Types of Photo Slides

June 24, 2021

Long before 35mm slides were introduced, "magic lantern slides" were considered cutting-edge media. Introduced in 1849, these slides usually came in strips with multiple images. They are constructed from a base piece of glass with the emulsion (photo or imagery), a flimsy cardboard frame, and a top piece of glass protecting the strip. Sometimes hand-colored tinting was added, although this is more common in slides depicting illustrations. If you find any today in good condition, count yourself lucky because they’re fragile, and many have cracks and mold.

A newer invention that gained popularity in the late 1940s, stereo slides are created from two images taken simultaneously with a special camera. The rectangular mounts include two identical images slightly offset from one another to create a 3D effect. While lantern and stereo slides are interesting pieces of photographic history, more than likely, you’ve discovered far more common photographic slides among your family heirlooms, like 35mm. On occasion, you might be lucky to inherit larger slides, especially if one of your family members was a serious amateur photographer.

Guide to Common Types of Slides

Standard 35mm Slides: Kodak introduced 35mm slide film in 1935, and slide projectors gained popularity starting in the 1950s. If you grew up in the 1960s, you might remember family slideshows in which everyone gathered together to watch carousels of slides depicting family vacations and other subjects. (Inevitably, a few slides would be upside down in the carousel, and everyone would utter a collective groan!) Vintage 35mm slides are usually “a dime a dozen” at garage sales and thrift stores and often are sold in full slide projector carousels. Production of 35mm slide projectors ended in 2004, while Kodachrome film was discontinued in 2009.

Slide mount size: 2” x 2”
Transparency film size: 24mm x 36mm
Film: Ektachrome, Kodachrome

126 Slides: Produced by Kodak in 1963 for Instamatic cameras, the transparency is a perfect square inside the mount. This format was popular because it was easy to pop a cartridge into the camera and remove it after all the frames were exposed.

Slide Mount: 2” x 2”
Transparency Film Size: 28mm x 28mm

110 Slides: Introduced by Kodak in 1972, 110 is a miniaturized version of Kodak's 126 film format used in pocket Instamatic cameras. At half the size of 35mm slides, this film is typically grainy and lacks sharpness.

Slide Mount: 2” x 2”, less often 1” x 1”
Transparency Film Size: 13mm x 17mm

127 Slides: Produced by Kodak from 1912 to 1995, the transparency is a perfect square that fills out the mount far more than the 126 format. The 127 slides are considered medium format and were dubbed Vest Pocket Film based on Kodak’s Vest Model camera. In the 1960s, this film decreased in popularity due to the success of 35mm film.

Slide Mount: 2” x 2”
Transparency Film Size: 40mm x 40mm

120/220 Slides: This medium format slide film was used in many cameras, most notably several different 120/220 models from the camera manufacturers Hasselblad, Mamiya, Pentax, Bronica, and Rollei. The slide sizes can vary because the images are spaced out differently on the film; however, one side is always exactly 2.25 inches.

Slide Mount: 2.75” x 2.75”
Transparency Size: 2.25 x 2.25”

Converting Old Slides to Photos

Slides are easily damaged, colors change, and how many people have a working slide projector these days? Digitization is the best way to preserve, enjoy, and share old slides with others. Only a handful of consumer film/slide scanners are available on the market that handle anything larger than 35mm, and they’re extremely costly. The best way to view old slides is to get them scanned professionally. At ScanDigital, we have sophisticated scanning equipment that can handle 35mm, the 110 format, 126mm, 127mm, 2.25", and even stereo slides (we scan just one image).