Pencils are graded using the ‘Graphite Scale’ which measures the softness/hardness of the lead.

鉛筆用石墨含量來給鉛芯的硬度或者黑度分級。

A pencil lead is made from graphite mixed with clay. Graphite is a naturally soft substance and clay is mixed with it to make it harder. This means a lead with a high graphite content is known as a soft lead and pencils with a soft lead will make a dark mark when used.

鉛芯是由石墨和粘土混合制成的。石墨是一種天然的軟物質(zhì)，人們把它和粘土混合在一起使它變硬。這意味著石墨含量高的鉛被稱為軟鉛，軟鉛的鉛筆在使用時會留下黑色的痕跡。

Conversely, a lead with less graphite and a higher clay content is known as a hard lead and will make a lighter mark.

相反，石墨少而黏土含量高的鉛被稱為硬鉛，它留下的痕跡較淺。

Soft leads are graded using the letter ‘B’ to designate how ‘black’ the mark they make is. Numbers are then used to indicate the degree of softness - the higher the number the softer the lead and the blacker the mark. For example, a 2B lead is softer than a B lead and will produce a blacker mark. A 4B lead is softer than a 2B etc.

軟鉛芯用字母B來表示它們黑的程度。然后，數(shù)字被用來表示柔軟程度——數(shù)字越高，鉛越軟，所以畫出來越黑。例如，2B鉛比B鉛軟，會產(chǎn)生更黑的痕跡。4B比2B等要軟。

Hard leads are graded in the same way, but use an ‘H’ to show how ‘hard’ they are. A 2H is harder than an H and a 6H is really really hard.

硬鉛芯以同樣的方式評級，但用H來表示它們有多硬。2H比H硬，6H非常非常硬。

HB (hard black) leads are considered to be the happy medium on the graphite scale. There are no specific industry standards that set down how black HB leads should be, so an HB pencil made by one manufacturer will not necessarily leave the same mark as an HB pencil from a different manufacturer.

硬黑鉛被認為是石墨刻度上的理想中值。并沒有具體的行業(yè)標準來規(guī)定HB鉛筆芯應(yīng)該有多黑，所以一個制造商生產(chǎn)的HB鉛筆并不一定會和另一個制造商生產(chǎn)的HB鉛筆留下相同的痕跡。