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Illustration

Create a Three-Color Illustration for Screen Printing

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This tutorial shows step-by-step how to create separated artwork for a screen printed T-shirt. Screen printing is regarded as the best method of printing onto apparel because of the quality it produces – and should not be confused with the inferior 4-color heat transfer printing which does not look as good or last as long.

The tutorial also demystifies how to manage special or spot colors using Photoshop's channels.

To start off, you'll assemble a CMYK illustration, then create a convincing mock up on a T-shirt. You'll then make full use of Photoshop's selection tools to create the necessary channels for screen printing, then discover how certain colors will maintain their vivacity by under printing with white. Finally, you'll apply the often misunderstood concept of trapping to your artwork to counteract any slight misalignment that may occur on press.


Step 1

Download and open the girl image, you'll be isolating the figure next, so trim the excess background with the Crop Tool (C) as shown.



Step 2

Choose the Pen Tool (P) with it set to the Paths option to carefully plot your paths around the girl – don't sweat over the hair, you'll fix that later. I've stroked the path with red for clarity in the screengrab. Now select the Subtract From Path Area option to create the inner path on her right arm.

Remember to use the Alt, Command and Shift modifier keys as you work. You can also fine-tune your path by holding the Command key to access the Direct Selection Tool to adjust the direction/anchor points.



Step 3

Now we'll make a density mask for the hair. Switch to the channels palette and cycle through each one in turn to determine which holds the most contrast for the hair – in this instance it's the "Blue" one. Duplicate it by dragging its thumbnail onto the Create New Channel icon, then hit Command + L to access the Levels dialogue box. Increase the contrast by setting the midpoint to 0.25 and the whitepoint to 235.



Step 4

Switch to the paths palette and Command-click your path thumbnail to generate a selection. Now back in your channels palette, target the "Blue copy." Ensure white is set as your foreground color, then hit Delete to fill the selection with black. Don't deselect just yet.

It's worth remembering that you can fill channel selections with white by switching the foreground color to black (press X) and hitting Delete.



Step 5

The mask is looking good apart from the right-hand shadow. Hit Shift+ Command + I to Inverse the selection, then enable the visibility of the top composite channel (you can also double-click the channel thumbnail to adjust its opacity to suit), then use a large, hard-edged white brush to erase the right-hand shadow and hair.



Step 6

Zoom in and continue erasing the hair using a smaller brush to create a clean edge. Remember to toggle the visibility of the composite channel as you work.



Step 7

Now go to Image > Adjustments > Black and White and use the drop-down menu to select the High Contrast Red Filter preset.



Step 8

Switch to the channels palette and Command-click the "Blue copy" thumbnail to generate a selection. Inverse, then target the top composite channel and Copy it to the clipboard, now use the Color Picker to select 63C, 76M, 38Y, and 22K as your background color. Create a new document 7.5" wide by 12" high; with a resolution of 300dpi (print resolution); set the Color Mode to CMYK and set the Background Contents to Background Color.

Now Paste your selection as a new layer, then go to Layer > Matting > Defringe by 2px to erase the white halo and Transform/position as shown. This purple background is only a visual representation of the T-shirt color.



Step 9

Generate a selection from the layer by Command-clicking its thumbnail, then switch to the channels palette. Click on the Create New Channel icon and then fill the selection with white, labeling it "Girl Alpha." It's always a good idea to store commonly used selections as alpha channels, as you'll see later.



Step 10

Screen inks tend to spread a little – this is one of the reasons why screen printing doesn't do a very good job of printing fine halftones, at least compared to other printing methods. When dots increase in size they cause the tints in the image to grow darker which is technically known as dot gain.

To combat this we'll integrate a coarse line halftone to the girl as part of the design, but first we need to bump the contrast by adding a Levels adjustment; setting the blackpoint to 64, the midpoint to 0.88 and the whitepoint to 216.



Step 11

Add a new white filled layer below the girl, highlight both layers and hit Command + E to Merge them. We now need to make a bitmap halftone of the girl – the best way to achieve this is in a new document, so Select All and Copy to the clipboard.



Step 12

Create the new document using the clipboard as the preset and setting the Color Mode to Greyscale. Paste your selection and Merge Down. Now go to Image > Mode > Bitmap, then under Method choose Halftone Screen. In the next dialogue box use the following settings: Frequency: 22, Angle: 45, and Shape: Line.



Step 13

Select All and Copy > Paste into your working document and label it "Girl lineart." Next, set the Blending Mode to Multiply and Delete the original girl layer.



Step 14

Make a selection from the "Girl Alpha" channel, add a new layer beneath the girl and fill the selection with white. Label the layer "White fill." Now place the "Girl lineart" and "White fill" layers into a group folder labelled "GIRL."



