diff --git a/.gitattributes b/.gitattributes
index a764eb5..5c62bde 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -3,3 +3,7 @@
 _gereedschap/** linguist-vendored
 */build.py linguist-vendored
 *.py linguist-vendored
+
+# De dia-bestanden worden gegenereerd door maak_dias.py.
+**/project/slides/*.html linguist-generated
+**/project/*.html linguist-generated