diff --git a/app/models/dmsf_file_revision.rb b/app/models/dmsf_file_revision.rb
index d10d3b40..570c8835 100644
--- a/app/models/dmsf_file_revision.rb
+++ b/app/models/dmsf_file_revision.rb
@@ -391,7 +391,7 @@ def workflow_tooltip
   end
 
   def protocol
-    @protocol ||= PROTOCOLS[mime_type]
+    @protocol ||= PROTOCOLS[mime_type.downcase]
     @protocol
   end