Optography: Can a Victim's Eye Photograph the Killer? History, Science and Failures of a Forensic Illusion

In 1938 former Scotland Yard inspector Walter Dew, the man who arrested Dr Crippen, published his memoirs. Recalling the morning of 9 November 1888, when he entered the room in Miller's Court where Mary Jane Kelly, the last canonical victim of Jack the Ripper, lay dead, he wrote that her eyes were photographed as a "forlorn hope". The idea was that the retina might keep the last image it saw: the killer's face.

In my Jack the Ripper case file I mentioned this episode in two lines. It deserves much more, because optography is one of the most instructive stories in criminalistics. It is not a legend born from nothing: at its origin lies a genuine scientific discovery, and a German physiologist really did fix images in the eye of an animal and of a man. The problem was the leap from the laboratory to the crime scene.

As an investigator and a photographer, I approach it as a technical file: what was claimed, what was proven, why it could not work and what remains of it today.

1. The promise: a witness who cannot lie

The idea is simple and very powerful. The eye works like a camera: the lens is the objective, the retina is the film. If at the moment of death the "film" stayed exposed, you would only need to develop it to get a perfect witness: the last thing the victim saw.

In the nineteenth century the idea was believable for three reasons:

• photography was a young and almost magical technology, able to fix reality on a plate;
• physiology was genuinely discovering the chemistry of vision;
• the police did not yet have reliable scientific tools: fingerprints only entered investigative practice between the late nineteenth and early twentieth centuries.

A chemical witness, impossible to bribe or frighten, was every investigator's dream.

2. Before the science: the rumours (1856–1870)

Optography was born as a newspaper story before it was an experiment.

The French case is the most important, because it marks the first scientific check of the idea. In 1869 the Paris Society of Legal Medicine asked physician Maxime Vernois to investigate. Vernois spotted the problem at once: Bourion had photographed the eyes 50–52 hours after death. Then he ran an experiment: he killed sixteen animals, photographed their retinas and saw only the anatomy of the retina, no image. He concluded the claim was false and published his results in 1869–1870.

The investigator's lesson: as early as 1870 someone had done the right thing, a controlled experiment. But the refutation never got the same echo as the sensational news. It is a script we know well.

3. The real discovery: visual purple

A few years later, physiology gave optography a real basis.

Boll and "visual red" (1876)

On 12 November 1876 German physiologist Franz Christian Boll, working in Rome, reported a discovery to the Berlin Academy of Sciences: the rods of the frog's retina contain a red pigment that bleaches in light and regains its colour in the dark. He called it Sehrot, "visual red". Boll died in Rome in 1879, aged thirty.

Kühne and the optograms (1877–1880)

The discovery was taken up by Wilhelm (Willy) Kühne (1837–1900), professor of physiology at the University of Heidelberg. Kühne renamed the pigment Sehpurpur, "visual purple", and coined the term we still use today: rhodopsin.

On 5 January 1877 he presented his first results, reported on 1 February by the journal Nature. His findings were three:

1. visual purple survives death, if the retina is protected from light;
2. its regeneration after bleaching depends on living tissue behind the retina (today we would say the pigment epithelium);
3. to obtain a permanent image, the light has to be so prolonged or so intense that it bleaches the pigment faster than it regenerates.

Kühne called the fixed image an optogram and the procedure optography.

The rabbit experiment

The classic method, described decades later by Nobel laureate George Wald, went like this:

1. the head of an albino rabbit was covered, to adapt its eyes to darkness;
2. the head was fixed facing a barred window for about three minutes;
3. the animal was decapitated and the back half of the eye removed, working under red or yellow light;
4. it was placed in an alum solution, which fixed the image;
5. the next day, the bars of the window could be clearly seen on the retina.

The first images were tiny, about one square millimetre. In rabbit eyes an optogram could be obtained up to 60–90 minutes after death; in ox eyes, after an hour, nothing could be obtained at all. Chemist Robert Bunsen watched some of the experiments. According to an account reported by historians of science, an attempt to "photograph" physiologist Hermann von Helmholtz in a rabbit's eye showed only his white collar: the only element bright and contrasted enough.

Kühne himself warned against popular interpretations. The retina, he wrote, is not a fixed photographic plate but "a photographic workshop, in which the workman continually renews the plate".

4. The only human optogram: Bruchsal, 16 November 1880

The decisive step was to try on a human being. The opportunity came in 1880.

Erhard Gustav Reif, aged about thirty-one, convicted of drowning his children, was guillotined at Bruchsal, in Baden, on 16 November 1880. Kühne obtained the body and worked under red and yellow light. He removed the left retina about ten minutes after the blade fell and treated it with his method.

He obtained a sharp optogram, a few millimetres across. But his conclusion is a model of scientific honesty: "A search for the object which served as source for this optogram remained fruitless." In other words: there was an image, but nobody knew what it showed. All that survives of that optogram is Kühne's drawing, published in 1881.

Later it was claimed that the image showed the guillotine blade. That is impossible: Reif was blindfolded. Others have suggested the steps of the scaffold. Kühne offered no interpretation.

