The letter spacing option allows to justify the short lines that couldn't reach the right margin otherwise.

The justification setting regards only the justified text lines that are too short even when the maximum allowed space has been added between words. All other lines of text are not affected with this setting. The lines of text that are aligned left, right or centred, are never affected with this setting.

•If the letter spacing option is on, the additional white space is added proportionally between all the letters in the justified line that was too short, untill the line extends to fit the column. This can cause the text line to look like:

a   s h o r t     l i n e   t h a t   c a n n o t    b e    j u s t i f i e d

•If the letter spacing is off, the additional white space is added proportionally between all the words in the justified line that was too short, untill the line extends to fit the column.

This can cause the text line to look like (the sample is exagerated by purpose):

a     short      line        that            cannot   be     justified