[pdftex] Re: expansion & protruding

[A.V.Kuznetsov]

The Thanh Han writes:
 > protruding (or margin kerning) doesn't not increase file size -- it doesn't
 > use any extra fonts but simply makes adjustment of characters placement at
 > the margins. I call a font with slightly changed width as expanded font.
 >
Dear Thanh,
What is a difference between slightly and ordinarily expanded font?
Why only one of them is embedded? Can one conclude that pdftex is
able to use expanded font without its embedding but this ability is
used only for font protruding?
Sincerely,
A.V.Kuznetsov