Chapter 3
Creating Artwork For Screen Printing Textiles
This is the first and foremost task to accomplish on the agenda. Without art, you have nothing. It is also important to note that setting up art for screen printing is different than that of other types of printing. Your art is critical. It needs to be set up properly for screen printing so that it may print easily and look great. Make sure your artwork is right before you go to screen. It is wise to spend as much time as is needed to get it done correctly. This tutorial course is focused on the actual process of screen printing. But here is some information about creating artwork that will be helpful starting out.
There are many ways of generating artwork from simply hand drawing to using sophisticated computer software to create it. Most people work in what is known as vector art. Software like Adobe Illustrator and Corel Draw are vector art programs. Some people use Photoshop although technically speaking that is for photography. If you know PS well enough you can do a lot of screen printing artwork with it. However, the most powerful art will be vector since you can buy volumes of clip art and templates which you can modify or manipulate. Try to learn either Illustrator or Corel Draw.
VIDEO: Tips On Software For Screen Printing Art
VIDEO: Vector Artwork Vs Bitmap Raster Images
VIDEO: Who Owns The Graphic Artwork And The Screens?
Artwork should be created specifically for the product it will be printed on. If the material is course and has texture, fine lines will not reproduce well. The bottom line is you need to know what you are doing here. If you are not sure do some research. The goal is to create a film positive of your art. This is simply a positive rendition of your art in black on a clear based transparent film. It could be anything from vellum to overhead transparencies. The most important thing of all when making your film is making sure it is dense enough. If the film is not 100% black in the artwork areas, then light will pass through it semi curing your emulsion which will cause it to be very difficult to wash out, if at all. The better your film is, the better your stencil will be on the screen and the easier it will be to make the screen.
The best film to use for the money is water proof inkjet film. This will be a milky cloudy film you can print in an inkjet printer like the Epson P400, P600, and the 15000. Common film sizes are 8.5x11, 11x17, and 13x19. Be sure not to get the film wet because despite the name it is not actually “water proof.”
VIDEO: Sizing Artwork For Different Tee Shirts & Pallets
There are a few different ways of reproducing artwork when you screen print tee shirts or any other garment. The different methods used will produce various results in color and print hand. It is important to have a decent understanding of the processes used as a screen printer. Even though you may not create the artwork, it will benefit you if you understand how the artwork is supposed to work. This starts with a basic understanding of the printing methods used to screen print. The following is a brief explanation of the individual types of artwork and printing methods.
Spot Color Printing: This is the most common form of screen printing tee shirts. This method uses the stock color of the ink without alterations by printing it through the stencil in wide open areas of the screen mesh. This will produce a very vibrant solid "spot" of color. It also tends to produce thicker layers of ink depending on the ink and the mesh count used. Printing in spot colors will be helpful in achieving opacity on darker garments. This is the least expensive to create artwork for and can also be very cost effective to print on 1 to 4 colors. When you begin to plan a design with 5 to 8 or more spot colors, a different printing method like simulated process may reduce the amount of film work and screen making needed to set up the job. Spot color artwork is great for most graphic logos that do not require gradients or excessive colors. (A spot and dot combine a one color halftone art with spot color art.)
Half-Tone Printing: This process involves printing single or multiple color designs with gradients. Here we can take a single color of ink and make it appear as two shades or more of the same color. These tones can range all the way from a solid spot to a very fine halftone of the same color. Sometimes referred to as a "spot and dot" this method is great when you want to achieve the look of multi-color printing without the expense of doing it. For instance, if we print red on a white shirt and include a 50% gradient of the red, the 50% gradient will "mix" with the white of the tee shirt giving the appearance of a pink color. Therefore, giving us a print with red and pink but only using one screen and one color of ink. If your graphic artist knows what they are doing, you can use this technique to improve the look and quality of your graphics. It is a great effect that will reduce the number of spot colors and screens. Printing in halftones will also produce a softer feeling print when printed directly onto the garment.
Gray scale Printing: This is a simple way of printing full color images as 1 color gray scales or halftones. Full tone color photographs may be printed as a 1 color halftone. Full color drawings or paintings that contain complete tonal ranges in different colors may also be reproduced by means of a 1 color halftone. Most often these are done in black ink on a light-colored garment. But single-color halftones may be done in any color ink if so desired. Many of us are familiar with the black and white printed images we see in many newspapers. This is a similar method used for printing 1 color halftones onto tee shirts. Resolution or image clarity will depend on the lines per inch used in the dot pattern. The more dots a halftone has the more detailed and crisp it will look. This is a great method for inexpensively printing black and white or full color photographs onto garments. Best results are achieved on white tee shirts. This will also produce a softer feeling print when printed directly onto the garment.
