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The Probebild in raking light. Add the file to the site folder and set the video path in Tweaks.
Zenker, Wilhelm. Lehrbuch der Photochromie (Photographie in natürlichen Farben) nach den wichtigen Entdeckungen von E. Becquerel, Nièpce de St. Victor, Poitevin u. A. Nebst einer physikalischen Erklärung des Entstehens der Farben. 8vo. Berlin: Selbstverlag des Verfassers, 1868. First edition.
Containing what we believe to have been the first direct color photograph ever issued in a printed book — an experimental and unfixed silver-subchloride color Probebild made in 1867, of the Poitevin type. Zenker printed the book at his own expense; forty years later Gabriel Lippmann won the Nobel Prize in Physics for interference color photography, and in his Nobel lecture he dismissed Zenker’s explanation of Becquerel’s results while calling the interference layers at the heart of his own method Zenker’s laminae — the theory vindicated, though not where Zenker had aimed it. An extraordinarily improbable survivor in any state, from a photographic tradition whose few surviving specimens appear to have gone unremarked in the standard histories. We have located three other copies retaining the Probebild — at the Humboldt-Universität zu Berlin, the Deutsches Museum, and the British Library — examined in digitised form; and no other copy of the 1868 edition, complete or not, in the trade. The subject of Episode No. 2.
This copy has spent its life among people who worked with light, and it survived against the odds, one suspects, because each of them understood what they had.
Its first recorded owner stamped the title page Felix Fritz, Dipl.-Ing., a title which originated in Prussia in 1899 and which he gave up for Dr. in 1926. Fritz was a German industrial chemist and historian of chemistry who wrote on the oldest question in photochemistry — who first saw light darken silver — and was answered in print by Josef Maria Eder, the great historian of photography. Zenker’s experiments fell squarely within his subject, and only the 1868 edition carries the color specimen.
It next appeared with two Swiss photographers, René Mächler of Zürich and Roger Humbert of Basel, founding figures of Concrete Photography, which abandoned the camera to make images from light itself. Zenker’s book explains how light, thrown back on its own path, writes its wavelength into a layer of silver. Whether either artist read it as a text for their own work we cannot say; that they owned it, and passed it between them, we can.
It surfaced in Basel in the 2020s and came to us from there. The chain runs from a chemist who studied the birth of photochemistry to two artists who practiced its purest form — an unusually cohesive and fitting provenance.
Later half red cloth over red and gold decorated paper boards, red cloth corners; approx. 228 × 162 mm. Lightly rubbed at the extremities, small chip to the fore-corner of the upper board; text block sound. Wood-engraved figures in the text, printed white on black, including the standing-wave diagram at p. 78. Scattered foxing and light marginal damp staining throughout, heavier toward the front; title page with light foxing, a pale damp stain to the left margin, and minor fraying at the upper fore-corner.
Issued, as the title page states, with a photograph in natural colors as a Probebild and a lithographed plate in color printing. The lithographed plate — a solar spectrum on black card, the Fraunhofer lines lettered A to H — retains its full strength of color, sharp and unfaded; its leaf, however, is heavily damp-stained, with broad tide-lines and associated foxing across most of the sheet.
The Probebild, a separate sheet tipped onto a mount leaf, survives as a legible tonal image of a floral still life: a spray with two large blooms at center, radiating foliage, spiked flowers at the upper corners. The sheet has shifted overall to a warm reddish-brown and no discrete hues remain separable — measured across the specimen, design and ground differ in lightness but not in hue, the image now carried by tone alone. It reads clearly across the central third and is progressively obscured toward the edges by darker oxidation, heaviest along one margin and the opposing corners. Best seen in raking light; largely illegible in flat frontal light. Minor surface abrasion at one edge, a light handling crease, a small loss at one corner; edges irregular, hand-cut. Verso blank with minor surface scratching. Tissue guard intact. Housed in an archival box against further light exposure.
The Probebild is not measured here: the specimen is unfixed and remains light-sensitive, and it is kept in an archival box and unexposed. Dimensions and any further examination can be arranged for a serious enquirer under controlled conditions.
The specimen has not been examined spectroscopically. Reflectance or multispectral imaging would establish whether any differential pigmentation survives below the visible threshold, and we would welcome the involvement of an institution equipped to undertake it.
Provenance: Felix Fritz, Dipl.-Ing. (ownership stamp to title page, fl. 1899–1926), Berlin; René Mächler (1936–2008), Zürich (ex libris stamp); Roger Humbert (1929–2022), Basel (blind-stamp, and ink signature to the front free endpaper); acquired by the present owner, 2026.