diff --git a/scripts/contrast-test.sh b/scripts/contrast-test.sh
index a3a9aed8..9d17a04d 100644
--- a/scripts/contrast-test.sh
+++ b/scripts/contrast-test.sh
@@ -2,9 +2,9 @@
 
 CMDPATH="/usr/local/bin"
 
-WS="./tmp"		# our workspace
+WS="${HOME}/TMP"		# our workspace
 
-GRABOPT=" -d /dev/video0 -vu -n 240 -p 0.04 "
+GRABOPT=" -d /dev/video0 -v -n 240 -p 0.04 "
 
 GRAB=${WS}/"quux.fimg"
 COS01=${WS}/"cos01.fimg"
@@ -15,9 +15,9 @@ POW2="${WS}/pow2.fimg"
 # --------- conversion fimg -> pnm
 f2p ()
 {
-dst=$(basename $1 .fimg).pnm
+dst=EC_$(basename $1 .fimg).pnm
 echo == converting $1 to $dst
-${CMDPATH}/fimg2pnm  $1 $dst
+${CMDPATH}/fimg2pnm  $1 ${WS}/$dst
 }
 
 # --------- capturer une image
@@ -43,4 +43,4 @@ f2p $COS010
 # ----------- présentation finale
 #
 echo == Making gif89a
-convert -delay 40 *.pnm foo.gif
+convert -delay 40 ${WS}/EC_*.pnm foo.gif