science

Roll film

Roll film is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Roll film rather than just read about it. In short: Roll film or rollfilm is any type of spool-wound photographic film protected from white light exposure by a paper backing. The term originated in contrast to sheet film.

Key takeaways

Roll film belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Roll film to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Roll film from memory before moving on to harder problems.

Reference excerpt

Roll film or rollfilm is any type of spool-wound photographic film protected from white light exposure by a paper backing. The term originated in contrast to sheet film. Roll film was originally often referred to as "cartridge" film because of its resemblance to a shotgun cartridge. The opaque backing paper allows roll film to be loaded in daylight. It is typically printed with frame number markings that can be viewed through a small red window at the rear of the camera. A spool of roll film is usually loaded on one side of the camera and pulled across to an identical take-up spool on the other side of the shutter as exposures are made. When the roll is fully exposed, the take-up spool is removed for processing and the empty spool on which the film was originally wound is moved to the other side, becoming the take-up spool for the next roll of film.

History

In 1881, a farmer in Cambria, Wisconsin, Peter Houston, invented the first roll film camera. His younger brother, David, filed the patents for various components of Peter's camera. David Henderson Houston (born June 14, 1841; died May 6, 1906), originally from Cambria, Wisconsin, patented the first holders for flexible roll film. Houston moved to Hunter in Dakota Territory in 1880. He was issued an 1881 patent for a roll film holder that he licensed to George Eastman and was used in Eastman's Kodak 1888 box camera. Houston sold the patent and an 1886 revision outright to Eastman for $5000 in 1889. Houston continued developing the camera, creating 21 patents for cameras or camera parts between 1881 and 1902. In 1912, his estate transferred the remainder of his patents to Eastman.

The most popular roll film format is 120 film, which is used in most medium format cameras and roll film magazines for large-format cameras. Until the 1950s, 120 roll film was, with the smaller 127 film, also used in the simplest of box cameras and other snapshot cameras. The use of roll film in consumer cameras was largely superseded by 135 and 126 cartridges, but 120 and 220 (double length) film are still commonly used in medium format cameras.

Automatic film speed sensing In 1998, Fujifilm introduced a film identification system for 120 and 220 format roll film called Barcode System (with logo "|||B"). The barcode encoding the film format and length as well as the film speed and type is located on the sticker between the emulsion carrying film and the backing paper. This 13-bit barcode is optically scanned by newer medium format cameras like the Fujifilm GA645i Professional, GA645Wi Professional, GA645Zi Professional, GX645AF Professional, GX680III Professional and GX680IIIS Professional, the Hasselblad H1, H2, H2F and H3D Model I with HM 16-32, and the Contax 645 AF.

See also Film stock Brownie (camera) Film format List of color film systems List of film formats

References

Illustrations

A spool of Fujifilm-brand type 120 negative roll film

Worked examples

Example 1 — a first encounter with Roll film

Start with the simplest possible case. Write down what Roll film claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Roll film before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Roll film ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Roll film

In research: Roll film appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Roll film in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Roll film is common in secondary-school and first-year university syllabi. It links to neighbouring topics Film formats, Photography equipment, so understanding it makes those chapters shorter.
In everyday life: Look for Roll film outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Roll film in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Roll film means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Roll film out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Roll film in simple terms?

Roll film or rollfilm is any type of spool-wound photographic film protected from white light exposure by a paper backing. The term originated in contrast to sheet film.

Why does Roll film matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Roll film?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Roll film.