This is a term that most frequently applies to visually impaired and blind users of print material. Its partner term is “Alternate Format.”
Standard print is usually published in either 10- or 12-point fonts (6 or 7 characters per linear inch). Many sighted people wear eyeglasses or contact lenses that correct their vision to 20/20 which is adequate vision to read such print. However, to be classed as “legally blind”, the technical term for the partner term “visually impaired”, one would only have 20/200 vision in the best eye with the best correction possible. Ten- or 12-point type is completely inaccessible to those individuals who have this very limited amount of vision or to those with even worse or no vision.
The Americans with Disabilities Act (ADA) sets 14 point (5 characters per inch) as the “minimum” font size. However, many other resources emphasize that this font size is only a minimum and a legally blind individual may only be able to read the largest fonts starting at 18 point (4 characters per inch).
At some point (around 36 point), a print document will become nearly unusable because of the sheer volume of paper required to hold the very large print. Imagine a novel, letter or government report printed with just a very few large font words per page. Also, for someone with no vision, there obviously wouldn’t be any font size that will be accessible.
Braille, Audiotape, Oral Presentation and Electronic Format are the other most common accessible formats discussed in regulations. Each has its drawbacks and its useful purposes. Each has merited its own place in our glossary of terms.