set output 'four_cold_histograms.ps' 
set term postscript color 'Helvetica' 18  
set grid 
set key top right 
set xlabel 'Counts in a pixel' 
set ylabel 'Number of pixels ' 
set title 'Histograms of cold dark frames, Sep 24, 2003 '
plot [50:300][] 'dark1cold-001d.his' index 0 using 1:2 lc 1 pt 1 ps 1 lw 4    t '1 sec'  ,  'dark10cold-001d.his' index 0 using 1:2 lc 3 pt 1 ps 1 lw 4 t '10 sec'  ,  'dark20cold-001d.his' index 0 using 1:2 lc 4 pt 1 ps 1 lw 4 t '20 sec'  ,  'dark30cold-001d.his' index 0 using 1:2 lc -1 pt 1 ps 1 lw 4 t '30 sec'  
set output 
quit 
