Designer Tutorials and Tips For T-Shirt Printing Toolkit

July 8th, 2009 by tim / Comment on this post

In the past year I’ve learned quite a few things that I didn’t know about t-shirts, and t-shirt printing that I thought I would share with anyone who’s either already designing their own shirts, or just getting started.

If you’re printing your shirts using a direct to garment type of solution you need not worry about many of these tips such as reducing the colors, but for those of you using screen printing, like we are at Assault Shirts, I think you’ll find most of these tips and resources very helpful.

Reducing image colors in preparation for a screen printing in Photoshop

Throughout many of our t-shirt designs we’ve had to reduce the amount of colors in an image in order to make it fit into the color scheme of our design.

Reducing the amount of colors also makes it cheaper to print, and it gives you a better idea of what your design is going to look like once it’s been screen printed. We used this technique in our 1984 T-Shirt design as well as our One Year As A Lion T-Shirt. The key to reducing an image’s amount of colors for screen printing is the Posterize image adjustment. To demonstrate, I’ll use this image of Johnny Depp as the iconic Chicago gangster, John Dillinger.

Image > Adjustments > Posterize…

Posterize reduces the amount of colors in your image to the number of levels you specify. Depending on what kind of a look you are going for you can reduce the amount of colors once, or sometimes twice to get the desired look for your image. I’m sure you can even reduce it further, but I generally use 3 or 4 levels.

To posterize your image, first make sure you are on the selected layer you want to posterize. Then, go to Image> Adjustments> Posterize…

After posterizing your image, you can either desaturate it or try varying the amount of levels within the Posterize settings to get the desired effect. Here’s a few other options I managed to come up with:

You can also bring your image into Illustrator, and start to trace the image so it doesn’t look so crispy which you’ll find may have a better effect than what I’ve outlined above. I personally am all-Photoshop guy so I prefer to keep everything in Photoshop, but Live Trace in Illustrator is another popular method for vectorizing an image.

New Document Presets for Screen Printing T-Shirts

The two document presets for the two sizes of screens that we use are:

oversize t-shirt screen preset photoshop

18x23 canvas with 300 dpi resolution in CMYK color mode

With the large image sizes it may make sense to start at a resolution of 150dpi if the computer you are working on is a bit older. You can also use a Fill Layer for a background rather than a raster background layer to reduce your document file size. I do this with all my designs so my working file isn’t a 2gb fail whale waiting to happen.

Getting Pantone color codes for exact color matches with your printer

In order to guarantee your designs colors are matching and actually printable you need to send your pantone colors for every color in your design to your printer. Rather than let them do the color work for you, you should send the colors pantone codes.

To do this, use the eye-dropper tool by selecting it in the tool palette or by hitting the “i” key and then clicking on the color in the design.

After you have the color selected, in your tool palette double click the color, and your color picker will open with the color you just eye dropped. Generally, this color will still be an RGB or CMYK color and isn’t the pantone color code we want. To get the approximate pantone color code, click on the “color libraries” button.

This will open up your color libraries window and the eye dropped color should be selected. The P542 C is what you want to send to the printer along with every other color code associated with your design.

2 minute color separation in Photoshop

Our printers have always done the color separation for us after we send them the high resolution images, but in case you need to do color separation on your own here’s the easiest and quickest way to accomplish that:

Select the Magic Wand Tool in the tool palette (or hit the “w” key”)
Uncheck “Contiguous” in the tool options area

Click a color on your design

Select a color on your design

Create a new layer and fill it by hitting cntrl + backspace or alt + backspace (depending on what color you want to fill it with the foreground or background)
Repeat this for each color in your design and you should have each color separated on it’s own layer! (Here’s my design with new colors all separated on their own layers below)

color separation photoshop

I also found several detailed step by step Youtube videos which outline the above process using similar techniques:

T-Shirt placement templates and mock ups

To ensure your printer gets your shirt printed with the correct shirt placement you should place your design on an actual shirt. This should be included with your high resolution shirt files that you send to your printer.

In the past we’ve used a combination of the below sources for t-shirt templates and mockups:

Photoshop T-Shirt Custom Shape -- Download Use this custom shape as a background and place your shirt design atop it and mask out the outside area.
Go Media’s Arsenal T-Shirt Templates are a the best way to get a photo realistic idea of what your designs will look like. They’re worth every penny.
Color Overload’s Men’s T-Shirt Templates Another PSD with an assortment of color t-shirt templates to use for creating mockups from Color Overload
Assault Shirts Product Page Photoshop Mockups This is our T-Shirt mock-up that we use on our product pages at Assault Shirts. It’s my personal favorite and can be used for shirts of all colors in the American Apparel style.