|A 1960’s magazine ad for Kodak’s various lines of slide film.
Image courtesy of Nesster
Slide film, otherwise known as positive, reversal or transparency film (and occasionally as ‘E-6’ for its development process), was the choice of ‘pro’ shooters back in the pre-digital film photography days. What’s the difference between slide and print film? Simply, print film produces a negative image, while slide film produces a positive image.
Individual frames of developed slide film can be mounted in sealed sleeves and projected onto a screen. Color slide film produces brighter, more vibrant images than can be produced with color print film. (Black and white slide film exists, but is less common.)
Color slide film produced brighter, more vibrant images than color print film
The downside to slide film is that it’s more difficult to work with. Slide film has very little exposure latitude, meaning the exposure must be spot on to get a good image. Getting positive results (pun intended) requires a camera with proper exposure controls, as opposed to an inexpensive fixed-exposure camera, and a photographer who understands how to meter a scene properly. You have to know what you’re doing to shoot slides, which is why it was (and still is) regarded as a ‘professional’ film.
|Climbers approach the alpenglow-illuminated summit of California’s Mt. Shasta. (Kodak Ektachrome 100VS)
Photo: Dale Baskin
An Oversimplified Explanation of Color Slide Film Works
Color slide film works much like color print film, with layers of emulsions, each sensitive to a different color of light, and chemicals called dye couplers. When the film is developed, the interaction of the emulsion and the developer produces a positive image, which is (usually) cut and mounted in plastic or cardboard sleeves which can be fit into a carrier for a slide projector.
All slide film sold today uses the E-6 process. Kodak Kodachrome, a predecessor to E-6 slide film, used a different process (K-14) in which the color dyes were introduced during the development process. Kodachrome was discontinued in 2009 and the last Kodachrome processor shut down in 2010.
Types of Color Slide Film
|Photo: Dale Baskin
Because slide film cannot be color-corrected in processing, the film must be balanced for the type of light you are shooting. Today, most slide film is daylight balanced, and it reproduces incandescent lights as a reddish-brown. In the past, it was possible to buy tungsten-balanced slide film (which rendered incandescent lights properly but showed daylight as pale blue), but tungsten slide film is not (currently) available. For indoor, tungsten-lit photography with slide film, you can either use a 85A cooling filter or use a flash.
Because slide film cannot be color-corrected in processing, the film must be balanced for the type of light you are shooting
Among daylight films, there are notable variations in color rendition. Kodakchrome (now discontinued) was known for its warm reds and yellows, while Ektachrome emphasizes colder blue and green tones. Fujichrome Velvia makes colors pop – especially blues and greens, which made it a favorite of landscape photographers.
As with other types of film, the speed of slide film is specified as an ISO (a.k.a. ASA) number. Higher ISO film is more sensitive to light and therefore requires less exposure (smaller aperture or a quicker shutter speed). Color slide film is generally found in 50 to 400 ISO ranges, and the exposure required mimics that of our digital cameras: ISO 50 or 100 film requires a sunny day, while 400 speed film is better suited to cloudy conditions. Film can be ‘pushed’ to a higher speed (if your processing lab will agree to develop it accordingly), but this will generally increase grain.
|This candlelight vigil in New York City’s Union Square Park followed the 9/11 attacks on the World Trade Center, and is featured in the book Flags Across America. (Fujichrome Provia 100F)
Photo: Dale Baskin
How Much Does Color Slide Film Cost?
Slide film is the most expensive of all film types. 35mm slide film typically ranges from $15 to $20 per 36-exposure roll. 120-size slide film for medium-format cameras is usually sold in five-roll packs priced in the $45 to $55 range, but many vendors will sell individual rolls for $10-$12.
Developing Color Slide Film
Just as it is pricier than color print film to buy, color slide film is often (but not always) slightly more expensive to process. Conversely, with slide film you don’t have to worry about the cost of prints. Most labs will cut and mount your slides in cardboard or plastic unless you tell them not to. Slide scanning services are also available.
The downside to slide film is that it’s more difficult to work with. Slide film has very little exposure latitude, meaning the exposure must be spot on to get a good image
Like color negative film, color slide film can be developed at home using an E-6 processing kit. Compared to the C-41 color print process, E-6 has more steps and therefore more chemicals. Like C-41 (and unlike B&W developing), E-6 is very sensitive to time and temperature, and getting either one wrong (even slightly) can result in undesirable color shifts. The extra chemicals make E-6 kits more expensive, and while home developing is still cheaper than lab developing, the price difference is narrower than with other types of film.
It used to be possible to make photographic prints from slides using a process called Cibachrome (later known as Ilfochrome), but the supplies are no longer available. Color slide film can be scanned, but it looks best when projected. If you’re scanning, you may as well save money by shooting print film, unless you’re really after the ‘look’ of a particular slide film stock.
|Training climbers to extricate themselves from a glacial crevasse on Mt. Rainier’s Nisqually glacier. (Fujichrome Provia 400F)
Photo: Dale Baskin
Our ‘Absolute beginner’s guide to film photography’ is an educational series of articles focused on demystifying the ins and outs of analog photography. Geared toward those discovering (or re-discovering) film, the series will cover everything from gear, to technique and more. View all of the articles in our guide here.