SynthID

SynthID detector

What Google's watermark can tell you, and what to do when it can't.

Pending Google approval

In short

What is SynthID?

SynthID is an invisible watermark that Google DeepMind adds to images made by its AI models; OpenAI now adds it too, and Google offers its own SynthID detector. Perspicax supports SynthID. Until activation, its results come from Content Credentials and TrueEye 2.1, which detects AI images from the pixels even when a watermark or label is missing.

What SynthID does

Google adds SynthID to every image its models generate, including Nano Banana. It sits in the pixels rather than in the file's metadata, so it can survive a re-save that strips Content Credentials.

Not every generator uses it. OpenAI has added SynthID to ChatGPT images; ByteDance's Seedream does not use it.

How to check an image for SynthID

Google's SynthID portal (synthid.com) is open to anyone who signs in, and the Gemini app can answer "Was this created with Google AI?". Both look only for the watermark: they are not general AI detectors, and they don't say which company's model made the image.

Where Perspicax fits

Perspicax supports SynthID, Google's invisible watermark for AI images. Until activation, results come from TrueEye 2.1, which detects AI images from the pixels even when a watermark or label is missing, and from Content Credentials (C2PA), read on every upload. In testing, TrueEye 2.1 caught 93.6–98.3% of Gemini images (Nano Banana, Imagen).

Content Credentials (C2PA)Live
SynthID watermark checkSupported

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Questions

Does Perspicax detect SynthID?

Support is built in and pending Google's approval; until it's active, results come from TrueEye 2.1 and Content Credentials.

How can I check if an image has SynthID?

Use Google's SynthID portal or ask the Gemini app; both look for Google's watermark only. Perspicax supports SynthID checks too.

Which generators use SynthID?

Google's own models, including Nano Banana and Imagen, and OpenAI's ChatGPT images. ByteDance's Seedream does not use it.

Can SynthID be removed?

It is designed to survive re-saves and most screenshots, but no watermark is impossible to weaken. That is why a detector should not rely on one signal; Perspicax checks the pixels too.

If SynthID isn't found, is the image real?

No. Most generators don't use SynthID, so a missing watermark proves nothing. Check the pixels as well.