Carry any non-periodic editions in the form of the stitched sheets of printing material more than 48 pages to books, as a rule, in a cover or a cover (GOST 16 447 — 70). Sheets in To. can be from paper, a cardboard, fabric, the clear film, a metal foil and other materials perceiving prints. Gigabyte. requirements to To. are directed to the prevention of the general and visual exhaustion during the reading. Degree of exhaustion during the reading To. depends on its printing execution, and also illumination during the reading. Special attention is paid to registration To. for children whose visual device is in a stage of formation. Visibility of the text To. decides by quality of paper (color, smoothness, translucence) and the press (its contrast on a background, a saturation and a tonality of paint). Legibility of the text is defined by character of printed characters (font sizes, a font), way of their arrangement on the page — set (length of a line, size of fields).
Letters are perceived on a tracing of the main strokes, mainly vertical. The more small strokes and the are closer one to another they are located, the eyes strain more during the reading. Height of the main strokes in the educational book for elementary grades shall be 2,0 — 2,8 mm, thickness of 0,3 mm, distance between them — not less than 0,5 mm; thickness of binding (additional) strokes is 0,15 mm, for abc-books and books for kids height of a font 4,5 — 8 mm, for To. help height of a font can be less than 1,5 mm.
Certain requirements are imposed also to registration K. Dlina of a line in books for adults and the advanced children's age — 98 mm, in books for younger children's age lengthening of a line to 130 mm at a large print is recommended, interlower case distance — 3 mm, distance between words not less than 2 mm, distance between separate letters of 0,5 mm. In the sum these requirements determine density of a font, i.e. the number of letters on 1 cm2, a cut shall not exceed 15, and for the nursery To. — 10. Fields K are of great importance. Wide fields facilitate reading since accurately limit the text from surrounding space.
Width of fields is established depending on a format and appointment To.
At registration art and educational To. for younger children's age use of two-columned set is not allowed, at Krom the number of lines and frequency of the movement of eyes during the reading increases that leads to bystry exhaustion. Length of a line and width of fields define a format K.
At a gigabyte. control To. its weight, a format, a way of a broshyurovka, a cover, color, a surface, brightness and density of paper, quality of the press, font and illustrations is estimated. Strokes, length of a line and letters are measured by a ruler with divisions of 0,1 mm, and density of a font — quantity of the letters seen through an opening in 1 cm2. For measurement of elements of letters under a magnifying glass it is recommended to take a letter «H».
To read To. follows only at sufficient lighting (see) and to have it at distance of 35 — 40 cm from eyes.
To. can be the transmitter of an infection. On the textbooks which were in the use, on library To. pathogenic microorganisms find. The bottom right corner of the page is especially contaminated, touch Krom during the browsing. Survival of bacteria on pages of books is rather big. To., to-rymi infectious patients used, disinfection shall be exposed. Enough efficiently disinfection processing is To. vapors of formalin, and also radiation by short-wave Uv-radiation.
Bibliography: Bolshakov M. V., Buckwheat x about G. V. and Sh and c of and A. G l. Book font, M., 1964; Hygiene of training of children of school age, under the editorship of G. N. Ser-dyukovskaya, M., 1969; At shch e in and T. M., D olzhenok of V. V. and Neshumo-v and N. F. O the standard on ergonomic requirements to font designations, the Industrial art, No. 11, page 12, 1976; Popova N. M. Hygienic problems of the school textbook at the present stage, the Gigabyte. and dignity., No. 10, page 32, 1976; Sequential development of reading abilities, ed. by H. M. Robinson, Chicago, 1960.
Yu. D. Zhilov.