Selected Bibliography Architectural Graphics | Page 9

DRAWING LEADS Recommendations for Grades of Graphite lead 4H Graphite Leads Grades of graphite lead for drawing on paper surfaces rangefrom 9H(extremely hard) to 6B (extremely soft). Givenequal hand pressure, harder leads produce lighter and thinner lines, whereas softer leads produce denser, wider lines. - - - - - - - - • This dense grade of lead is best suited for accurately marking and layingout light construction lines. -------~ • The thin, light lines aredifficult to read and reproduce and should thereforenot be used for finish drawings. • When applied with too much pressure, the dense lead can engrave paper and board surfaces, leaving grooves that are difficult to remove. 2H - - - -- - -- C olored leads Nonphoto blueleads are used for guidelines that will not reproduce on photocopiers. Nonprint violet leads produce guidelines that will not reproduce on diazo machines; the lines, however, may print on photocopy machines. Test prints are therefore always advisable when using either non photo or non print leads. Plastic leads Specially formulated plastic polymer leads are availablefor drawing on drafting film. Grades of plastic lead range from EO, NO, or P (soft) to O E5, N5, or P5 (hard). The letters E, N, and Pare m anufacturer's designations; the num bers 0 t hrough 5 refer to degrees of ha rdness. • This medium-hard lead is also used for laying out drawings and is the densest grade of lead suitable for finish drawings. • 2H lines do not erase easily if drawn with a heavy hand. Fand H - - - - - - - - • These are general-purpose grades of lead suitable for layouts, finishdrawings, and handlett ering. HB • This relatively soft grade of lead is capable of dense linework and handlettering. - - - - - - - - • HB lines erase and print well but tend to smear easily. • Experience and good technique are required to control the quality of H linework. B - - - - -- - - B - - - - - - - - • This soft gradeof lead is used for very dense linework and handlettering. The texture and density of adrawing surface affect how hard or soft a pencil lead feels. The more tooth or roughness asurface has, the harder the lead you should use; the more dense a surface is, the softer alead feels. DRAWING TOOLS & MATERIALS I3