# Technical Guides

Background on the formats, watermarks and forensic techniques that decide whether an image reads as camera output.

- [How the SynthID watermark works](https://passreal.com/guides/synthid): SynthID is Google's watermark for AI media, embedded in the pixels rather than the metadata. What Google says it survives, how it is checked, and what we know.
- [What is C2PA metadata?](https://passreal.com/guides/c2pa): C2PA is a signed provenance record attached to an image. What a manifest holds, why it is tamper-evident, why it can still be removed, and what it proves.
- [Why AI detectors flag real photos](https://passreal.com/guides/false-positives): AI image detectors return a probability, not a fact, and real photos get flagged. The common causes, what you can check yourself, and what to do if it happens.
- [Does EXIF data prove that a photo is real?](https://passreal.com/guides/exif-authenticity): EXIF is unsigned text that any tool can write. What camera metadata can suggest, what it cannot prove, and which signals are stronger evidence of a real photo.
- [How JPEG quantization tables identify the device that wrote a file](https://passreal.com/guides/jpeg-quantization-tables): A JPEG carries the tables used to compress it. Manufacturers use their own, so the table identifies the software or the body that wrote the file.
- [Frequency-domain artifacts in generated images](https://passreal.com/guides/frequency-artifacts): A 2D Fourier transform of a generated image shows regularly spaced peaks that photographs do not have. Here is where they come from and how to see them.
- [The artifacts a diffusion model leaves in an image](https://passreal.com/guides/diffusion-artifacts): Latent diffusion decodes through a VAE, and the decoder leaves its own traces: flattened texture, over-smooth gradients and a characteristic noise floor.
- [How to remove AI metadata from an image](https://passreal.com/guides/remove-ai-metadata): C2PA manifests, XMP blocks and PNG text chunks record that a file was machine made. Exiftool and screenshots strip some of it by hand, each with real limits.
- [Why Instagram and Facebook put an AI info label on a photo](https://passreal.com/guides/instagram-ai-label): Instagram reads C2PA and IPTC digital-source-type fields written by generators, not the pixels. Strip that metadata and the automatic label has nothing to read.
- [How to remove an AI watermark from an image](https://passreal.com/guides/remove-ai-watermark): There are three kinds of AI watermark: a drawn logo, data in the file, and a signal in the pixels. How to tell which one you have and what can be removed.
- [Can you remove SynthID from an image?](https://passreal.com/guides/remove-synthid): Honest answer on removing SynthID: no tool can promise it, and Google says it resists edits. What you can remove next to it, and what PassReal guarantees.