Duo-tone Printing: This is simply the combination of two halftones for the same image printed with 2 colors. Meaning there is the black halftone printed with black ink and then we will have a second halftone which will be printed with a color ink like a warm brown for instance. The warm brown halftone combines with the black halftone which will create a duo-tone print which has the color hue of the warm brown halftone. This is like a sepia toned print in photography. This is a very cool effect to print on light garments creating the feel of a full color print but being much less expensive to do. It also has a sophisticated, artsy look. This will also produce a softer feeling print when printed directly onto the garment.
4-Color Process Or CMYK Printing: This is probably the most complex of the printing processes and is recommended for automatic presses only. Although it may be done on a manual printing press, optimum and consistent results will be achieved only on a fully automatic tee shirt press. Here we take a full color photograph or image and break it down into its four constituent colors; cyan, magenta, yellow, and black. The printing process uses these four colors combined to recreate the full tonal and color range of the original image. Each color printer is a halftone of the opposite color in the original image. This system is based on what light is being absorbed.
VIDEO: What Is The Key or “K” Printer Or Plate?
This is so that the amount of any color showing in the final print will depend on the amount of ink laid down for each or the 3 primary colors. Cyan is the opposite of red. Magenta is the opposite of green. Yellow is the opposite of blue. The amount of blue in the final print will be directly related to the amount of yellow ink that is printed. The same is the case for the other primaries respectively. This is the most expensive process especially on dark garments. Only four-color process printing done by lithography or similar printing processes create the traditional "rosebud" associated with process printing.
CMYK printing on a tee shirt is more like simulated process in that spot colors may also be used and the dot pattern differs from that of traditional process printing where the colors perceived are mixed more in the brain rather than in the print. This will also produce a softer feeling print when printed directly onto the garment.
Simulated Process Printing: This combines standard 4 color process printing with spot color printing. This may also be done by printing spot colors with halftone colors which combine to create the colors of the original image. Here we use spot colors to intensify the overall look of the printed shirt. This may also be done when 4 color process printing is unable to reproduce a color the customer wishes to be dominant on the final print. As many spot colors may be added as needed but limited additions are recommended. This process can be more expensive than process printing because it can require complex artwork and the addition of many screens. This is most often the process used to print complex images onto black colored garments. It can produce some excellent imagery but requires some experience in artwork creation. The feel of this print will depend on the artwork and the under base if printed on black shirts.
Index Color Separations: There are different ways to handle index separations. This can be a simple way of breaking down a complex image into a few basic colors chosen from the original palate in the artwork. It can be difficult to do properly especially when the original image has a lot of different colors. For example, out of 10 colors in an image we may take 6 of them to represent the entire image with a posterization type halftone effect. It is not really a halftone but a diffusion dither random pattern. It can use stochastic square dots of equal size instead of elliptical halftones for instance. Obviously, this eliminates any possible Moiré patterns. You can also use the expanded color pallet with index separations. Therefore, sometimes an index separation will need at least 6 colors to do properly and in fact more colors can result in a better print. But usually in screen printing we want to minimize colors to minimize the set-up time.
Remember, for every color you wish to print, you will need a separate screen. Multi-color artwork is separated into different "printers,” “plates,” or screens. If your design has three colors, there will be three pieces of film and three screens made from them. Each screen will print a different part of the design in its respective color.
Halftone Printing: General Recommendations & Guidelines
This aspect of screen printing can get technical and become laden with unfamiliar terminology. Yet there is some very basic information we can relay without becoming too technical. However, a thorough knowledge of screen printing and art set up is needed to fully grasp this information to achieve good results.
Here are some general recommendations for working with halftones in screen printing. A fundamental necessity for great halftones is high quality film positives. It is an absolute must that the halftone dots are completely opaque.
VIDEO: What Are Halftones Vs Spot Colors?
