diff --git a/werk24/models/ask.py b/werk24/models/ask.py
index ef759c0..e8ea987 100644
--- a/werk24/models/ask.py
+++ b/werk24/models/ask.py
@@ -274,6 +274,8 @@ class W24AskSheetAnonymization(W24AskThumbnail):
             to fill the pixels that are to be redacted. Currently
             only grayscale is supported.
 
+        output_format (W24FileFormatThumbnail): Output format in
+            which to generate the anonymized sheet. 
     """
 
     ask_type: W24AskType = W24AskType.SHEET_ANONYMIZATION
@@ -288,6 +290,12 @@ class W24AskSheetAnonymization(W24AskThumbnail):
 
     fill_color: Tuple[int, int, int] = (255, 255, 255)
 
+    output_format: W24FileFormatThumbnail = Field(
+        description="Output format in which to generate the anonymized sheet.",
+        examples=[W24FileFormatThumbnail.PNG, W24FileFormatThumbnail.PDF],
+        default=W24FileFormatThumbnail.PNG,
+    )
+
 
 class W24AskPartFamilyCharacterization(W24Ask):
     """Triggers a post-processor that turns the raw data into a
diff --git a/werk24/models/file_format.py b/werk24/models/file_format.py
index 9627083..88f91ca 100644
--- a/werk24/models/file_format.py
+++ b/werk24/models/file_format.py
@@ -19,7 +19,7 @@ class W24FileFormatThumbnail(str, Enum):
 
     This can either be a JPEG or a PDF.
     """
-
+    PNG = "PNG"
     JPEG = "JPEG"
     PDF = "PDF"