There are a few things to consider when deciding where to place a design on a shirt. The first is the size of the design. If the design is large, it may not fit well on the chest or back of the shirt. It is important to test the placement of the design on a shirt before printing it. Another consideration is the color of the shirt. If the shirt is a light color, the design will be more visible on the front of the shirt. If the shirt is a dark color, the design will be more visible on the back of the shirt. Finally, consider the type of shirt you are printing on. If you are printing on a tank top, the design will be more visible on the back of the shirt. If you are printing on a t-shirt, the design will be more visible on the front of the shirt.