Automated (scripted) editing of PDF metadata, security settings, watermarks, etc.?

Yes, it's possible, using various tools (I've developed tools in Java that do it, for example), but if you want to use Python that's unrelated to Acrobat so not really the subject of this forum.

After posting my question above, I also presented it to ChatGPT-4.  Here is its unedited response, which I haven't yet verified for accuracy (always necessary with ChatGPT!) :

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Yes, there are several ways to automate the process of adding metadata, watermarks, and security settings to PDFs using Python. The Python ecosystem offers libraries such as PyPDF2, ReportLab, and PyMuPDF that can be used to manipulate PDF files. Here's a brief overview of how you could use these tools to achieve your goals:

1. Adding Metadata:
- You can use PyPDF2 to add or modify metadata in a PDF file. Metadata can include information about the authorized user or any other details you wish to embed.

2. Applying Watermarks:
- ReportLab can be used to create a watermark as a separate PDF. You can then merge this watermark PDF with each page of your textbook PDF using PyPDF2.

3. Applying Security Settings:
- PyPDF2 allows you to encrypt PDF files and set permissions to restrict actions like editing, printing, or copying text.

4. Automation Script:
- You can write a Python script that takes the user's details, generates a watermark, adds metadata, and applies security settings to each PDF. This script can process multiple files in a batch, significantly reducing the manual effort.

Here's a basic outline of how such a script might look:

```python
import PyPDF2
from reportlab.pdfgen import canvas
from PyPDF2.pdf import PageObject
from io import BytesIO

def create_watermark(content):
# Create a watermark PDF
packet = BytesIO()
can = canvas.Canvas(packet)
can.drawString(10, 10, content)
can.save()

# Move to the beginning of the StringIO buffer
packet.seek(0)
new_pdf = PyPDF2.PdfFileReader(packet)
return new_pdf.getPage(0)

def add_watermark(input_pdf, watermark, output_pdf, user_metadata):
# Read the input PDF
pdf_reader = PyPDF2.PdfFileReader(open(input_pdf, "rb"))
pdf_writer = PyPDF2.PdfFileWriter()

# Add metadata
pdf_writer.addMetadata(user_metadata)

# Add watermark to each page
for i in range(pdf_reader.getNumPages()):
page = pdf_reader.getPage(i)
page.mergePage(watermark)
pdf_writer.addPage(page)

# Apply encryption
pdf_writer.encrypt(user_password="user_password", owner_password="owner_password", use_128bit=True)

# Write the output PDF
with open(output_pdf, "wb") as out:
pdf_writer.write(out)

# Example usage
watermark = create_watermark("Authorized User: John Doe")
user_metadata = {'/Author': 'John Doe'}
add_watermark("input.pdf", watermark, "output.pdf", user_metadata)
```

Note:
- This script is a basic example. You'll need to adapt it to your specific requirements.
- Ensure that the use of encryption and watermarking complies with the legal standards and privacy policies relevant to your region and industry.
- Test the script thoroughly to ensure that it meets your quality standards before applying it to your commercial textbooks.