Somebody sends us their artwork that they would like printed out onto T shirts.
How is it done?
Follow me into the studio…

We get artwork in a whole variety of forms from finalised vector graphics to a quick sketch on a shopping list.
For this demonstration, I will use a sketch of Woody Allen put together in photoshop.

To start with, this has a wide variety of textures and is fairly colourful. The idea here, is to produce a stark, single colour print. Woody’s going to need simplifying and that means combining all the tonal areas into black.

One way is to adjust the levels (image/adjustments/levels), another way – and the one I have used here – is simply to pull the contrast up and the brightness down. When you’re happy, save the file.
For screening simple graphics like this, as with so many other things, vector is best. Vectorising a piece of bitmap artwork will give it ultra crisp lines instead of the blocky edges we associate with bitmaps.
Open up illustrator or another vector program, and take the image into it.
You can draw over the sketch using the pencil tool. This way, you can do some cleaning up of the lines as you go.
However, if it’s speed you’re after, you should always try vector tracing first. As well as, usually, making a very good job of it, tracing often introduces interesting and useful effects of it’s own.

Here we have the bitmap sketch (on the left) and a quick trace using the default live trace setting in illustrator.
Even at this size, you can see how a lot of the messiness has been cleaned up by the simplifying action of a vector trace.

If we go in closer, the difference in line edge clarity is obvious. This will print nice and cleanly.

It could well be argued though, that some of Woody’s character is lost – look particularly around the mouth where the shadow has become decidedly angular.
Here’s where the tracing variables can help.

This time, I’ve gone into the options and taken the path fitting down to 1 pixel. This gives a trace with a much higher fidelity to the original image. Too far in this direction, however, can result in the actual bitmap pixels being traced! If the original is of a low resolution this can happen, and will result in something which is still rough looking. You should make sure that your original image is of a good resolution to start with if possible.

Another setting which can make all the difference is blur. Using this tool can turn ragged lines into smooth, flowing ones which tend to look quite organic. For simple shapes particularly of an abstract nature, curlicues and the sort of floral patterns commonly seen in artwork today, this might be just the job. Also the blurring of a trace can impart a ‘glossiness’, or sort of plastic sheen etc. Depends what you have in mind.

Here’s Woody again with the blur turned up to 4 px. It’s often a trade-off, trial and error, but again, the higher quality the original artwork the better.

However, we have to try and work with what we receive and often all we have is a low quality piece of artwork. Tracing does not always work. Under these circumstances, we have to re-draw, and a drawing tablet, such as a Wacom can work wonders – so much easier than using the old mouse.

Related posts:

1. T- shirt design:Creating simplified artwork from a photograph
2. 5 colour index separation and waterbased ink
3. 6 Great Sites for Vector Resources and Tutorials
4. 6 colour T shirt print, index separation
5. Index Separation Method for Screen Printing