Got some glass plate negatives? Used until the 1920s, you can totally digitize them! We recommend using either a camera or a scanner, and here are a few tips on how to get the best results.
Glass negatives appeared with the wet collodion process in 1851. Photographers had to prepare their own plates before taking pictures. From the 1880s onwards, this technique was replaced by dry plates coated with a gelatin emulsion of silver bromide. These were manufactured industrially by Agfa, Eastman, Gevaert, Ilford, Lumière, etc. in a wide variety of formats, from 4.5 x 6 cm to 50 x 60 cm (non-exhaustive list). In France, the formats most commonly found in attics and at second-hand dealers are 6.5 x 9, 9 x 12, and 13 x 18 cm. These were in turn eclipsed by film in the 1930s.
Fragile but stable
Glass negatives are fragile, as evidenced by this famous view of Paris taken in 1929 by André Kertes. But unlike film, plates are easier to digitize because the negative remains flat and rigid. There are two approaches: using a digital camera or a scanner. For a digital camera, a macro lens is essential. A normal focal length lens equipped with an extension ring does not offer the same sharpness. Ideally, a reproduction stand should be used to optimize the parallelism between the sensor and the negative. A camera mounted on a column makes framing easier.
Alternatively, a tripod secured to the edge of a table will suffice.
Depending on the brand, glass negatives are between 1 and 2 mm thick. They are perfectly flat.
The most matte side is the emulsion side.
Backlighting
For optimal backlighting of the negative, an LED light table is recommended, with a suitable color temperature ranging from 5000 K to 6500 K. Crucially, the light distribution must be uniform. Industry-standard options include the Kaiser Slimlite Plano or the Dörr Light Tablet Ultra Slim.
Since these light tables are typically larger than the glass plates, light spill (flare) from areas outside the negative can occur. To mitigate this, a piece of black material (such as paper, cardboard, or plastic) with a window cut to the exact size of the plate should be placed over the light table.
To prevent unwanted reflections on the image, the emulsion side of the plate—which is noticeably more matte than the glass backing—should be oriented toward the camera. Further control of stray light can be achieved by working in a dark room or by fitting a piece of black cardboard, cut to the diameter of the lens, around the camera lens.
To further reduce lens flare, surround the negative with black cardboard.
Camera and Raw format
With the camera in a stable position, shooting in Raw format at the camera’s lowest ISO sensitivity offers more flexibility in post-production than JPEG. The lens is set to its best aperture to take advantage of its optimal resolution, usually around f/8 with a macro lens and a full-frame sensor camera. A remote shutter release is recommended to avoid vibrations. Using tethered capture software like Capture One or Lightroom can significantly speed up the process when digitizing a large quantity of glass plates. And this is the ideal opportunity to organize and classify your glass and film archives.
When the plate is shot in the inverted position (with the emulsion gelatin facing the lens), the resulting image must be flipped in Lightroom or Photoshop.
Scanner and Raw format
Digitizing glass plate negatives can be challenging, especially when considering the equipment and setup required. Setting up a reproduction stand can be impractical due to space constraints or the lack of a suitable macro lens. Consequently, a flatbed scanner is often the preferred alternative, provided its scanning bed accommodates the plate size.
Older models, such as the Epson Perfection V600 Photo, are limited to transparencies 6 cm wide. While it is possible to scan larger plates in multiple sections and stitch the images in post-production, this process is laborious. Scanners with an A4 scanning area, like the Epson V850 (or V700, V750, V800), offer a better solution. Note that both the V600 and V850 models were discontinued by Epson in early 2025. The Microtek ArtixScan F2 is a contemporary alternative.
Given the potentially high density and contrast of glass plate negatives, it is recommended to digitize them as DNG files using software like Silverfast SE or SE Plus to maximize the scanner’s dynamic range capture.
Place the glass plate so that the emulsion side is directly against the scanner glass.
Ensure the scanner glass is clean to prevent dust marks.
To maximize the dynamic range of your scanner (e.g., an Epson V700) when scanning high-density, high-contrast negatives, use Silverfast to scan in Raw DNG format. A resolution of 1200 dpi is appropriate for the 9×12 cm negative format.
Image inversion
When digitizing a negative, whether with a camera or a scanner using Silverfast in Raw DNG format, the resulting image is saved with inverted tonal values (as a negative). Therefore, the image must be inverted. Before inversion, it is recommended to convert the image to black and white to eliminate any color cast from the light source. In software like Lightroom, the easiest way to invert the image is using the curve in the development module: raise the black point to the top and lower the white point. This must be done individually for each RGB channel. The main channel (indicated by a gray disc) maintains its original curve shape and can be adjusted afterwards to refine the brightness and contrast of the image.
Developing the image with a black-and-white profile should be done before inversion to eliminate any unwanted color casts.
In Lightroom, the process of reversing a negative to a positive image is achieved by manipulating the RGB channel curves. The primary curve is preserved for subsequent adjustments.
Discover the photography courses at Spéos
Spéos offers various training courses ranging from simple one-week photography workshops (initiation and advanced level) to 3-year courses. The long courses to become professional photographers allow you not only to master all the photographic techniques and its vocabulary (blurs, hyperfocus, sharpness zone, depth of field, backlighting, focal length, shutter release, autofocus, wide-angle, rule of thirds, etc.), but also all the stages of shooting and image processing.
Visiting the school allows you to discover the premises, the studios and the equipment, and is undoubtedly the best way to familiarize yourself with your future way of working. This is why, in addition to the open days, Spéos offers throughout the year personalized visits by appointment to come and discover the school with a member of the team.
Text and photos: Philippe Bachelier, teacher of Printing techniques at Spéos