About Slide Watermark Remover

Slide Watermark Remover is run by an independent developer. It is not affiliated with, endorsed by or sponsored by Gamma Tech, Inc. or Google LLC; Gamma and NotebookLM are their trademarks and are named only to describe which files the tool handles. You are responsible for complying with your own plan and licence terms. Questions, bugs and billing: support@slidewatermarkremover.com.

PowerPoint (.pptx)

The deck is unzipped in memory with JSZip. Every slide, slide layout and slide master is parsed as XML. Shapes, pictures and groups are removed when they link to gamma.app or notebooklm.google, or when their whole text is a badge phrase such as “Made with Gamma” and they sit in the bottom-right corner. Slides that are one full-slide picture (as in NotebookLM exports) have that picture decoded, its corner rebuilt and the picture written back in the same format. The archive is then zipped again.

PDF

The PDF is opened with pdf-lib. Link annotations pointing to gamma.app or notebooklm.google are deleted. Pages that are one full-page image have that image decoded and its corner rebuilt in place, at the original resolution. On pages with real text, the corner box is rendered with PDF.js, rebuilt, and the clean patch is drawn over exactly that box.

Images (.png, .jpg, .webp)

The image is decoded on a canvas, the corner is rebuilt, and the image is saved again in its own format. Only the pixels of the mark change.

Video (.mp4)

Five frames are sampled to find the pixels of the mark that stay put while the slides change. Every frame is then decoded with WebCodecs, the same pixels are rebuilt, and the frames are encoded again. The audio track is copied without re-encoding.

Rebuilding the corner

1. A smooth background model (a quadratic surface for each colour channel) is fitted to a ring of pixels just outside the box, ignoring outliers such as slide content that touches the ring.
2. Pixels inside the box that differ clearly from that model are the mark; they are grown by 2 px to include anti-aliased edges. Pixels that do not stand out are left untouched.
3. Each marked pixel is rebuilt by interpolating between the nearest clean pixels to its left and right and above and below, then smoothed with a few Laplace passes so no seams remain. On flat and linear-gradient backgrounds this reproduces the background exactly; our tests require a difference below 3 colour levels.

1. Open this site in Chrome or Edge on a computer.
2. Open the developer tools (F12, or Cmd+Option+I on a Mac) and go to the Network tab.
3. Drop a deck, PDF, image or video into the tool and press Remove watermark.
4. Look at the Size column. You will see the tool’s scripts load, small requests to /_serverFn that check your free exports, and nothing the size of your file.
5. To be strict: after the file has opened, switch the Network tab to Offline. Previewing, cleaning and downloading still work.

• Marks over busy photos or patterns: the rebuilt pixels are smooth, so they can look softer than the photo around them. Keep the box tight around the mark.
• The invisible SynthID watermark that Google can embed in generated images and video is not touched.
• Encrypted (password-protected) PDFs cannot be edited.
• Old .ppt files need to be saved as .pptx first; video must be MP4.
• Video needs WebCodecs (recent Chrome or Edge on a computer). Some phones cannot encode video in the browser.

Free

Two exports a day without an account. One export is one downloaded file: a whole deck, a whole PDF, an image or a video. Opening files, previewing and the sample files are free. The count resets at 00:00 UTC and is kept per account when you are signed in, otherwise per one-way hash of your IP address.

Pro

Unlimited exports for $4.99 a month or $29.99 a year, through Stripe. Files are processed the same way on both plans.

Cancel

Sign in, open Settings → Billing and press Manage subscription. You keep Pro until the end of the period you paid for.