Some points to remember:
- Large areas of the same color or dark areas will be the most likely to cause moiré patterns
- Use stable, metal frames of the same dimensions
- Use the same mesh on all the screens
- Stretch all the frames with the same procedure and tension
- Use very sharp, clean edged squeegees
- Try to use high viscosity inks with halftones
|
Ink Type |
Halftone LPI |
Mesh Count |
Thread Diameter |
|
Solvent |
Up to 120 dots/inch |
305 - 420 |
27, 31 and 34 |
|
UV |
Up to 150 dots/inch |
355 - 460 |
27, 31 and 34 |
|
Water Based |
Up to 120 dots/inch |
355 - 460 |
27 and 31 |
|
Plastisol |
Up to 90 dots/inch |
230 - 355 |
48, 40, 38, and 31 |
When making film, angling artwork controls the moiré pattern created between the halftone lines of each individual color film separation.
Halftone angling may be given in two ways:
- Within 90 degrees for rulings with two axes of symmetry such as checkerboard & dot rulings. This would be for round dots or squared dot patterns.
- Within 180 degrees for rulings with one axis of symmetry such as bead rulings. This would be for elliptical dot patterns.
- Colors like cyan, magenta, and black should be at an angle of 30 degrees from one another. Yellow, being a weaker color, can be set at a 15-degree angle from a darker color.
For images with high black content and deep tones:
|
Process Ink Color |
Within 90 Degrees |
Within 180 Degrees |
|
Yellow |
0 degrees |
0 degrees |
|
Magenta |
15 degrees |
15 degrees |
|
Cyan |
45 degrees |
75 degrees |
|
Black |
75 degrees |
135 degrees |
For images where yellow and magenta are dominant like in skin tones or orange colors:
|
Process Ink Color |
Within 90 Degrees |
Within 180 Degrees |
|
Yellow |
0 degrees |
0 degrees |
|
Magenta |
45 degrees |
135 degrees |
|
Cyan |
75 degrees |
75 degrees |
|
Black |
15 degrees |
15 degrees |
For images where yellow and cyan are dominant like in greens and water or aqua colors:
|
Process Ink Color |
Within 90 Degrees |
Within 180 Degrees |
|
Yellow |
0 degrees |
0 degrees |
|
Magenta |
15 degrees |
75 degrees |
|
Cyan |
45 degrees |
135 degrees |
|
Black |
75 degrees |
15 degrees |
The most dominant colors should be at 45 degrees, (within 90 degrees), and at 135 degrees, (within 180 degrees). For a one-color halftone the angles should be at 45 degrees for both dispositions of 90 and 180 degrees.
Be careful not to over flood the halftone screen on the flood stroke. Printing four color process, duo tones, and one-color halftones on a manual textile screen printing press can be challenging. Halftones are most often done on automatic machines due to their consistency and accuracy. Manually printing halftones takes the skilled hands of an experienced screen printer.
These are general guidelines. It is always recommended to check with your ink and mesh vendors as well as your graphic artist for specific instructions on creating film and screens for screen printing halftones. If you are unsure about the information or terminology used here, please consult a qualified graphic artist when creating your artwork and screens.
Here are some very basic introductory artwork videos using Adobe Illustrator. If you are using Corel Draw the concept will be the same while some of the tool names and/or functions may differ. However, both programs will have pretty much the same ability.
VIDEO: Basic Introduction To Artwork
VIDEO: Introduction To Illustrator
VIDEO: Working With Objects In Illustrator
VIDEO: Simple One Color Spot Designs
VIDEO: What Are Layers And How To Use Them
VIDEO: Working With Colors In Layers
VIDEO: How To Use A "T" Registration Mark
VIDEO: How To Use The Registration Swatch
VIDEO: Using Adobe Bridge & Clip Art
VIDEO: Converting Full Color Vector To Halftones
VIDEO: Reversing Line Art For White On Black
VIDEO: Host Based Color Separations in AI
VIDEO: Adobe Illustrator Distressed Or Textured Effect
Making The Film Positive
Outputting your film properly is a key factor in being able to produce an excellent stencil easily. If your film is not opaque enough, you will have trouble making a good stencil. Films that lack the opacity to block the exposure source 100% will end up semi curing the areas that you will need to wash out. Trying to wash out semi-cured emulsion is problematic for many reasons.
VIDEO: Doubling Up Your Film Positive For Density
It will take far longer in the washout booth to get the emulsion to completely wash out. This will cause the emulsion to become saturated with the water and possibly swell, wrinkle or details will wash out as well. If you try to underexpose your emulsion to compensate for inferior opacity in a film, saturation problems and loss of detail will become more apparent.
