\startenvironment paper

% Proefschrift formaat is 17x24cm
% We doen aan beide zijden 5mm afloop, zodat we plaatjes vol kunnen printen
\definepapersize[proefschrift+rand][width=180mm, height=250mm]
\definepapersize[proefschrift][width=170mm, height=240mm]

\setuppapersize[proefschrift][proefschrift+rand]
\setuplayout[location={middle,middle}]
\setuplayout
  [width=130mm,
   height=215mm,
   backspace=20mm,
   topspace=15mm,
   header=10mm, % nodig?
   footer=10mm]

% Snijranden
\setuplayout[marking=on]

% Assymetrisch
\setuppagenumbering[state=start, style=normal, location={header, right}, alternative=doublesided]

\startmode[draft]
\setuppapersize[A5]
\setuplayout
  [width=130mm,
   height=205mm,
   backspace=12mm,
   topspace=3mm,
   header=5mm, % nodig?
   footer=5mm]
\stopmode

\stopenvironment