Step 15

We're now going to fill the girl's shirt and shoes with pink; first draw some closed paths (indicated in red on the screengrab) that extend outside the figure as shown – you'll be using the extra channel to fix these areas next.



Step 16

Click on your foreground color to access the Color Picker, then select Color Libraries. In the next dialogue box select PANTONE solid uncoated, then PANTONE 238 – rather than using the slider, you can access it by typing 238 swiftly. We'll be using this four-color equivalent to create the CMYK illustration before using the spot color channels in the final steps.

Generate a path-based selection, add a new layer above the "White fill" and label it "Pink clothes." Now fill the selection with the foreground color. Next, make a selection from the "Girl Alpha" channel, ensure the new layer is targeted, Inverse and hit Delete to trim away the excess.



Step 17

Open "Brushstroke_1.jpg" from the "source" folder and choose the Magic Wand Tool (W), setting the Tolerance to 44 and unchecking the Contiguous option. Now click within the black area to generate a selection, fill with white and Copy to the clipboard. Close, but don't save the file – as you'll be needing it later.



Step 18

Add a new group folder within you're working document below the Girl and label it "WHITE GRAPHICS." Paste the selection within the folder, label it "Paint 1" and transform/position as shown. Follow the same procedure using "Brushstroke_2.jpg," then feel free to duplicate/transform and label accordingly.

You'll be Pasting a lot of elements throughout this tutorial – so remember to use the Defringe command, a setting of 1-2 pixels is usually enough to remove any white halo.



Step 19

Add a new group folder below the Girl and label it "PINK GRAPHICS." Open "Lines_1.jpg" from the "source" folder and convert to CMYK mode, then use the same selection techniques to fill with PANTONE 238.

Now Copy > Paste into the new group folder, Transform/position as shown and label it "Squiggle 1." You can now close "Lines_1.jpg" without saving.



Step 20

Paste "Lines_2.jpg" from the "source" folder using the same method. Feel free to duplicate and Transform as required. Next, open "Spray.jpg" from the "source" folder and use the same technique again, positioning it behind the figure. Remember to name your layers – this will make things much easier later.



Step 21

With PANTONE 238 as your foreground color, use the Custom Shape Tool (U) with the Ellipse and Fill pixels options selected to add some circles behind the girl. When using the Fill pixels option, you need to add a new layer beforehand, so the shapes will be drawn on independent layers. This way they can be positioned and re-sized as required.



Step 22

Create a new 600px by 600px sized CMYK document, with a Resolution of 300dpi and the Background Contents set to Transparent. We now need to add some central guides; a quick way to do this is work in Full Screen Mode, then snap the Crop Tool (C) to the document bounds. Now drag in your guides which will snap to the Crop Tool's centre points, then cancel the crop prompt.

Next, make sure PANTONE 238 is set as the foreground color. Select the Custom Shape Tool using the Ellipse and Fill pixels options as previous. Use the drop-down menu to select Fixed Size and type 550px in the Width and Height fields, then check the From Center option. Now click in the centre of your canvas to create the shape.



Step 23

Switch white to your foreground color and add another circle set to 500px by 500px on the same layer. Continue adding alternating color circles, each one decreasing in size by 50px. When you've completed the last white circle, use the Magic Wand Tool (set to Contiguous) to select it and hit Delete.



Step 24

Drag and drop the graphic at the top of the layer stack within the "PINK GRAPHICS" folder. Next, duplicate, re-size and position as required. Feel free to add variations of the circles (I created a version with a pink fill). When you're happy highlight their layer thumbnails and Merge. You can now label the resulting layer "Bullseyes."



Step 25

Open "Brushstroke_2.jpg" again and convert it to CMYK mode. Fill with PANTONE 238 and Copy > Paste at the top of the layer stack within the "PINK GRAPHICS" folder.



Step 26

Follow the same techniques for "Flower_1.jpg" and "Flower_2.jpg" and position as shown.



Step 27

Now open the Line files again and use the same selection techniques to Copy > Paste into a new group folder labelled "BLACK GRAPHICS." Ensure this folder is positioned above the "PINK GRAPHICS" folder.



Step 28

Open the "Spray.jpg" file again, make a selection and Copy > Paste at the top of the stack within the "BLACK GRAPHICS" folder and position behind the girl as shown.



Step 29

Use the same method to add the remaining hand-drawn elements from the "source" folder ("Star_1.jpg," "Star_2.jpg," and "Cloud.jpg").



Step 30

Download and open the birds image, select the birds with the Magic Wand Tool (with Contiguous unchecked) and Copy > Paste at the top of the layer stack within the "BLACK GRAPHICS" folder. Now re-size and position to the left – also feel free to delete individual birds with the Eraser Tool (E).

