Preparing a source and protecting true size

What you are trying to accomplish

Create a source image that PatternForge can relate to real-world measurements and that clearly shows the entire pattern boundary.

Why it matters

A photo contains pixels, not physical dimensions. PatternForge needs a trustworthy reference in the same plane as the pattern to know how large those pixels should be. A small scale error affects every edge, marking, and printed page that follows.

Photo distance

Known real size

Step by step

1. Print the PatternForge sizing card for the paper size you actually use.
2. Print at Actual size or 100%, never Fit to page.
3. Measure the card’s printed check and stop if it does not match its stated size.
4. Place the pattern and card flat on the same surface.
5. Use even light and a contrasting background.
6. Keep every card target and the full pattern outline in frame.
7. Hold the camera as square to the surface as practical and avoid motion blur.
8. In PatternForge, set true size and complete the independent verification step.

What success looks like

The card is fully visible, the pattern edge can be distinguished from the background, the image is not blurry or cropped, and PatternForge reports that true size was independently checked for that photo.

Common problems and recovery

• Wrong paper size: print the matching card or restart calibration with the correct selection.
• Card is cropped: retake the photo; guessing hidden corners is unsafe.
• Glare or low contrast hides an edge: move the lights or change the background.
• Pattern and card sit at different heights: place them on the same flat plane and recapture.
• Verification fails: inspect the printed card, corner placement, and photo perspective before retrying.

Quick safety check

Do not trace a photo-based piece for final use until both the physical-ruler entry and PatternForge's matching photo-line check pass.

Related tools and next step

Use Print the sizing card, Capture a clear photo, and Set and check true size.