In 1881 an American physician who had worked with him, W. C. Ayres, wrote in the New York Medical Journal that it was "utterly idle to look for the picture of a man's face" on the retina of someone who dies suddenly.

5. Why it could not work: the physics of a self-reloading film

As a photographer, the clearest way to explain the limits of optography is to compare the retina to film. But it is a very strange film.

To these limits add two more, of pure optics:

• Resolution. The area of sharp vision in the human retina, the fovea, measures about 1.5 millimetres. Optograms are tiny and blurred: even at best they show basic shapes, such as bars or bright squares, not facial features.
• The image is inverted. As in any camera obscura, the image on the retina is upside down and reversed left to right.

Finally, there is a methodological error that, as an investigator, I consider the most serious. Photographing a corpse's eye from the outside has nothing to do with Kühne's optography. Kühne removed the retina and fixed it chemically in the dark. The police photographs of victims' eyes showed at most the surface of the eye, with its reflections: nothing of what was inside.

6. The police believed it anyway

Despite the scientists' warnings, for half a century the idea entered practice and, above all, the crime pages.

The Angerstein case is a perfect example of how a forensic myth is born: a conviction obtained with real methods, such as fingerprints, is reported by the press as a triumph of the impossible method. And once printed, the sensational version outlives the true one.

Optography also had a disturbing side effect: according to some authors, certain criminals began destroying their victims' eyes for fear of being "photographed". The most cited case is that of Constable George Gutteridge, killed in England in 1927 with a shot through each eye. But the link to optography is a hypothesis, not an established fact.

7. The final verdict: Heidelberg, 1975

Almost a century after Kühne, at the same university, the police once again asked science whether optography could help. In 1975 ophthalmologist Evangelos Alexandridis, of the University of Heidelberg eye clinic, repeated the experiments on anaesthetised rabbits.

He obtained clear optograms, fixing the retina in alum for 24 hours and photographing it immediately because the image faded. His conclusion was clear-cut: the method has no forensic value. The phenomenon is real, but only under conditions that never occur at a crime scene.

8. When fiction outruns science

If optography survived so long, it is also thanks to literature and cinema, which turned a laboratory phenomenon into a narrative device.

It is a classic example of a vicious circle between science, press and fiction: the real discovery inspires the press, the press exaggerates, fiction makes the idea familiar, and the public, and sometimes the police, end up believing it.

9. The real heir: reflections in the eyes

Optography is dead, but the idea that eyes can "testify" has a serious scientific heir, and it is tied to my profession.

In 2013 two psychologists, Rob Jenkins (University of York) and Christie Kerr (University of Glasgow), published a study in PLoS ONE titled Identifiable images of bystanders extracted from corneal reflections. Using high-resolution portrait photographs, they zoomed into the reflection on the subjects' corneas and recovered images of the people standing in front of them. Those faces were about 30,000 times smaller than the subject's face, and yet:

• people who did not know them matched them correctly 71% of the time;
• people who knew them recognised them 84% of the time.

"The pupil of the eye is like a black mirror," Jenkins explained. The authors suggested applications in cases such as hostage-taking or child abuse documented in photographs.

The difference from optography is fundamental: nothing here is "stored" in the eye. It is optics, not chemistry: the reflection exists only at the instant the picture is taken, on a living eye, and the photograph captures it. It is the modern, realistic version of the nineteenth-century dream.

In OSINT image analysis this principle is invaluable. Reflections in eyes, glasses, windows, mirrors, car bodies and screens can reveal who took a photo, who was present, where it was taken and at what time. It is one of the first things I check when I analyse a photograph for an investigation. It is also a warning for anyone who posts high-resolution photos online: they can tell much more than meets the eye.

10. What optography teaches investigators

Optography was born from a real discovery, rhodopsin, which paved the way for the modern understanding of vision. It failed as a forensic tool because people demanded more from science than science could give. It is the same temptation I described when discussing the shawl DNA attributed to the Ripper and the evidence on Hitler's death: scientific evidence is only as good as the conditions under which it is gathered.

That is the approach I bring to my investigations and OSINT analysis, and the one I use as a photographer: an image tells the truth only to those who know what it can and cannot show.

Main sources: Nature, 1 February 1877, report on Kühne's research; Arthur B. Evans, "Optograms and Fiction: Photo in a Dead Man's Eye", Science Fiction Studies 20.3 (1993); Douglas J. Lanska, "Optograms and criminology: science, news reporting, and fanciful novels", Progress in Brain Research 205 (2013); Nicholas Wade, Perception 37 (2008); Maxime Vernois, Bulletin de la Société de médecine légale (1869) and Revue photographique des hôpitaux de Paris (1870); R. Jenkins and C. Kerr, PLoS ONE 8(12): e83325 (2013); Smithsonian Magazine, McGill Office for Science and Society and American Academy of Ophthalmology on police cases; contemporary newspapers cited in the reconstructions by Digging History and jack-the-ripper-tour.com.