set output './transfer_b.ps' 
set term postscript color 'Helvectica,18'  
set style line 1 lt rgb 'red' lw 3  
set style line 2 lt rgb 'sea-green' lw 3  
set style line 3 lt rgb 'blue' lw 3  
set style line 4 lt rgb 'cyan' lw 3  
set style line 5 lt rgb 'violet' lw 3  
set style line 6 lt rgb 'orange' lw 3  
set style line 7 lt rgb 'black' lw 3  
set grid 
set key center right 
set ylabel 'Intensity / (Initial intensity)' 
set xlabel 'Optical depth travelled ' 
plot [0:5][0:2] 1*(exp(-x)) + 1.8*(1 - exp(-x))     with lines  ls 2  t 'S = 1.8 I_0'  ,              1*(exp(-x)) + 0.3*(1 - exp(-x))     with lines  ls 3  t 'S = 0.3 I_0'  
set output 
quit 