There are many output media available for printing your film from a computer. There are clear inkjet and laser films as well as laser vellum. Making an opaque piece of film at home with standard printers is a challenge. Most professional screen printers use Epson or Xanté printers with RIP software. RIP software is designed to make your computer and printer function ideally and output halftones or color separations. It controls the functions of the printer, in many cases, to output in only black. In some instances, you can replace color ink cartridges with all black. You can create your artwork normally in any graphic design program and send the file to the RIP software via the print function. From the RIP software, you will print the opaque film. Some RIP software will make the printer lay down a little more ink or toner than without it. RIP software is a must for any high volume, high quality commercial screen printer. But when you are starting out, you do not need RIP software unless you want to do automated color separations or halftones. You can create excellent film with a decent inkjet printer that can handle clear media.
Creating film positive is one of the steps that can be confusing and frustrating for home printers and beginners alike. The most important factor in making them is often overlooked. The principle of the film positive is to block the exposure source light from curing the emulsion during exposure. Therefore, film positives will work the best when they are opaque. Here is the thing. The emulsion used today is only responsive to UV light. It is blind to pretty much all other forms of light. Since using light to expose film is a photographic process, we can test the idea that emulsion only sees UV light by filtering the exposure source rather than blocking it.
VIDEO: Using Yellow And Red Inkjet Film Positives
It can be very difficult to print completely black inkjet or laser film positives at home without the proper films and software to control your printer. But there are several ways to make film positives that you should be aware of.
Inkjet Films - These are the type that can be printed in most standard inkjet printers. They are made of clear plastic film bases. Some may be water proof while other less expensive types are not. It is basically a piece of acetate with an “emulsion” coated on one side. That is the side you will want to print on since the emulsion is there to make the inkjet ink gel. Otherwise, it would run off the plastic acetate creating a mess.
Laser Films - This type of film is less popular most likely because density is very hard to control. Toner can only be controlled so much by printer settings and may be affected by toner cartridge age. They are made of clear plastic film bases. Distortion may be a problem in larger images due to the heat of the fuser.
Laser Vellum - This type of film positive is less popular most likely because density is very hard to control. Toner can only be controlled so much by printer settings and may be affected by toner cartridge age. This is a transparent paper product. This medium also has the disadvantage of possible shrinkage or wrinkling in the fuser. This can be a problem with multi colored jobs and their registration on press.
Thermal Films - These are films produced by means of a thermal printer. They are made of clear plastic film bases. This system can be much more expensive than inkjet or laser film producing processes. But the film is very high quality and always very dense. This produces very opaque film positives. You can have this type of film positive made for you for a fee.
Image Setter Film - This must be the absolute best way to produce film positives for screen making. They are made of clear plastic film bases. This is the system that replaced stat and process cameras when film positives were made using actual silver nitrate films and processed in a darkroom. But image setters are very, very expensive and most often only large print houses will have the demand for them. But you can often find such a print house in a city near you. You can have this type of film positive made for you for a fee.
Copier Transparencies - These must be the poorest of all film positives ever used for screen printing. They are made of clear plastic film bases. They are very poor quality in resolution and density. They often need to be doubled up to achieve the opacity required for screen making. The benefit to this method it that they are readily available at most copy stores.
Plotter Cut Vinyl On Clear Acetate - This is a home brew process that results in very opaque film positives. They are made of clear plastic film bases with plotter cut vinyl graphics applied to the film. These films are great to make especially if you are a sign maker and have a plotter with an odd color vinyl you want to get rid of. Most any color vinyl will block the exposure source but darker ones are best. The biggest drawback to this method it that you are limited to designs that can be made with a plotter and vinyl. That means no halftones or seriously thin, detailed lines.
This is a very brief rundown of the different types of film positives available for screen making. It is strongly suggested that you thoroughly do your research on the process that will best suit your individual printing needs. Depending on your end goals and desired results, you may be able to produce your own film positives at home very inexpensively.
VIDEO: Do I Need RIP Software & All Black Ink Systems?
An excellent water proof film positive is also necessary to getting great film positives with inkjet printers. Usually, inkjet film positives will be the most cost-effective way to produce the best quality film positives.
Some people will say that the film opacity is not so important because it is more about curing the emulsion that gets exposed. To me it is the same difference, just put a different way. The bottom line is opaque film makes screen making easy in any situation. Opaque film will make your life easier and allow you to teach anyone to make screens.
If your film positive is not as dense as you think it should be, check out these helpful videos about film:
VIDEO: How To Create The Best Spot Color Film Positives