ISO 24509 discusses the accessible design in ergonomics. ISO 24509 is an international standard on the estimation of the minimum legible font size to enhance safety and comfort people in their social activities.
ISO 24509 provides a method for estimating minimum legible font size for single characters, but not for words or sentences, in self-luminous or reflected mode, used in documents, products labels, signs, and displays for people at any age and in any viewing condition in which viewing distance, luminance, and contrast are varied.
ISO 24509 applies to design and evaluating legibility of single characters for people at any age who has no pathological disorders in their eyes, but not for people with visual impairments such as low vision. The application is specifically directed to, but not limited to, the cases of printed materials where fixed font size is used.
ISO 24509 on method for estimation of minimum legible font size is useful for:
Characters are widely used almost every time displays, documents, and other media for visual
information is involved. Accessibility to printed or displayed text is one of the critical issues in this age of mass information, especially for older people. However, methods for designing and evaluating the legibility of characters have not been well established yet.
ISO 24509 provides you with principles for accessible designs, application conditions, estimation of the minimum legible font size, correction by contrast effect, visual acuity data as a function of age and viewing distance.
The design conditions and methods provided by ISO 24509 assist in designing and evaluating the legibility of characters and help in improving the readability of people.
By adopting ISO 24509 the user can enhance the legibility of characters, user experience for brand development.
ISO 24509