diff --git a/src/AbstractCsv.php b/src/AbstractCsv.php
index 7209fed2..eef20803 100644
--- a/src/AbstractCsv.php
+++ b/src/AbstractCsv.php
@@ -468,7 +468,7 @@ public function prependStreamFilterOnWrite(string $filtername, mixed $params = n
     {
         $this->document instanceof Stream || throw UnavailableFeature::dueToUnsupportedStreamFilterApi(get_class($this->document));
 
-        $this->document->prependFilter($filtername, STREAM_FILTER_READ, $params);
+        $this->document->prependFilter($filtername, STREAM_FILTER_WRITE, $params);
         $this->stream_filters[$filtername] = true;
         $this->resetProperties();
         $this->input_bom = null;