Why Calibration Matters

When you print a passport photo at home, the printed size depends on your printer settings, paper size, and the DPI of the image. Without calibration, photos often come out too large or too small — which means rejection at the passport office.

Our calibration ruler solves this in three steps.

Mode 1: Screen Calibrate

This mode calibrates your screen's pixel density (PPI). Here's how:

  1. Open the editor and tap the ruler icon
  2. Select Screen Calibrate
  3. Hold a standard credit card (85.6 × 54 mm) against your screen
  4. Drag the slider until the on-screen ruler matches the physical card width exactly
  5. Tap Save — your screen PPI is now stored

This ensures the on-screen preview shows your passport photo at the correct physical size.

Mode 2: Print Calibrate

This mode calibrates your printer's DPI output:

  1. Print the calibration test sheet (a single page with a ruler)
  2. Measure the printed ruler with a physical ruler
  3. Enter the measured length in the calibration tool
  4. The tool calculates your printer's actual DPI and adjusts all downloads accordingly

This step is only needed if you're printing at home. Photo labs (Walgreens, CVS, etc.) print at exactly 300 DPI.

Mode 3: Compliance Check

This mode overlays the ICAO biometric face guide on your photo to verify:

  • Head height percentage (chin to crown vs. total photo height)
  • Face centering — eyes must be in the upper third of the photo
  • Eye line horizontal alignment
  • Head tilt angle

Green overlays mean compliant. Red overlays highlight what needs adjustment. Drag and zoom your photo until all overlays are green.

Tips for Perfect Prints

  • Always use matte photo paper — glossy paper can cause glare that scanners reject
  • Print at 300 DPI minimum — never scale up a low-resolution image
  • Use your printer's "Best" or "Photo" quality setting
  • Trim the photo with a sharp blade and metal ruler for clean edges