computer science

IT8

IT8 is a computer 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 IT8 rather than just read about it. In short: IT8 is a set of American National Standards Institute (ANSI) standards for color communications and control specifications. Formerly governed by the IT8 Committee, IT8 activities were merged with those of the Committee for Graphics Arts Technologies Standards (CGATS Archived November 9, 2018, at the Wayback Machine) in 1994.

Key takeaways

IT8 belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect IT8 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IT8 from memory before moving on to harder problems.

Reference excerpt

IT8 is a set of American National Standards Institute (ANSI) standards for color communications and control specifications. Formerly governed by the IT8 Committee, IT8 activities were merged with those of the Committee for Graphics Arts Technologies Standards (CGATS Archived November 9, 2018, at the Wayback Machine) in 1994.

Standards list The following is a list of the IT8 standards, according to the NPES Standards Blue Book Archived July 19, 2011, at the Wayback Machine:

IT8.6 - 2002 - Graphic technology - Prepress digital data exchange - Diecutting data (DDES3) This standard establishes a data exchange format to enable transfer of numerical control information between diecutting systems and electronic prepress systems. The information will typically consist of numerical control information used in the manufacture of dies. 37 pp.

IT8.7/1 - 1993 (R2003) - Graphic technology - Color transmission target for input scanner calibration This standard defines an input test target that will allow any color input scanner to be calibrated with any film dye set used to create the target. It is intended to address the color transparency products that are generally used for input to the preparatory process for printing and publishing. This standard defines the layout and colorimetric values of a target that can be manufactured on any positive color transparency film and that is intended for use in the calibration of a photographic film/scanner combination. 32 pp.

IT8.7/2 - 1993 (R2003) Graphic technology - Color reflection target for input scanner calibration This standard defines an input test target that will allow any color input scanner to be calibrated with any film dye set used to create the target. It is intended to address the color photographic paper products that are generally used for input to the preparatory process for printing and publishing. It defines the layout and colorimetric values of the target that can be manufactured on any color photographic paper and is intended for use in the calibration of a photographic paper/scanner combination. 29 pp.

IT8.7/3 - 1993 (R2003) Graphic technology - Input data for characterization of 4-color process printing The purpose of this standard is to specify an input data file, a measurement procedure and an output data format to characterize any four-color printing process. The output data (characterization) file should be transferred with any four-color (cyan, magenta, yellow and black) halftone image files to enable a color transformation to be undertaken when required. 29 pp.

Targets

Calibrating all devices involved in the process chain (original, scanner/digital camera, monitor/printer) is required for an authentic color reproduction, because their actual color spaces differ device-specifically from the reference color spaces. An IT8 calibration is done with what are called IT8 targets, which are defined by the IT8 standards.

Example Special targets, implementing the IT8.7/1 (transparent target) or IT8.7/2 (reflective target) standards, are needed for calibrating scanners. These targets consists of 24 grey fields and 264 color fields in 22 columns:

Column 01 to 12: HCL color model, which differ in Hue, Chroma, and Lightness Column 13 to 16: CMYK-Colors Cyan, Magenta, Yellow, and Key (black) in different steps of brightness Column 17 to 19: RGB-Colors Red, Green, and Blue in different steps of brightness Column 20 to 22: undefined, producers' choice After scanning such a target, an ICC profile gets calculated on the basis of reference values. This profile is used for all subsequent scans and assures color fidelity.

See also List of colors Color chart Color calibration Color management Color mapping ICC profile

References Romano, Richard and Frank. (1998). The GATF encyclopedia of graphic communications. GATF Press. Digital Color Imaging Handbook; Gaurav Sharma; ISBN 978-0-8493-0900-7; 2002.

Worked examples

Example 1 — a first encounter with IT8

Start with the simplest possible case. Write down what IT8 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer 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 IT8 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 IT8 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 IT8

In research: IT8 appears in computer 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 IT8 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: IT8 is common in secondary-school and first-year university syllabi. It links to neighbouring topics American National Standards Institute standards, Computer graphics, Print production, so understanding it makes those chapters shorter.
In everyday life: Look for IT8 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 IT8 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IT8 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 IT8 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IT8 in simple terms?

Why does IT8 matter?

Because it connects several computer 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 IT8?

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 IT8.

IT8