RAWEngine

Content checked against the RAW itself

• With the RAW uploaded and its sensor data verified, the photo is checked for content changes against the RAW itself, not only the camera's small preview. Lifted shadows, recovered highlights and strong grades are no longer mistaken for changes, because the RAW holds the detail the preview had lost.
• A changed area is reported only when two independent checks agree: the difference in what the photo shows, and the direction its edges run. Tone edits change how strong edges are, not which way they run.
• Structure is compared above the scale of sharpening, clarity and noise, so strongly edited photos are judged fairly.
• The RAW is lined up with the camera's own preview to the pixel, so lenses that rely on in-camera correction (such as Nikon Z) no longer leave the corners out of line, and the lens is fitted again against your JPEG.
• Changed areas are outlined along the edit's own edge, from a pixel-by-pixel comparison with the RAW; separate edits get separate outlines. Where that comparison can't be trusted (black-and-white conversions, very strong local contrast), the broader outlines stay.
• A new layer on the result page, "Difference from the RAW", shows where your JPEG differs from the RAW after matching your exposure, colour and tone.
• Local tone is measured up to the frame's edges, so a vignette counts.
• A content change costs 20 points plus 4 per % of the frame.
• Content Credentials whose signature doesn't cover the image are refused, and revoked signing certificates are recognised.
• Tested on 1,608 finished photos from six real shoots, delivered to clients, before release.

The preview is checked against the sensor, area by area

• With the RAW uploaded, the camera's own preview is compared with the sensor data area by area, not only as a whole: an edited preview no longer earns "Captured by a camera". The comparison first matches the camera's own rendering (tone curve, colour, local tone such as Active D-Lighting, lens correction), so honest photos from any camera are not held back.
• The preview sent with an upload must be the one stored inside the RAW file.
• Faces in the photo are compared with the faces the camera captured, by identity: a swapped face is a content change. A face that can't be found on both sides is "not checked", never a pass.
• A new content check, calibrated on real photo shoots: heavy black-and-white, contrast and local-tone edits no longer count as content changes, removals on heavily edited photos are found by comparing the local structure of the image, and thin shapes such as a drawn line are kept.
• Changed areas are outlined on the certificate and the content penalty grows with their share of the frame.
• Camera and lens names match when one contains the other as whole words ("XF35mmF2 R WR" and "Fujifilm Fujinon XF35mmF2 R WR").
• When the photo or the sensor data can't be lined up with the camera's preview, nothing is rated and nothing is claimed: "not matched" or "not checked", never "does not match".
• A preview or JPEG that is incomplete (an interrupted copy) is refused at upload with the reason, instead of failing later.
• Each check shows the value it was decided on.

Sensor forensics and camera details from the RAW

• The undeveloped RAW data is checked for the signs of a real sensor: how its values are spread, how noise follows the light, whether the noise fits the ISO, and whether the photo shows a screen or a print.
• The preview inside the RAW is checked against the camera model's own JPEG encoder, and the final JPEG for traces of an earlier save.
• With the RAW uploaded, the camera, lens and settings are read from it on our server, and any difference from what the browser sent is reported.
• Nikon High Efficiency RAWs (Z 6III, Z 8, Z 9, Z f) are decoded and checked.
• RAW formats that can't be decoded yet are reported as "not checked", never as a failure.

Comparison with the camera's own preview

• The photo is aligned with the preview the camera stored in its RAW file, and crop, rotation, perspective, global and local tone, and detail are measured.
• Anything added, removed or altered is marked.
• The fidelity score: 100 minus a penalty for each kind of edit.
• Every claim a certificate makes is listed as passed, failed or not checked, with the reason.
• Content Credentials (C2PA) in the RAW and the JPEG are read and verified.