Method of producing planographic printing plate support

A method of producing a planographic printing plate support, comprising the following steps:

• continuously casting molten aluminum into an aluminum thin plate in a forward direction;
• cold rolling said plate so that said plate is of a predetermined thickness;
• heating said plate;
• flattening said plate so that said plate has a predetermined flatness;
• and
• roughening a surface of said plate, wherein the Fe content is selected to be in a range of from 0.4 weight % to 0.2 weight %, the Si content is selected to be in a range of from 0.20 weight % to 0.05 weight %, the Cu content is selected to be in a range of not larger than 0.02 weight %, and the Al purity is selected to be not smaller than 99.5 weight % and wherein the grain size of the aluminum plate after the continuous casting is in a range of from 2 .mu.m to 500 .mu.m in a section perpendicular to the forward direction and the grain size of the aluminum plate after final cold rolling or annealing is in a range of from 2 .mu.m to 100 .mu.m in said section.

A method of producing a planographic printing plate support, comprising the following steps:

• continuously casting molten aluminum;
• hot rolling said molten aluminum into an aluminum plate having a thickness ranging from 4 mm to 30 mm;
• cold rolling said aluminum plate while the temperature of said aluminum plate is in the range of 100.degree. C. to 250.degree. C. so that said plate is of a predetermined thickness;
• heating said plate;
• flattening said plate so that said plate has a predetermined flatness;
• and
• roughening a surface of said plate.