Synthetic JPEG density-metadata experiment

Run date: 2026-10-02. The source is a generated color target with no person. The 375 × 525 RGB target was encoded once as JPEG, quality 90, JFIF density 150 × 150. The JFIF density fields were changed to 72 × 72 in one copy; a second copy had only the JFIF APP0 segment removed. A separate density-150 file was retained as a comparison. The encoded scan data was not recompressed after the original save. Pillow decoded each file to RGB; SHA-256 was computed over those RGB bytes and the file bytes.

Reproduce with Python and Pillow: inspect measurements.json; the files density-150dpi.jpg, density-72dpi.jpg and density-absent.jpg. The expected result is equal decoded RGB hashes and unchanged raster dimensions, with file sizes differing only by JFIF header edits. This does not establish ERAS/MyIntealth acceptance.
