diff --git a/lib/heathen/task.rb b/lib/heathen/task.rb
index 3ad2bca..f54b992 100644
--- a/lib/heathen/task.rb
+++ b/lib/heathen/task.rb
@@ -54,13 +54,13 @@ def task_key action, mime_type
 end
 
 Heathen::Task.register 'ocr', 'image/.*' do
-  convert_image to: :tiff, params: '-depth 8 -density 300 -background white +matte'
+  convert_image to: :tiff, params: '-depth 8 -density 300 -background white -alpha off'
   job.reset_content_file!
   tesseract format: 'pdf'
 end
 
 Heathen::Task.register 'ocr_text', 'image/.*' do
-  convert_image to: :tiff, params: '-depth 8 -density 300 -background white +matte'
+  convert_image to: :tiff, params: '-depth 8 -density 300 -background white -alpha off'
   job.reset_content_file!
   tesseract format: nil
 end