T-shirt Factory Blog

As you probably know, Illustrator works with vector format files, which is great in apparel/printing, because of the way vectors can scale infinitely, and also because of the automatic color separation option offered by Illustrator.

I am going to try and explain a method that allows raster files, such as photos or digital paintings to be easily converted into a vector format. There are several ways to do that, some take a lot of time, some are just as straightforward as clicking the live-trace button. The big difference is the result. A live trace will most likely produce an inaccurate result, too many colors or will just make everything look sloppy.
Today’s method of choice is through halftones. Why like that? First of all, you will get a one color vector shape that looks like a shaded picture. Also, this method produces quite the good-looking result that can be used in a lot of designs. So, it looks good and it results in a one color picture. Great, right?  Let’s do this!
First, you’ll need Adobe Photoshop and Adobe Illustrator for this. With PS we’ll convert a raster image into halftones, and with AI we’ll convert the result into vectors.
Open in PS your picture of choice. I choose this image which is not a particularly high res picture, but that is not a problem.
We need to isolate the turtle from the background. For this, use your selecting method of choice, I prefer the pen tool and then converting the paths lo a selection.

Here you can see the paths  and after completely selecting it, you use the convert to selection button in the paths tab. That would be the third button from the left

Now that you have the object selected, you copy it with ctrl+c and paste it on a new document with ctrl+v. Now, next step, convert to grayscale. (Image/Mode/Grayscale). You should have this:

Now comes the actual halftone-ing part. Again, Image/Mode/ and now choose Bitmap. Yes, flatten all layers and discard hidden layers. Now from the menu choose halftone screen and a resolution of 300dpi should work good enough
Next box, you have to choose some values. Play with them, you’ll understand how this works better. My choice is a 55/45/round. Don’t choose a very high frequency, as some printers might have a problem with that.

This is what you get at this point, in full size. Notice how if you zoom out, it kind of looks like a newspaper print picture. And yes, that is only two colors, black and white. Sweet, isn’t it?
Now it’s that special time of the tutorial, time to convert our raster. Copy what you got there. Open Illustrator. New file.  Now, paste the picture. Notice the Live trace button?
Push it. Now, about live trace: again I recommend playing with the presets and settings. That is the only way you’ll see what works for you. After pressing the Live Trace button, I tweaked the Min Area to 0. Again, test some values, see how that works.
My result is this:

Now, near the Min Area is the Expand button. Press it! Tadaa! Vector paths! Next, using the magic wand select the white in the image. Unlike PS, you just need to click on one white area. Now, press delete. Good, now you got yourself a black halftone vector of the image. One color, all ready to be expanded/contracted without quality loss.
You can select this image, change its color, and get creative! This is my result.

Remember, keep playing with the settings, do it your way - that is the only way you’ll learn how to do it!