When you click the Italic or Bold button in software, the result may be that the selected, text is reset in the corresponding italic or bold font, which is correct. It no such font is present, though, or if (in the case of Type 1 fonts) the software does not know which file it is, then all that happens is that the ordinary letterforms are either slanted to simulate italic or offset for bold. Not only are there effects unsightly, but they may not print. To be safe, choose the italic or bold version of the font from the menu, unless it is a TrueType font which has them in a single file.