You have probably already noticed: Lidl receipts are not white, but blue, even gray depending on the light. For what ?
You have probably already noticed: Lidl receipts are not white, but blue, even gray depending on the light. For what ? Lidl has been using greener paper for its receipts for several years now. This paper is chemical free. The receipt is also recyclable.
Today, cash receipts, parking tickets and train tickets are almost no longer printed with ink. Instead, what is called thermal paper is used. This contains a chemical color developer which, when heated, causes a reaction resulting in a dark discoloration. This means that in the printer, only the areas where letters or numbers should appear should be heated. There is also thermal paper without color developer: in this case, the black color is already contained in the paper and is covered with a white layer. When heated, the black color is revealed. The adjuvants used are considered non-problematic.
The blue paper used by Lidl works almost identically and can still be used in thermal printers. However, the mechanism of color formation is different. A layer of black pigments is applied to the paper, then a layer of polymers which gives the paper its blue appearance. Under the effect of heat, the polymer balls change structure and become transparent. The biggest advantage: receipts can now be recycled in our yellow bins. White thermal receipts, on the other hand, should be thrown away with household waste because they may contain substances such as bisphenol-B, which is toxic to certain aquatic and plant species according to Greenpeace.
In the past, receipts could even be coated with bisphenol-A, an even more toxic substance. This substance can have negative effects on health and damage the environment. France proposed the restriction of bisphenol A in receipts to protect pregnant cashiers and their unborn children, by filing a dossier with the European Chemicals Agency (ECHA) in January 2014.
A disadvantage of the blue color is that some find the receipt less readable. The contrast with the writing is weaker. However, new eco-friendly receipts do not yellow and remain legible for decades. But why is the receipt blue and not, for example, yellow? For technical reasons, the color cannot be changed and is therefore gray-blue: it is the famous polymers used that give this color and it is not possible for the moment to change the color.