Braille language embossing is far different from that of the usual printing on surface because Braille is not a language. This is a tactile way of writing and reading texts, combining letters which are consist of six dots raised from the surface, having three dots placed parallel to each other. And therefore the challenges for Braille language embossing are numerous as well as vast.
Firstly, Braille on each package must be readable by the all blind and partially blind people. According to Braille legislation, all vital information should be easily accessible to everyone. For this, each Braille dot needs to be high enough to be easily read, and this is where the actual problem comes. Reason, it requires extremely high precision for which Braille each dot has to have appropriate height, neither too high that it will perforates the packaging, nor too low that reader will be unable to read them. Moreover, printer has to ensure that Braille dots are not malformed or missing.
Spacing is another critical issue for accuracy because the appropriateness of the embossing determines the precision of transmitting right information. Unfortunately, chances of misinformation are high in Braille language embossing. By mistake even if one dot is misplaced or malformed in a Braille cell, it can turn a 40mg dose into a 50mg dose, resulting into expensive lawsuits and product recall expenses. Such consequences make Braille quality control crucial and extremely necessary.
For quality control for Braille two types of technologies are used - optical and physical measurement. Optical technologies inspect quality of the embossed Braille by casting a light on the Braille dots and measuring the resultant shadow. The advantage of using optical system is the speed. It has a disadvantage as well, i.e. Braille dot shadows differ depending on the background color of package. Dark background makes it difficult to measure the shadow.
For this reason, physical method is considered more reliable wherein handheld caliper is used to measure the height of the dot, it provide very high précised data though it is more time consuming. Hence, for larger projects it is not very much preferred.