The addition of minimal letter-spacing can often increase the legibility and readability. Legibility and readability tend to support aesthetic aspects of a product. Studies have been conducted on the readability and legibility of all caps text. Other changes include improved legibility, heavier punctuation marks, and increased spacing in the numbers. Reducing the stroke width below a certain point impairs legibility. Its tight, display-oriented spacing may also pose problems for legibility. Entities help to improve legibility of an XML text. These visual corrections were made for legibility. English scribes adapted the Carolingian script, giving it proportion and legibility. Further, issues of legibility and authenticity have been raised among researchers. Not all writing benefits from optimizing for legibility. Leading can be used to enhance the legibility of a page or block of text. A subtle change in proportion impacts weight, perception, measure, and legibility. Anti-reflective coatings are generally applied on sapphire crystals to enhance the legibility of the watch. Two traits of good labels are legibility and easy feature association.