ARTWORK FOR SCREEN PRINTING FUNDAMENTALS

Presented By Dane Clement

TYPES OF ARTWORK

Vector Artwork - Vector artwork is created using a series of points, or nodes, and outlines, or paths to create shapes which can then be filled or outlined with color. Each shape can be selected and modified individually. You can enlarge this type of artwork without effecting the sharpness of the image.

Raster Artwork - Raster artwork on the other hand is tonal artwork created by series of small dots or pixels. Photographs or painted illustrations would be examples of this type of art. You can’t select individual shapes like you can with vector art. This type of artwork is becoming more popular with the growth of digital printing. It’s not recommended to enlarge raster artwork. It can become blurry and pixelated if you enlarge it too much. The more it is enlarged, the more the image loses its sharpness and clarity.

Color Modes - Color modes are the different color models that can be used to create artwork. Some of the more popular modes are RGB, CMYK and greyscale.

RGB Color - images created using the combination of the values of the colors Red, Green and Blue. This is the mode used to produce image on a monitor. It is the color mode used when creating Simulated Process Color Separations.

CMYK Color - images created using the combination of the values of the colors Cyan, Magenta, Yellow and Black. This is the mode used for Four Color Process Printing.

Greyscale - images consisting of no color, only ranges of tones from black to white.

Spot Color - a single, specific color applied to individual, specific graphic items. It is the most popular form of screen printing. Each spot color requires its own screen.

WORKING WITH COLOR

5. Go to Image>Mode>Lab Color. Open your Channels palette and click on the Lightness channel to select it.

6. With the Lightness channel selected, go to Filter>Sharpen>Unsharp Mask. Move the amount slider to the right. We can really crank up the sharpness because we are only working with the luminosity of our image, not the color.

FILE OPTIMIZATION

Before any separating or printing takes place you want to make sure that your artwork has been set up properly for optimal printing. There are a few steps you should take to assure this.

1. In Photoshop go to Image>Adjustments>Selective Color. Change the “Colors” pop-down menu to “Neutrals” and change all the values to between 3-8.

2. Go to Image>Adjustments>Hue/Saturation and move the Saturation slider to the right. It can typically be moved to anywhere within the 0-45 range. Move it to the right as much as needed to saturate your colors without becoming over saturated and flat.

3. Go to Image> Adjustments>Brightness/Contrast, and move the Contrast to 5. If you have a newer version of Photoshop you will see a “Use Legacy” check box, be sure to check it on.

4. Next go to Image>Adjustments>Levels. Holding down your Option Key, move the black slider on the left side of the Input Levels to the right until you see black pixels show on your screen. Then move the white slider on the right side to the left until you see white pixels show on your screen. By doing this you are setting your black and white points in your image, and helping to reduce any “muddiness” in the colors of your layout.

TYPES OF SEPARATIONS

Simulated Process Separations - this process breaks down a full-color image into separate colors and uses halftones printed with specific spot colors to reproduce an image.

4-Color Process Separations - this process uses the 4 colors cyan, magenta, yellow and black to reproduce full color images.

Set Dot Gain to 36% and Total Ink Limit to 250%

Index Color Separations - this type of process creates images using 2 to 256 colors, thus the number of colors must be cut down to something manageable for printing on a press. It uses a dithered dot instead of the usual halftone dot.

ARTWORK PRE-PRODUCTION FUNDAMENTALS

Once you have your artwork done, there are some fundamentals you need to know about the pre-production process in order to properly set up your artwork and print your separations correctly for production.

Underbase - This is the initial color, usually white, printed on colored substrates in order to provide a light colored base for the additional colors to be printed on top of allowing the additional colors to be truer.

Blocker - This is an additional color that may occasionally be printed before the underbase to completely block the color of the shirt to prevent the dye migration of the shirt color from passing through and tinting the colors of the design.

Choke - This is the slight contraction of an underlying color such as the underbase or blocker to prevent it from peeking out from under the overlying color should registration be off slightly.

Manual Separations Using Color Range - the color range tool can be used to manually select specific colors in a design to create individual spot color separations.

Production Template - A preset document containing registration marks, greyscale bar and printing notations that can be used repeatedly to set up your separated file quicker and easier for printing.

Registration Marks - Registration marks are usually seen as a circle with cross hairs going through it. They are printed in the same position on each separation to assist with the alignment of colors when printing.

Grayscale Bar - Grayscale bars are a series of small squares filled with halftones of black usually in 10 percent increments. They are used in the production templates for screen printing to test how the different percentages of halftones are reproducing and to help keep printing consistent.

Butt Registration - Two colors are printed next to one another without any overlap or gap.

Trap Registration - When two colors are printed next to one another, one color has an overprinted stroke applied to it to create a slight overlap to help with registration when printing.

Gap Registration - Two colors are printed next to each other with a slight space between the two to allow for expansion of ink especially with the use of specialty inks.

Overprint - Underlying color will print out on a separation instead of being knocked out or eliminated by a color lying on top.

Knock Out - Elements of overlying color eliminate the same area of colors lying underneath.

Stroke - Outline of color set up along a shape. Often used in screen printing to create trap registration.

Halftone Screens - Halftones are a series of dots, lined up in rows set to a specific angle. They are used to reproduce images or create different percentages and shades of colors. We usually recommend a 45 lpi line screen, 61° angle, and elliptical shaped dots.

Line Screen - Also known as frequency, this is the component of a halftone screen determined by the number of dots per inch. The higher the line screen the more dots contained within the linear inch.

Screen Angle - This is the orientation of a halftone screen as measured from the horizontal axis. We do not recommend using a 45° angle as it can create an unsightly pattern in your image when printed called a moire.

Dot Shape - The shape of the dot used with halftone screens. The two most popular shapes used in screen printing are round and elliptical.

RIP Software - (Raster Image Processor) - software that interpolates artwork for printing on certain printers. Screen printing requires larger sized dots for reproducing halftone screens which many printers do not offer. This software takes the artwork information from the computer, reads it and then sends it to the printer to print the appropriate sized dot.

Once you’ve got the basics nailed down, start thinking beyond the fundamentals. How can you take your artwork and give it a twist or do something new to set yourself apart from others to steer customers to you? Here are some ideas to help get your creative juices flowing.

You don’t always need to go with the standard vector clip art images. Even when time and cost are a factor limiting you to a minimal amount of screens, there are ways to turn a full color image into a 1-3 color design and give your customer more bang for their buck.

BEYOND THE FUNDAMENTALS

Turn a full color design into a grayscale image and apply a large halftone dot to it and create a 1, 2 or 3 color design.

Use separations from a full color design, and select 1, 2 or 3 different colors to create a unique and intriguing layout.

Try adding distressed textures to your image for a more current and up-to-date look. Even a one color layout can become more appealing with the use of distressed textures.

Besides changes to the artwork itself, experiment with new printing techniques such as the use of discharge inks or specialty inks and foils. The examples below show how a single hornet design can be used and printed in a variety of ways.

1-Color Print with Distressed Texture 3-Color Print

Full Color Print - 5 Colors High Density Ink with Foil

1-Color Layout with Discharge Ink