Cardboard tags, hang tags or hang tags: Specific volume, weight and thickness of paper
Hanging tags with lettering. When we talk to our customers about the paper to be used to manufacture their cardboard labels, hang tags or hang tags, we very often hear: «I want a thick paper» or «I want a paper with body», trying to convey an idea about the type of printed medium they want for their hang tags.
We use the term «grammage» as an indication of a certain type of paper, but to interpret it correctly we must distinguish between three basic concepts that are very important when selecting the type of paper: grammage, thickness and volume, three properties that are related to each other.
- When we talk about grammage on cardboard labels, we are referring to the weight of the paper (in grams per square metre), which is often confused with thickness. A paper weight of 400 g/m² indicates exactly that, that if we cut a sheet of 1 square metre, its weight would be 400 grams.
- Thickness is measured with a micrometer, and indicates the distance between the two surfaces of the paper in microns -µm- (thousandths of a millimetre). This concept affects the stability, feel and especially the thickness of the hang tags.
- The specific volume defines the ratio between thickness and grammage. The more volume a paper has, the thicker and lighter it is. However, a paper with a low volume will be more compact, thinner and heavier. This is due to the proportion of air and fillers it contains between its fibres, with low-volume paper being softer and vice versa.
The relationship to calculate these three values, and why they are related, is as follows:
Grammage = Thickness / Volume
For example, we can have two types of paper, both 130 g/m², but one with a thickness of 234 µm and the other with 143. The volume would be calculated by dividing both values and obtaining as a result that one will have a volume of 1.8 (light and thick) and the other of 1.1 (compact and thin). Approximately from 1.3 cm³/g we can start to consider that a paper has volume (carteo).
Conclusion: The specific volume, or «bulk» in English, is a very important factor in production and influences the perception of the final result of the hangtag. If we want to give the impression of a very thick cardboard label, a high bulk paper should be used.