design manipulating station. This process may include (see before) the data resulting from this processing stage which are stored on the optical disk and are fed to the film plotter. Thanks to modern electronics the required films are exposed at high speed by a laser diode at extreme accuracy. The plotting resolution is 3-80 points/mm, at a speed of 900 revolution / minute. Films up to 2m² can be processed. With this system a “long” film can be produced, so a step-and-repeat machine to copy the design to the screen is not needed.

E. Color reduction

The normal procedure is to scan a design at low resolution, and then display it on a color monitor. At this stage large numbers of color will show. The next step is color reduction, whereby the design is simplified into a manageable number of colors.

F. Color manipulation system

The color manipulation system can be used to color designs by combining color separations for those designs. One can select the colors from color catalogues, like Pantone or via color measurement with the aid of a spectrophotometer. The coloring system is used to color designs in a number of color ways and to make a prediction on the appearance of the print result. This prediction is made on the basis of the dyestuff that are available in the color kitchen or by the dyes which can be used based on the Color Matching Software On the basis of the approved color recipes, one will know beforehand that the selected colors can actually be produced. The color ways could then be printed on a Ink-Jet printer to get the “go ahead “from the customer.

G. Laser engraving

The use of high-powered laser for engraving screens is a development from their use for engraving rubber-covered flexographic printing rollers. A British company ZED and the Austrian company STK (Stork STK) came up in the mid-eighties with the first screen laser engraving machines which revolutionized the rotary screen making process. With laser engraving, the digital information that contains the design for a specific screen is directly transmitted from the CAD system to the engraving machine. The pattern is then applied to pre-lacquered screen, i.e., the lacquer is removed with the aid of a high-energy laser beam and clears the perforations as per the design. Direct conversation of digital design data into an engraved without the intermediate stage of films offers a number of important advantages:

1. Speed: A screen produced on the laser can be ready for use within 30 min. A screen produced by the standard method could take up to 2 hours minimum.
2. Accuracy and reproducibility: Digital info is direct converted into a design. Consequently, joining problems as they could occur with film are excluded. The laser engraving process is reproducible even after years and the information are stored in digital form.
3. Environment-friendliness: The laser engraving process neither involves development nor does it produce wastewater. The lacquer particles that are removed are sucked away and collected in filters, so no pollution.
4. Efficiency: Thanks to the high speed and high production capacity, this process saves cost in comparison with conventional engraving.
5. Not depending on skill: As the whole process is computer controlled, it does not need human skill.
6. No need for huge screen storage for repeat orders.
7. A damaged screen can be replaced in a short time to continue production a printing order, which otherwise has to wait for a day or so to replace the screen in the conventional method.

Laser exposure machine:

A laser exposure machine is a device used in various industries, such as electronics, printing, and manufacturing, for high-precision processes. It utilizes laser technology to expose materials or create patterns on surfaces. In textile printing, laser exposure machines are used for creating high-quality, detailed patterns on fabric or screens used in screen printing. This technology plays a crucial role in the preparation of screens for rotary or flatbed printing, as well as direct laser engraving on textiles.

Stork introduces a completely new technique, suitable for both the engraving of screens and for applying designs to galvano mandrels.

Mask exposure machine:

The Maxis an engraving system where a wax mask is applied to the light-sensitive lacquer on a screen with the aid of a jet print system. The jet print system is directly actuated by digital design information. Once the negative part of the design has been coated with this mask, the screen is exposed to light in this machine. After exposure, the lacquer on the screen must be developed and then polymerized, in precisely the same way as it would happen with the conventional engraving method. Advantages of the MAX are the speed with which a screen can be engraved, the high quality that is achieved and the fact that much time is saved by the direct digital processing of the digitized design, without the use of films. Joining problems are thus a thing of the past.

H. Ink-jet engraving

Ink-jet engraving or Wax – jet engraving technique is a method of producing economic and environmentally conscious, high quality rotary and flat screens. With this method, rotary screens or flat screens are engraved without the transparencies and hence CAD system is directly used for producing the exposed screen. The screen to be engraved is coated with the photosensitive lacquer as in the traditional method.

