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Anonymizing PowerPoint decks: names, logos and speaker notes
Anonymize a PPTX in your browser before an AI summarizes or translates it: slide text, tables and notes change, logos and images do not. Workflow and caveats.
Published 6 min read
Slide decks travel. A pitch, a board update, a customer case study or a training deck gets forwarded, reused and, increasingly, handed to an AI assistant for a summary, a translation or speaker notes. Decks are also full of identifying material: client names on every slide, a logo in the corner, a speaker note that says what the room should not hear. This guide explains what happens when you anonymize a PPTX with Unformation, what is deliberately not touched, and a short workflow to run before you send a deck to a model.
What is inside a PPTX
Like Word and Excel files, a .pptx is a zip archive of XML parts. For anonymization the interesting ones are:
- Slides. Every text box, title, bullet list and table cell on a slide is stored as text runs in the slide's XML.
- Notes slides. Speaker notes are separate parts linked to each slide. They are frequently more sensitive than the slide itself.
- Layouts and masters. Templates that supply the design; they can contain footer text such as a company name or "Confidential, prepared for Acme".
- Media. Images, logos, videos and audio, stored as binary files.
- Charts. Chart parts with their own XML, which usually embed a copy of the underlying data (category names, series names, values).
- Comments. Reviewer comments, with author names.
- Document properties. Author, company, title, last modified by.
Unformation processes the parts that carry document text: slides (including tables), the notes slides linked to them and any orphan notes parts, and the core document properties. The result is a valid .pptx with the same design plus a Markdown version of the deck for pasting into a chat, and the mapping table.
What is replaced and what is not
| Element | After anonymization |
|---|---|
| Titles, bullets, text boxes | replaced with consistent labels |
| Tables on slides | cell text replaced |
| Speaker notes | replaced |
| Document properties | scrubbed or replaced |
| Layout, fonts, colours, animations | unchanged |
| Logos and images | unchanged (pixels are not read or edited) |
| Text inside images or screenshots | not read |
| Charts | chart parts and their embedded data are not rewritten (see caveat) |
| Comments, slide masters | check the review list; remove manually if needed |
| Embedded Excel or Word objects | not opened; treat as separate files |
Two points deserve emphasis:
Logos. A logo is an image; the tool does not paint over it. If the deck must not reveal which company it is about, remove or swap the logo on the master slide before or after anonymization. The same applies to product photos and screenshots that show names.
Charts' embedded data. A native PowerPoint chart carries its own data (often a small embedded workbook and a cached copy inside the chart XML). Category labels like "Acme", "Beta Ltd" and series names like "J. Doe pipeline" live there, not in the slide text, so they are not replaced. Before sharing a deck whose charts name clients, either paste the chart as an image (which hides the data, though the labels are still visible pixels), rebuild it with labelled categories, or delete the chart and let the assistant work with the numbers you paste.
Consistent labels across the whole deck
The value of anonymizing a deck as one document rather than slide by slide is consistency. "Acme GmbH" on the title slide, "Acme" in a table on slide 7 and "Acme's CFO" in the notes of slide 12 all become "Company A". The assistant you send it to can still follow the story: which company signed, which person objected, which region grew. Add "Acme" and "Acme GmbH" to your dictionary if you want to be sure both spellings map to the same label; the tool keeps one label per value across every slide, every note and every file in the same batch.
For decks about several parties, keep an eye on labels in review: "Company A" and "Company B" should be the two competitors, not the same firm spelled two ways.
Workflow before sending a deck to an AI
The flow inside Unformation is four steps: upload, choose a rule, review, download. Around it, this is the routine we recommend for decks:
- Decide what the model needs. For a summary or a translation, the model does not need real names or the logo. For "make the tone more formal", it needs even less. Keep the ask in mind during review.
- Upload the .pptx to the PPTX anonymizer. It stays on your device; the tool shows "0 network requests" and works with Wi‑Fi off.
- Choose a rule. Labels ("Person 1", "Company A") keep the narrative readable; use redaction only for content that should disappear entirely.
- Review the findings slide by slide. Add names the patterns cannot know (people, brands, project code names) to your dictionary, or switch on the optional in-browser model for names. Untick your own company if it should stay.
- Download the anonymized .pptx and the Markdown version, plus the mapping table (CSV or JSON). Keep the mapping table local.
- Handle what the tool does not touch. Swap or remove the logo on the master, replace or delete charts that name clients, remove embedded objects, and check comments and footer text on the master slide.
- Send the anonymized deck or the Markdown. For a summary, the Markdown is often enough and smaller. For a translation, send the .pptx so the layout comes back intact.
- Restore locally. Paste the answer into the de-anonymizer with your mapping table to bring the real names back on your device.
Speaker notes: the part people forget
Notes are where presenters write what they will say, and what they will not put on the slide: "client is unhappy about pricing", "Jane is leaving in Q3", "do not mention the audit". They are invisible in slideshow mode and easy to overlook when you skim a deck, but any assistant that reads the file reads them. Unformation replaces detected values in the notes as it does on slides. Still, read the notes yourself in review: they contain judgements and context that no label can neutralize, and sometimes the right move is to delete a note rather than anonymize it.
Common mistakes
- Anonymizing the slides and forgetting the notes. Covered by the tool, but check that the notes are actually in the file you uploaded and not in a separate handout.
- Leaving the logo on the master. The text says "Company A", the corner says who Company A is.
- Trusting a chart's title. The title may be replaced; the axis labels and legend inside the chart are data, not slide text.
- Sending the mapping table with the deck. Then nothing was anonymized.
- Reusing labels across unrelated decks. "Company A" in two different decks should not be silently linked unless you intend it.
Do it now
Drop a deck into the PPTX anonymizer. It runs in your browser, keeps the design, replaces text and notes with consistent labels, and returns a mapping table you control. To see the processing pipeline in detail, read how it works.