Many thanks for your answer.<br><br><div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">&gt;&gt; If I include some transparent stuff on a light background (i.e. a<br>
 &gt;&gt; metapost figure on a light gray screen), there&#39;s a visible rectangle around it (on<br> &gt;&gt; the screen). <br></blockquote><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Yes, it&#39;s unfortunately normal at least in Acrobat 7 and 8, also in<br> Apple&#39;s PDF viewer (in Preview, Mail etc.).<br> In my experience esp. transparent (or flattened) elements show a fine<br> white border - but if you zoom in, it stays the same fine line or<br>
 sometimes disappeares. And it never shows in print.<br> </blockquote></div><br><br>However, what I meant was slightly different: not a tiny white line around but a solid (full) rectangle with light gray background. You can see it here: <a href="http://www.econ.muni.cz/~qasar/tmp/inst-slide02.pdf">http://www.econ.muni.cz/~qasar/tmp/inst-slide02.pdf</a>, page 3 (the ugly background in the figure on the page 2 is my fault).<br>
<br>I guess the light gray background might be another bug in the AdobeReader, since it&#39;s not visible in xpdf. However, I thought so with the previous bug (it was visible in the AdobeReader, but not in the xpdf too), and it was actually a bug in the pdfTeX.<br>
<br>Have you any idea what&#39;s wrong? (Well, this is much less annoying than the previous problem.)<br><br>Many thanks and greeting from rainy Brno.<br>Michal<br><br>