Film to PhotosFilm scanning glossary: the words explained simply
Plain-English meanings of the words you meet when scanning film negatives: DPI, orange mask, film base, emulsion side, C-41, 16-bit TIFF, iSRD and ICE, Newton rings and more.
This glossary explains, in plain words, the terms you'll meet when you turn film negatives into digital photos. You don't need to know any of them to use Film to Photos, but they help when you read guides or forums.
Film
Color negative
The most common film for family photos. Colors and brightness are reversed and the whole strip looks orange. It has to be converted to look like a normal photo. See how to tell what film you have.
Slide
Also called transparency or reversal film. Already a positive picture, usually in a small square cardboard or plastic mount. Film to Photos doesn't support slides yet.
Black-and-white negative
A negative in shades of gray with no orange color. Film to Photos recognizes black-and-white film automatically (new, still being tested on more film).
C-41
The standard developing process for color negative film. If the film box or envelope says C-41, it's a color negative.
35 mm
The most common film size, with frames of 36 × 24 mm. Plustek OpticFilm scanners take 35 mm film only.
120 film
Medium format film, wider than 35 mm. It needs a flatbed with a film adapter or a medium-format scanner.
Frame
One picture on the film strip. A roll usually has 24 or 36 frames.
Film base
The clear (orange, on color negatives) plastic the image sits on. The gaps between frames show pure film base, which conversion software measures.
Orange mask
The orange tint built into color negative film so prints come out with clean colors. It has to be removed when converting. See how to remove the orange mask.
Emulsion side
The side of the film with the light-sensitive coating that holds the picture. It usually looks duller than the shiny base side. The film holder shows which way it should face; if a photo comes out mirrored, flip it in software.
Scanning
DPI
Dots per inch: how many pixels the scanner records per inch of film. 3600 dpi gives about 17 megapixels from a 35 mm frame; 1800 dpi about 4 megapixels. See what DPI to scan 35 mm film at.
Megapixel
One million pixels. A rough measure of how big a photo can be printed: about 17 megapixels prints well at 8×10 inches and beyond.
Film scanner
A scanner made for film, with a light that shines through the negative. Plustek OpticFilm models are common examples.
Flatbed scanner with film adapter
A photo scanner with a light in the lid, so it can scan film as well as prints. A normal document scanner can't scan negatives.
Film holder
The plastic frame that keeps film flat while scanning. Plustek negative holders take a strip of up to six frames.
Infrared dust removal (ICE, iSRD, Infrared Clean)
Some scanners (Plustek models with an "i" in the name) take an extra infrared scan that sees dust and scratches but not the picture, so software can remove them. Called iSRD in SilverFast, Digital ICE in other scanners and Infrared Clean in VueScan. Film to Photos doesn't use it yet. See dust on film scans.
Newton rings
Rainbow-colored rings that can appear where film touches glass. Keeping film in a glassless holder avoids them.
Driver
Software that lets a computer talk to a device. Many Plustek scanners have no current Mac driver; some apps, such as Film to Photos and VueScan, include their own. See Plustek OpticFilm Mac drivers.
SANE
"Scanner Access Now Easy", an open-source project that supports many scanners. Film to Photos' Scanner Helper is built from it.
Files
TIFF
A file type that keeps every detail (lossless). Best for archiving. A 16-bit TIFF holds even more tonal detail and is good for heavy editing. See TIFF or JPEG?
JPEG
The everyday photo file type: small, opens everywhere, loses a little detail each time it's saved. Best for sharing.
16-bit
Each color can have 65,536 levels instead of 256 (8-bit). It avoids banding when you edit faded film strongly.
HEIC
The photo file type iPhones use by default. Film to Photos can import iPhone HEIC photos of negatives.
Camera RAW
The unprocessed file a camera can save (CR3, NEF, ARW and similar). Film to Photos doesn't import camera RAW yet; export to TIFF first.
Color
White balance
Making whites and grays look neutral, without a blue or orange tint.
Color cast
An unwanted tint over the whole photo, such as pink walls or blue skies that are too blue. See why scanned negatives look purple.
Curves
A tool for fine control of brightness and contrast, from dark to light. Film to Photos' editor has curves for people who want them.
Fading
Old color film and prints lose their dyes over time and drift toward red or magenta. Scanning the negative usually recovers more than scanning the print. See how to fix faded scans.
Quick answers
What does DPI mean when scanning film?
Dots per inch: how many pixels the scanner records for each inch of film. A 35 mm frame scanned at 3600 dpi is about 5100 × 3400 pixels, roughly 17 megapixels.
What is the emulsion side of a negative?
The side with the light-sensitive coating. It usually looks duller than the shiny base side. Film holders show which way it should face.
What is C-41?
The standard chemical process for color negative film. Almost all color negatives from family photos are C-41 film.