I don't use Photoshop or Illustrator. But, as a DIY songwriter/performer, I still need to be able to create merchandise.
And in order to create merchandise, you need transparent images.
What is a transparent image?
It is an image that contains a later without any pixels - only information allowing whatever is behind the image to show through. For instance, if you have a yellow shirt and want text over that shirt, you need an image that contains just the text, not the area that border the text.
A transparent image contains the information necessary to print text and images without including non-printing sections. Here is an example from the video tutorial below.
A shirt with a non-transparent image
A shirt with a transparent image
Note that the image in the 2nd shirt displays the shirt color except where there is actual text and the puppy image. But, if you were looking at the shape of both images, both would still be square/rectangular. It is just that the non-printing elements have a transparency layer.
About file types
jpg/jpeg files do not allow for transparency. They are not an effective format for creating merchandise.
Video Tutorial: Transparent Images with Microsoft Publisher
A few tips or things to consider
- Change your publisher file size to the approximate size you are printing.
For shirts this is often 10"X10" or thereabouts. 8" X 8" is probably fine. Even if sized up or down, it is fairly close. Your shirt printer should be able to give you some guidance.
- Test your .png by bringing it back into Publisher over a rectangular colored background. That will let you know that the transparency worked properly.
- In publisher, duplicate a page by right mouse clicking on the page thumbnail on the left side and select, "Duplicate page". Maintain older iterations until you are happy with your new design.