what is the optimal line length for ideal legibility
Line length Traditional line length research, limited to print based text, resulted in a variety of results but generally for printed text it is widely accepted that line length fall between 45-75 characters per line (cpl), though the ideal is 66 cpl (including letters and spaces).[1] For conventional books line lengths tend to be 30 times the size of the type, but between 20 and 40 times is considered acceptable (i.e. 30 x 10pt font = 300 pt line).[1] Early studies considered line lengths between 59–97 mm (about 57 cpl) is optimum for 10 point font.[2] For printed works with multiple columns 40-50 cpl is often better.[1] For justified, English language text the minimum number of characters per line is 40 characters; anything less than 38-40 characters often results in splotches of white spaces (or rivers) or too many hyphenations in the block of text.[1] Longer lines (between 85-90 cpl) may be acceptable for discontinuous text such as in bibliographies or footnotes, but for continuous text lines with more than 80 characters may be too long. Short text, such as ragged marginal notes, may be as little as 12-15 characters per line.[1] Studies have shown that short lines are often preferred over long lines by study participants, likely because they feel more at ease with format, which contradicts research suggesting longer lines are best for quick reading.[3]
Long jump At the elite level, competitors run down a runway (usually coated with the same rubberized surface as running tracks, crumb rubber also vulcanized rubber—known generally as an all-weather track) and jump as far as they can from a wooden board 20 cm or 8 inches wide that is built flush with the runway into a pit filled with finely ground gravel or sand. If the competitor starts the leap with any part of the foot past the foul line, the jump is declared a foul and no distance is recorded. A layer of plasticine is placed immediately after the board to detect this occurrence. An official (similar to a referee) will also watch the jump and make the determination. The competitor can initiate the jump from any point behind the foul line; however, the distance measured will always be perpendicular to the foul line to the nearest break in the sand caused by any part of the body or uniform. Therefore, it is in the best interest of the competitor to get as close to the foul line as possible. Competitors are allowed to place two marks along the side of the runway in order to assist them to jump accurately. At a lesser meet and facilities, the plasticine will likely not exist, the runway might be a different surface or jumpers may initiate their jump from a painted or taped mark on the runway. At a smaller meet, the number of attempts might also be limited to four or three.