Next, generate a selection from the "Bullseyes" layer and with the "BLACK GRAPHICS" folder targeted, go Layer > Layer Mask > Hide Selection.



Step 31

Add a new layer at the top in the "BLACK GRAPHICS" folder, then draw a black circle as shown with the Elliptical Custom Shape Tool (using Fill pixels). Next, open "Splash.jpg" from the "source" folder and use the Magic Wand Tool (with Contiguous unchecked) to select, Copy > Paste above the circle later, then transform/position and Merge Down.



Step 32

Open "Lettering.psd" from the source folder and drag/drop above the circle. Then add a PANTONE 238 heart on a new layer using the Custom Shape Tool (set to Fill pixels). Now's the time to scrutinize your image and carry out any amendments: I added some small white circles on a new layer within the "WHITE GRAPHICS" folder. Once you're happy, save but don't close it.



Step 33

Now we'll mock the finished design onto a T-shirt. I drew inspiration from this Go Media tutorial.

Download, open the wood image, then go Image > Rotate Canvas > 90 degrees CW. Next, create a new 300dpi, RGB document 10cm by 10cm, then drag/drop the wood as a new layer, Transform and Merge Down.



Step 34

Download and open the T-shirts, we only require the bottom left one, so crop it . You'll notice there's already a clipping path supplied, so make a selection and Copy > Paste as a new layer in your working document. Give it some depth by adding a Drop Shadow. I used a the following settings: Blending Mode: Multiply, Opacity: 75, Angle: 50, Distance 6, and Size: 21.



Step 35

To alter the T-shirt color; click the Create new fill or adjustment layer icon and use the drop-down menu to select Color Fill, then pick the same purple used in your CMYK illustration (63C, 76M, 38Y and 22K). Don't worry about this altering the color of the wood – we'll fix that later.



Step 36

Back in your CMYK illustration access the History palette (Window > History) and use the pull-out menu to create a New Snapshot. Delete the purple background layer and target the "Girl lineart" layer.

Next, use the Magic Wand Tool (set to Contiguous) to select the white background (it's there, just not visible because the layer's Blending Mode is set to Multiply) and hit Delete. Finally, press Shift + Command + E to Merge Visible.



Step 37

Drag/drop the resulting layer into your T-shirt document above the Color fill, and label it "Illustration." Re-size to fit the T-shirt – this is best done in stages and adding small amounts of Smart Blur each time to retain the sharpness. Now switch to your CMYK illustration and click on the Snapshot you created in the previous step to restore its saved state.



Step 38

To make the print look realistic, duplicate the T-shirt layer and position it at the top of the layer stack and label it "T-shirt multiply." Now set the Blending Mode to Multiply and drop the Opacity to 70%.



Step 39

Target the T-shirt multiply layer and Alt-click between the Illustration, Color fill and the original T-shirt layer icons to create a clipping group. This has now made the non-transparent areas of the uppermost layer serve as a mask for the clipped layers. Because clipping groups use one mask, there is no edge interference from underlying layers.



Step 40

As a finishing touch drop in the original illustration at full size above the "Wood" layer. Duplicate and position either edge of the canvas. Now set both layers' Blending Mode to Soft Light so as not to overpower the illustration.



Step 41

That's the T-shirt mock up complete. Remember it's also very quick to visualize how your design will look on different colored material by simply adding Color Fill Adjustment layers and toggling their visibility. Your screen printer will also be able to supply various material swatches – so it's just a case of matching them on-screen.



Step 42

In the final part of this tutorial you'll be creating the artwork for screen printing. Revisit your CMYK illustration and hit Shift + Command + S to Save As, giving it a memorable name such as "Spot_col_artwork."

The white ink will be printed first, followed by the pink and then the black. To optimize the pink ink, it's best to add white beneath it. Sometimes your printer will add a double pass of white ink, depending on the darkness of the material being printed. The thing to bear in mind is you need to build in a certain amount of trapping to these white areas. This means contracting (choking) or expanding (spreading) areas to compensate for any slight shift which may occur when the T-shirt is printed. The diagram bottom left shows what may happen with no trapping, as you can see the T-shirt material is showing through. You'll learn more about this later.



Step 43

Disable the visibility of all folders except for the "WHITE GRAPHICS" folder and the colored "Background" layer. With the "WHITE GRAPHICS" folder targeted hit Command + E to Merge Group.



Step 44

Generate a selection from the resulting layer and switch to the channels palette. Use the fly-out menu to select New Spot Channel, label it "White" and then click the Color swatch to access the Color Picker. Now set the CMYK values to 0 and click OK – the active selection will now appear as black on the new channel.

