Much information is needed on a packaging. Demands can come from laws, cosumers, needs for instructing users, demands from the supply-chain etc. such information can be photos, drawings, text, barcodes etc. and of cause such information shall readable and be able to be used. And for this reason a package can be imitated in order to contain all information. Such a limitation shall be documented.
Information as barcodes is defined through international standards for readability. But it is more difficult to define the human perception of text and illustrations. In the end it is a definition of the sizes of the letters and pictures before human can read and understand. Older people need bigger sizes than young. But disables can need very big sizes. So a target group can in the end define packaging size.