seeing red (in postscript output)

["Richard G. French" <rfrench(at)wellesley.edu>]

I'm posting this for my brother - trying to maintain inter-family
harmony here. it's an IDL routine that creates
a PostScript file containing a TV image and an overplotted
set of axes. The problem is that the output has an extra column
of pixels - all red, in this case - that extend outside of the plot
boundary. I know that there are other ways to do what is 
being done here, but my immediate question is:

Is there an easy way to modify THIS code so that the
extra column of pixels is not present?

Thanks for any tips! 
Dick French

;demonstrate problem with tv

;define image array
pixels = 23L
lines = 7L
demo_image = bindgen(pixels,lines)


;set up postscript page size and offsets
pgxsz = 6.0
pgysz = 9.0
pgxoff = 1.0
pgyoff = 1.0

;set image x size, compute y size via aspect ratio
ximgsz = 5.0
aspect = float(pixels)/float(lines)

;get bounds of image in inches
yimgsz = ximgsz/aspect
xposl = 0.0
xposr = xposl+ximgsz
yposb = 0.0
ypost = yposb+yimgsz

;compute normalized coordinates of image bounds and use these for plot
overlay
xposln = xposl/pgxsz
xposrn = xposr/pgxsz
yposbn = yposb/pgysz
ypostn = ypost/pgysz

;define coordinate system of plot
;using 'origin' as lower left corner
utme_rng = [575000.0,603008.0]/1000.0
utmn_rng = [3929996.0,3938000.0]/1000.0 ;coords in km

;compute the physical pixel size
pixdim = (utme_rng[1]-utme_rng[0])/float(pixels)

;set up postscript device
pfil = 'demoproblem.ps'
set_plot,'ps'
device,/portrait,file=pfil,/inches,xsize=pgxsz,ysize=pgysz,xoffset=xoff,yoffset=yoff,/COLOR

;load a color table
loadct,13 ;rainbow colors

;check image dimensions before tv
szimagebefore = size(demo_image)

;display the image
tv,demo_image,xposl,yposb,/inches,xsize=ximgsz,ysize=yimgsz

;check image dimensions after tv
szimageafter = size(demo_image)

;print the image sizes
; they will be the same!
print,'szimagebefore ',szimagebefore
print,'szimageafter ',szimageafter

;plot the coordinate axes
plot,utme_rng,utmn_rng,/nodata,title='Demo Image Display Problem',$
 xtitle='UTME14 (km)',ytitle='UTMN14 (km)',/noerase,$
 xstyle=1,ystyle=1,position=[xposln,yposbn,xposrn,ypostn],/normal

;number the columns starting with zero
;
lblposy = utmn_rng[0]+((lines-2)+0.5)*pixdim

for pct = 0,pixels-1 do begin
 lblposx = utme_rng[0]+(pct+0.0)*pixdim
 colnumstr = string(pct,format='(i2)')
 xyouts,lblposx,lblposy,colnumstr,color=1
endfor

;close the ps device
device,/close

end