You'll notice that by toggling the visibility of the "CMYK" composite channel the "White" channel appears either black or white which is correct - all artwork on spot channels is represented in black, regardless of its' actual printing color.



Step 45

Move the "Bullseyes" layer out of the "PINK GRAPHICS" folder so it sits beneath the "BLACK GRAPHICS" folder, then Merge the "PINK GRAPHICS" folder. We now need to add this layer content to the "White" channel – but first we need to choke or shrink it. Most printers work in points and I was given a trap value of half a point (0.5pt), different printers' trap requirements will vary, so it's vital to check beforehand.

Here's a little equation to convert points into pixels: There's 72 points to an inch, so to find out how many half points there are to the inch, divide 72 by 0.5, which equals 144. Now divide the document resolution, (which is 300) by 144 which makes a trap value of 2.

Generate a selection from the merged pink layer and go Select > Modify > Contract by 2px. Now target the "White" channel and fill the selection with black.



Step 46

Generate a selection from the "Bullseyes" layer, Contract by 2px, then fill the active selection with black on the "White" channel. Next, generate a selection from the "Girl Alpha" channel and fill with black on the "White" channel also.



Step 47

Make a selection from the "Pink clothes" layer, Contract by 2px and then Inverse. Now pick a small, hard-edged, white bush and carefully paint out the outer shoe edges on the "White" channel.



Step 48

Generate a selection from the "Lettering" layer and Expand by 2px. Now fill this with black on the "White" channel. Do the same using an Expanded selection from the "Heart" layer. These areas are now spread, to run fractionally behind the black circle.



Step 49

Make a selection from the merged "Pink graphics" layer, then add another spot channel. Select PANTONE 238 as you did in Step 16 and label it "PANTONE 238." The active selection will now appear as black on the new channel – you can check this by disabling the visibility of the "White" channel.



Step 50

Generate a selection from the "Bullseyes" layer and fill with white on the "PANTONE 238" channel.



Step 51

Zoom in and use the Magic Wand Tool (with Contiguous unchecked) to select just the pink areas from the "Bullseyes" layer. You'll need to have the visibility of the "Bullseyes" layer as well as the composite "CMYK" channel targeted to do this. Now fill this selection with black on the "PANTONE 238" channel.



Step 52

Fill a selection from the "Girl Alpha" channel with white on the "PANTONE 238" channel.



Step 53

Now fill a selection from the "Pink clothes" layer with black on the "PANTONE 238" channel.



Step 54

Generate a selection from the "Heart" layer, this area needs spreading behind the black circle: So Expand by 2px and fill with black on the "PANTONE 238" channel.



Step 55

Merge the "BLACK GRAPHICS" folder and generate a selection. Add another spot channel, label it "Black," then click the Color swatch to access the Color Picker. Set the CMYK values to 70c, 70m, 100k – using a CMYK setting for spot black ink will not affect the ink color, it's only an on-screen representation and as long as your channels are clearly labelled that's all that matters.

The active selection should now be filled with black on the new channel. Next, fill the "Black" channel with white using a selection from the "Bullseyes" layer.



Step 56

Now fill the "Black" channel with white using a selection from the "Girl Alpha" channel. As the black ink overprints print last, there's no need to apply any trapping.



Step 57

Fill a selection from the "Circle" layer with black on the "Black" channel. Now make a selection from the "Lettering" layer and fill with white. Repeat using a selection from the "Heart" layer.



Step 58

Generate a selection from the "Girl Alpha" channel, then target the "Black" channel. Now use a hard-edged, white brush and paint within the selection to reveal her left leg.



Step 59

Now use the Magic Wand Tool (with Contiguous unchecked) to make a selection of the black areas on the "Girl lineart" layer. Now fill with black on your "Black" channel.



Step 60

You can check the trapping by enabling the visibility of the three spot channels, then zooming in to 200%. Now generate selections from your "White" and "PANTONE 238" channels in turn. The screengrab below shows a selection from the "White" channel – the white lettering and the base white (under the pink heart) have both been spread under the black.



Step 61

All you need do now is enable the "CMYK" composite channel and Delete all your layers apart from the background – which you can rename "T-shirt color." Finally, Save – ensuring to check the Spot Color option and that's it, your PSD file is good to go.



Conclusion

I Hope this tutorial has cleared up some common misconceptions a lot of designers have using spot colors for screen printing, as well as how and when to apply trapping to your artwork. I would like to credit my daughter Chloe for drawing the doodles, as well as a big thanks to Steve at Advertees who always offers great technical support, and for casting his expert eye over my final artwork to ensure it was error free!

If this has inspired you to make your own T-shirt designs, remember it's good practice to involve your printer at the initial design stage to see what's achievable. Have fun!

The final image is below. You can view the large version here.



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