Me again. While working on the previous report, I came across a strange bug with \letterspacefont: If the first control sequence is a single character, pdftex will abort with !pdfTeX error: pdftex (file ???+100ls): Font ???+100ls at 600 not found This does not happen with all fonts, e.g., in the following example, cmr10 would be fine, as would be changing \y to \xy: \font\x=cmr12 \letterspacefont\y\x 100 \y y \bye -- Robert