The coated screen is printed or coated with finest wax droplets with the aid of the ink-jet technique. In the case of the rotary screen, this is done with a cylinder rotating about its longitudinal axis, along which the ink-jet head is guided. Flat screens on the other hand are inserted in a vertical machine frame, and the ink-jet head “removes” the screen areas to be engraved line by line. The graphics file, which is retrieved directly from the CAD machine via a LAN or by an integral computer, serves as the control data file. The spray technique used is the so-called “Drop-On-Demand” process (as explained in the inkjet printer section.) the negative print which adhere to the screen is impervious to light. The printing head does not spray aqueous dyestuff, for example, but wax. This material is thermoplastic. To prepare it for spraying, it is heated in the printing head. Even though the viscosity of the drop is less and it may flow in undefined form over the screen surface on impact it is avoided since the wax droplet changes its viscosity in the flight stage as it begins to cool, finally hardening in contact with the screen surface. Actinic light absorbent additives, which reliably prevent irradiation of the wax particle, can be introduced into wax. The wax develops natural adhesion to all known photoelectric layers, without “sticking” too hard. In this way, it adheres securely to the screen photoelectric layer on the one hand, and on the other can be washed off easily enough in the developing process. Further development of the screen is done in the traditional way except for the removal of wax which is very easy. This new technology has many advantages.

Advantages of Ink-jet engraving

1. The technology is very simple and except transferring the engraving transparency, though by a new method. All other processing stages, i.e., coating, exposure, development, thermal or chemical hardening if necessary, through to retouching, remain unchanged.
2. The ink-jet technique imposes minimal requirements on screen positional accuracy, because, in contrast to the laser technique, no focal range has to be adhered to. The screen is very simply pneumatically stabilized with a minimum over pressure of 0.02 bar. In contrast, the flat screen is brought into the plane position by means of a partial vacuum. Screen positional tolerance has very little effect on picture detail representation.
3. The inkjet technique speed can be increased by increasing the number of jets, whereas in case of laser increasing heads is restricted due to cost.
4. The ink-jet technique produces no seam, as is familiar from conventional film engraving, and is dreaded with certain patterns.
5. The ink-jet has a special advantage of checking the print on a paper before actually engraving. For example, suppose the printer has a doubt about the resultant print of a critical half-tone, it can be printed out on paper which has been laid on the screen by way of a proof. (It has been found that an inkjet engraving can produce on the screen an image (graphic) almost identical with the subsequent print with this screen. Therefore, when in doubt about the resultant).
6. In inkjet method the thickness of the coating does not pose a problem, whereas in case of laser engravers it may be a problem in some cases.

Inkjet exposing machine:

An inkjet exposing machine is a modern alternative to traditional screen exposure methods, primarily used in screen printing. Instead of using light-sensitive emulsions and films, these machines use inkjet technology to apply designs directly onto screens or substrates, simplifying the exposure process.

Conclusion
Modern methods of design development and screen making have significantly advanced the textile printing industry by integrating cutting-edge technology and innovative practices. These techniques have streamlined the creative process, enhanced precision, and reduced production time while promoting sustainability. From CAD software and AI-driven design tools help to designers and manufacturers to achieve intricate designs with efficiency and eco-friendliness.

References:

1. Kolanjikombil, M. (2024b). Printing of textile substrates: Machineries and Methods. CRC Press.
2. Choudhury, A. K. R. (2022). Principles of Textile Printing. CRC Press.
3. Miles, L. W. C. (2003b). Textile printing. Amer Assn of Textile.
4. Cie, C. (2015). Ink jet textile printing. Elsevier.

Author of This Article:
Jahanara Akter
Fashion Designer & Ex-Lecturer,
Dept. of Fashion Design
KCC Women’s College (Affiliated by Khulna University)
Khulna, Bangladesh

Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.

Share this Article!