This article considers the implications of different types of label material. The labels are assumed to be on a roll, with a cardboard core in the centre.
Paper labels
These are the cheapest labels and can be made reasonably splash-resistant by using a coating. They stretch, which makes them more accommodating of blemishes in the containers to which they are applied. If the label is specified to wrap around the container with a small gap between the ends, the label ends may overlap if too much tension is applied.
Transparent labels
These are made of plastic and show the content of the container. If the bottle has blemishes, air will be trapped in the vicinity of the blemish, and it will be difficult, if not impossible to remove it. You will need a special sensor or a black line on the backing sheet, as they cannot be directly detected by an optical sensor. Transparent labels may be used without modification on a manual applicator, as a pointer can be set to any visible mark on the label, to know when to stop applying it.
Opaque plastic labels
These labels are plastic, but they can be detected by a standard sensor as they are not transparent. They include labels that are metallized. They often do not have much stretch, and like transparent labels, a good quality bottle is needed to obtain the best results. They are often used because they are impervious to water, and they can provide a high-quality look to the product.