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What a passport photo check can measure, and what it cannot
A checklist is only worth trusting if it says what it measured. OpenPhotoId runs twelve checks on every photo it makes, and each one shows its value next to the band it was judged against. This is the full list, what each check looks at, and where a checklist stops being able to help.
What gets checked is the finished file
You pick the document, then choose a photo or take one. The app finds the face, replaces the background with the colour the document names, and crops to the document's rules. The checks run after that, on the result. The face is detected again on the finished image rather than trusted from the crop, so the checklist describes the file you will actually submit.
The same twelve checks run on every document. What changes from one document to the next is the band: the allowed head height, the pixel size, the file size window.
The twelve checks, with a US passport example
These are the values a US passport photo made from a typical portrait reports. The app labels a few of the checks in plainer words, shown in brackets.
| Check | What it measures | US passport example |
|---|---|---|
| Face count | Exactly one face in frame | 1 face |
| Head height | The head as a share of the frame, against the document's band | 57.0% · band 50–68.8% |
| Eye line | Height of the eyes from the bottom edge | 62.4% · band 56.3–68.8% |
| Centring | How far the face sits off the vertical centre | 0.4% · tolerance 5% |
| Roll (Head tilt) | Head tilt, from the line between the eyes | 2.7° · max 5° |
| Glasses | Whether glasses are worn and whether they are tinted, against what the document allows | no glasses seen |
| Inter-eye distance (Distance between the eyes) | Enough pixels between the eyes for a machine to read | 98 px · min 90 |
| Blur (Sharpness) | Sharpness across the face region | variance 1147 · min 80 |
| Lighting symmetry (Even lighting) | Left/right luminance difference across the face | 8.8% · warn from 17% |
| Background uniformity (Background) | How flat the background is and how close to the required colour | ΔE 0.0 vs #FFFFFF |
| Resolution (Size in pixels) | The output size in pixels; US online renewal sets none, so this is the 2 × 2 in print at 300 dpi | 600 × 600 (300 dpi) |
| File size | Inside the portal's window, found by search rather than guessed | 200 KB · 54 KB – 10 MB |
Reading the result
The checklist ends in one of three verdicts: "Passes every check", "Passes, with cautions", or "Does not pass yet". Lighting is an example of a caution. In the US passport example the warning starts at a 17% difference between the two sides of the face.
When a check cannot be made, it says why instead of passing quietly: no face found, a face too small to measure, or no clear background above the head to sample. If more than one face is in the picture, the face count check reports how many it found and that exactly one is required.
File size works the same way. If a document sets no file size limit, the check says so. If no JPEG quality can reach the window, it says that too.
Head height, eye line and centring each have an allowed range, and the automatic crop aims for the middle of all three. Three sliders, for head size, eye height and left or right, let you move within them, and "Back to automatic" undoes it.
What the checks cannot see
The file meets the published size, background and geometry rules, and the checklist tells you which of the twelve checks passed and by how much. That is not the same as being accepted. A portal can still reject a photo for reasons no software can measure, such as an expression or a reflection on glasses. Read the checklist rather than assuming a pass.
The glasses check looks for glasses on the face and for tinted lenses, and compares them with what the document allows. None of the twelve checks looks at your expression or at a reflection on glasses. Those are up to you and the photo you start from.
Start from a photo that can pass
- Face the camera straight on, with a neutral expression.
- Use even light on your face. A window works, direct sun does not.
- Keep head and shoulders in frame, with a little room above your hair.
- A plain white or light wall behind you. Some documents, the US passport among them, do not accept a replaced background, and for those the app keeps yours and checks it.
If the original is cropped tighter than the document needs, the app extends the edges with the background colour, tells you, and the background check becomes a caution: the filled edges are not your photo. If the edge of the photo runs through the head itself, the head-height check fails, because no crop can put back a crown that was never photographed.
Several photos, one report
Choose any number of photos and one document. Every photo gets the same rules, and a CSV report says which checks each one passed. There is no cap.
Where the bands come from
Each of the 25 documents the app covers has its own bands and sizes. How the photo is made on your own device, without uploading it, is in How OpenPhotoId makes a passport photo without uploading it.
Every check is free, with no sign-up and no watermark. Make a photo at the top of the home page.