And never remove watermarks to misrepresent ownership—that’s where engineering becomes forgery. This piece was assembled from real GitHub source analysis and PDF internals documentation. The code examples run on Python 3.8+ with PyMuPDF installed ( pip install PyMuPDF ).
for page_num in range(len(doc)): page = doc[page_num] # Method 1: Draw white over watermark (crude but works) page.draw_rect(common_rect, color=(1,1,1), fill=(1,1,1), width=0) # Method 2: Remove text objects (more aggressive) page.clean_contents() doc.save(output_pdf) doc.close()
# Most watermarks are at same coordinates across pages common_rect = fitz.Rect() if watermarks: common_rect = watermarks[0] # simplify: take first pdf remove watermark github
# Step 1: Generate a mask where watermark exists (manual ROI) convert input.pdf[0] -threshold 50% mask.png for i in $(seq 0 $(pdfinfo input.pdf | grep Pages | awk 'print $2')); do convert input.pdf[$i] mask.png -compose dst_out -composite page_$i.pdf done Step 3: Rebuild PDF and OCR pdfunite page_*.pdf no_watermark.pdf ocrmypdf no_watermark.pdf final_clean.pdf --deskew --clean
This assumes watermark is in same bounding box. Real watermarks rotate, semi-transparent, or appear per-page differently. 4. Advanced: Remove by Redaction (Forensic Clean) import fitz def redact_watermark(input_pdf, output_pdf, search_text="Confidential"): doc = fitz.open(input_pdf) for page in doc: text_instances = page.search_for(search_text) for inst in text_instances: page.add_redact_annot(inst, fill=(1,1,1)) page.apply_redactions() doc.save(output_pdf) for page_num in range(len(doc)): page = doc[page_num] #
This physically removes the text—even from copied text layer. Image watermarks (scan of a stamp, logo) require a different approach:
From a technical perspective, a watermark is just another layer of PDF content—text, vector art, or image—drawn over or under the main content. PDF’s stacking model makes removal possible via content filtering. | Tool | Stars | Method | Best for | |------|-------|--------|----------| | pdfrw + custom script | ~500 | Filter page contents by type | Text watermarks | | PyPDF2/PyMuPDF (fitz) | 6k+ | Remove annotations/overlay objects | Stamped watermarks | | pdfCropMargins | ~300 | Crop then scale | Edge watermarks | | OCRmyPDF + masking | 4k+ | OCR + regenerate | Image-based watermarks | | Stirling-PDF | 20k+ | GUI + CLI with “Remove Watermark” | Non-technical users | Advanced: Remove by Redaction (Forensic Clean) import fitz
# Detect watermark region (first page, look for repeated gray text) first_page = doc[0] watermarks = [] for block in first_page.get_text("dict")["blocks"]: for line in block.get("lines", []): for span in line.get("spans", []): if span["color"] < 0.5: # dark gray/black threshold bbox = fitz.Rect(span["bbox"]) watermarks.append(bbox)