diff --git a/ext/custom-addons/dp_custom/models/stock.py b/ext/custom-addons/dp_custom/models/stock.py
index 9120acfe..dbbf7fb7 100644
--- a/ext/custom-addons/dp_custom/models/stock.py
+++ b/ext/custom-addons/dp_custom/models/stock.py
@@ -77,7 +77,10 @@ class StockPicking(models.Model):
 
             if msg != '':
 #                signature2attach = []
-                ps = prime_signature.encode('ascii')
+                if isinstance(prime_signature,bytes):
+                    ps = prime_signature
+                else:
+                    ps = prime_signature.encode('ascii')
                 signature2attach = {
                     "filename": r'Signature.jpg',
                     "binary" : ps