Sensor luminance pattern is like a fingerprint – courtesy Getty Images
Toronto. For years professional photographers devised various means to identify date, subject, etc., data for each negative and print. Amateurs were far less consistent, rarely ever marking negatives. Occasionally amateurs would use pencil or pen to annotate the back of their prints. Often the location, names, etc., were simply lost unless a living person had a good memory. Kodak tried to solve this lapse with their ‘autographic’ camera line that allowed a brief message to be added to each negative with a metal scribe.
When digital technology arrived and became common place, everything changed. Jerone Andrews on the 24th March 2021 via the website BBC Future has this article called “The hidden fingerprint inside your photos“. Many of us who have used Lightroom or Photos or any other program to organize digital photos, knows that standards like EXIF ‘metadata’ can add key words, descriptions, captions, camera type, exposure details, location, date and time when taken, etc. to the digital image file allowing a simple way to easily group and find images later on. Some of the data are automatic, other data can be added by the photographer. Posting images without scraping off metadata can reveal more than the uploader intended!
However, this article also identifies a far more sinister ‘fingerprint’ – the slight variance in luminosity per pixel across the sensor. This ‘map’ is unique to every sensor – just like people and their very personal fingerprints. Since sensors, unlike film, generally remain constant for a given camera, the pattern allows forensic analysts to not only identify which camera took the image, but whether the image was manipulated once saved.
Read the above article to see just how such metadata and patterns can reveal far more than was intended. A big thank you to my good friend and fellow PHSC member, George Dunbar, for spotting this timely article in his pursuit of photographic history.
N.B. The title reminds me of the Leonard Cohen poem and song called “fingerprints“. I first read the poem many decades ago and later on picked up the CD with him singing the words.
