pro hessipng2ps,dir,multi=multi,file=file
if n_elements(multi) eq 2 then xy=multi else xy=[2,3]
if n_elements(file) eq 0 then nfile='idl.ps' else nfile=file(0)
zz=xy(0)*xy(1)
if n_elements(dir) eq 0 then dir=''
x=findfile(dir+'hsi_*.png')
if x(0) eq '' then return
set1ps,nfile,col=0,ys=24
n=n_elements(x)
for i=0,n-1 do begin
 if i mod zz eq 0 then multiplot,xy,asp=1.33333,xmar=[1,1],ymar=[1,1]
 if query_image(x(i)) eq 1 then arr=read_image(x(i),rr,gg,bb)
 y=arr
 j=where(arr eq 0)
 if j(0) ge 0 then y(j)=255
 j=where(arr eq 255)
 if j(0) ge 0 then y(j)=0
 j=where(arr eq 1)
 if j(0) ge 0 then y(j)=0 
 tvlct,rr,gg,bb 
 fitstvscl,y,/tv,/asp,/noint,/notick,tickl=1e-5,psgrid=640 
 multiplot
end
multiplot,/def
set_ps,0
end