Computer to film (CTF) is a print workflow involving printing from a
computer straight to
film through an imagesetter. Designs are typically created in
Adobe Illustrator or
CorelDRAW, however they can also be produced in
AutoCAD
AutoCAD is a commercial computer-aided design (CAD) and drafting software application. Developed and marketed by Autodesk, AutoCAD was first released in December 1982 as a desktop app running on microcomputers with internal graphics controllers. ...
,
Inkscape
Inkscape is a free and open-source vector graphics editor used to create vector images, primarily in Scalable Vector Graphics (SVG) format. Other formats can be imported and exported.
Inkscape can render primitive vector shapes (e.g. re ...
and many other vector based
CAD,
design
A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process or the result of that plan or specification in the form of a prototype, product, or process. The verb ''to design'' ...
and
desktop publishing software packages. An imagesetter is an ultra-high resolution large-format computer output device for CTF.
For multi-coloured printing, the image is broken up into multiple layers representing each of the
spot colors or the
CMYK process colors, this may be split manually by the designer or separated by software in the imagesetter itself. Each color is made into its own piece of film and plate. There can be 12 or more colors used in a single production run; however, 1-6 colors are typical.
From the imagesetter, the film is taken to the plate maker, where the film is laid on top of
photopolymer plate
A photopolymer or light-activated resin is a polymer that changes its properties when exposed to light, often in the ultraviolet or visible region of the electromagnetic spectrum. These changes are often manifested structurally, for example hardeni ...
material. A vacuum is then drawn to ensure tight contact between the plate and film, the plate is then exposed with
UV Light. The plate is then washed in a solvent solution, typically water, where the unexposed areas wash away leaving a
relief
Relief is a sculptural method in which the sculpted pieces are bonded to a solid background of the same material. The term '' relief'' is from the Latin verb ''relevo'', to raise. To create a sculpture in relief is to give the impression that th ...
. It's then dried and given a second and final exposure without the film for durability. The plate can then be fitted onto an
offset,
rotary or
flexographic printing press ready to print the product. A printing plate can produce 100,000 impressions or more before showing signs of wear, after which a new plate can be made from the original film.
With advances in the technology of heat stabilization of
polyester film, new-generation
laser printer
Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics (and moderate-quality photographs) by repeatedly passing a laser beam back and forth over a negatively-charged cylinder called a "drum" t ...
films provide excellent
image registration and sharpness for multi-colour jobs.
Computer to film is being replaced by the more advanced
computer to plate (CTP) technology.
Printing terminology
Print production
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