Getting t-shirts printed is an ideal way to promote your business, organization or event. They are a promotional item that people can actually use, and they have the added bonus of being an advertisement for you. In this post, Adobe Illustrator will be used to create a three-color screen print using a fictional company logo, and have it set up to allow a screen printer to easily print the color separations that create the separate screens for each color print.
Although some printers prefer to create their own separations, it’s always good to understand the process. Be sure to communicate with your printer as they will specify their requirements, and will often give you tips for avoiding potential issues in the process.
Printing Techniques
As the t-shirt is going to be printed in three colors, we have to create separate artwork for each layer of color. Each of these layers interact with each other to form a complete image.
Examples of Trap, Knockout and Overprint
There are three artwork techniques commonly used for this type of printing: Trap, Knockout and Overprint. The Trap technique is when the bottom color “bleeds” under the top color, ensuring no gaps are left from inaccurate printing of the second color (when the so-called “registration” between the colors is “off”).
Screen printing is not always an exact printing technique, especially when printing onto fabric surfaces; for this reason the Knockout technique is rarely used, as it relies on printing a color precisely in a gap left on the bottom color. The third technique, Overprint, is the easiest to achieve as the top color prints directly on top of the bottom color; often this produces a new color, as the top ink color is not always opaque.
Preparing Your Artwork File
1. Create Layers for Each Color
The most reliable way to produce artwork for screen printing is to manually prepare it in Adobe Illustrator. Each of the three colors is going to form a separate artwork in a separate layer, using elements from the main image for each color. Using Layers does not affect how your artwork is output by your screen printer; it just makes it easier for you to work on.
Opening the vector artwork in Illustrator presents the graphic in Layer 1. Select the drop-down menu in the Layers window and select Duplicate Layer twice, to produce three layers of the same graphic; name the three layers after their respective colors, as this will help prevent confusion later on. Ensure the order of the colors is correct: the bottom layer is White; the next color layer is Orange; and the top layer is the Dark Red, which will be printed last, on top of the other colors.
Layers being created and renamed
2. Create a Temporary Background Color Layer
At this stage — because the artwork is being prepared to be printed on a dark t-shirt — create a fourth layer for a temporary background color and name it Temporary Background. A rectangle is drawn the full size of the art board, and given a dark color; this layer will be removed later in the process. Drag the layer to the bottom of the layers, and Lock it. Each color of your artwork produces a separate screen, and the order in which the colors are printed is usually from the lightest to the darkest color.
A Temporary Background layer is created
3. Remove Excess Objects From the Layer
The first layer to be worked on, is the bottom White layer. Hide the Orange and Dark Red layers by clicking the Eye icon next to their layers, and make sure the White layer is selected in the Layers window by clicking on its name. As the artwork layer was duplicated in full, all the objects of the graphic are on this layer; some objects must be removed, leaving the shapes that form the white outline of the rocket, the text, and the orange fan shapes used in the background.
4. Outline All Strokes
The rocket outline is a solid shape so no further work is needed on the rocket, but the white outline of the text is a thick stroke applied to the text shapes; working with strokes can be unpredictable, so it’s best to create outlines from the stroke by selecting the text and choosing Object ? Path ? Outline Stroke. This ensures consistency if the artwork needs to be resized (Strokes can often be pushed out of proportion when resized with the Scale tool).
Outline Stroke on text objects
5. Create and Apply a Custom Spot Color
Select all the objects in this layer and apply a light color to each of them. Avoid using absolute white, as you won’t be able to see the objects when checking Separations later. Apply a color of 20% Yellow to the objects and then, in the Swatches window, select New Swatch from the drop-down menu. Name the swatch “White base” and choose Spot Color from the Color Type menu. Even though it’s set to 20% yellow, it will output as a solid color, titled “White base.”
Creating a new Spot Color Swatch
The swatch now will be in the Swatches window and there will be a dot in the corner to denote a Spot color. The Spot color should be applied to all the objects in the White layer.
Potential mis-registration of two colours, seen between orange and dark red
Select an Orange object and choose Object ? Path ? Offset Path. Offset the path by 1 mm to make the object larger in shape. Oftentimes printers specify how much Trap they require, similar to how they might specify Bleed. On this artwork, the white background outlines the color objects, but if you wanted the white to be printed directly behind the colors, without a white outline, you could offset the path of the White objects by a minus figure (for example -1mm).
Reference: http://c.notify.me/qxlLBw
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