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src/pretix/base/invoice.py

@@ -389,6 +389,10 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
                 logger.exception("Can not resize image")
                 pass
             try:
+                # Valid ZUGFeRD invoices must be compliant with PDF/A-3. pretix-zugferd ensures this by passing them
+                # through ghost script. Unfortunately, if the logo contains transparency, this will still fail.
+                # I was unable to figure out a way to fix this in GhostScript, so the easy fix is to remove the
+                # transparency, as our invoices always have a white background anyways.
                 ir.remove_transparency()
             except:
                 logger.exception("Can not remove transparency from logo")