Thanks for the answer.
First, it's not a transparency problem, when i edit the text width Acrobat, in properties the color is RGB(146,146,146).
Second, here is my code so you can see exactly what i'm doing :
Code:
this.stats = PdfReader.Open("C:/foo/stats.pdf", PdfDocumentOpenMode.Modify);
this.graphics = XGraphics.FromPdfPage(this.stats.Pages[0]);
this.graphics.DrawString(
"04/08/2010",
new XFont("Arial", 9),
new XSolidBrush(XColor.FromArgb(1, 1, 1)),
new XRect(this.x, page.Height - this.y, this.width, this.height),
XStringFormats.Default);
this.stats.Save("C:/foo/result.pdf");
Finally, using XColor.FromArgb(1, 1, 1) worked like a charm (though it's not exactly black).
Would you like me to PM you the files stats.pdf and result.pdf to see what's exactly going on in PDFSharp ?