Bar codes are present in the lives of all of us, and we end up wondering how they work every time we go to the supermarket. How do those black lines identify a product? Do they only work in that supermarket or anywhere in the world? Let’s find out in the next few lines.
Black and white
Explaining briefly, barcodes work binary. The white part represents “1” while the black part represents “0”, and blocks of bars form numbers.
As we can see in the image below, there are delimited positions for each bar, and they are very small. This means that thick bars represent “0” consecutive, while larger white areas represent “1” consecutive.
How can the reader differentiate between one and the other? When it passes through a white area it receives the reflected light (“1”), which does not happen with the black regions (the “0” s). Basically, this is what the reader does: read the entire code, convert to decimal numbers and find the corresponding product in the database.
But wait: are the codes valid for everyone or just for a specific supermarket?
GS1 and non-standard codes
The GS1 is an international organization that controls the pattern of bar codes. Headquartered in Brussels, Belgium, it registers each of the products used worldwide. That is, the codes are universal, even if they are divided by countries. Brazil, for example, has codes beginning with “789”.
That is, these codes are linked directly to a certain product, regardless of where we buy – except when they are generated on demand.
Yes! Some of them are generated freestyle, such as when we buy products in bulk. In these cases, the code is valid only to make it easier to read the box at the time of payment, not being a bar code of “403 grams of cheese plate from the supermarket X”.