DIS Print Production & Prepress 2 — Questions and Answers
Question 1: What is the purpose of 'color separation' in four-color offset printing?
- Dividing a full-color image into individual CMYK channels so each can be imaged to a separate plate (Correct answer)
- Separating an image into RGB components for accurate monitor display
- Isolating spot Pantone colors from process colors in a design file
- Converting Pantone swatch values to web-safe hexadecimal equivalents
Correct answer: Dividing a full-color image into individual CMYK channels so each can be imaged to a separate plate
Color separation produces four single-channel files—cyan, magenta, yellow, and black—each of which is used to expose a corresponding printing plate on a four-color press.
Question 2: What does GCR (Gray Component Replacement) accomplish in prepress color preparation?
- Replacing equal CMY components that form neutral tones with black ink to reduce total ink coverage (Correct answer)
- A method of boosting gray tones in scanned photographic images
- Converting RGB neutral gray values to named spot colors
- Adjusting gamma curves in black-and-white image files
Correct answer: Replacing equal CMY components that form neutral tones with black ink to reduce total ink coverage
GCR substitutes the equal amounts of cyan, magenta, and yellow that combine to make neutral grays with black ink, lowering total ink coverage, improving press stability, and reducing ink cost.
Question 3: What is the function of registration marks printed outside the trim area on press sheets?
- Providing alignment targets so press operators can register all color plates to the same position (Correct answer)
- Indicating the output resolution (DPI) specified for the job
- Defining the final trim and cut lines for bindery equipment
- Identifying which Pantone spot colors are specified in the print job
Correct answer: Providing alignment targets so press operators can register all color plates to the same position
Registration marks appear identically on every color separation and allow operators to visually and mechanically align plates so all inks print in exact register.
Question 4: What is 'imposition' in a prepress and print production workflow?
- Arranging multiple document pages on a press sheet so they read correctly after folding, cutting, and binding (Correct answer)
- Setting the output resolution and line screen frequency for a plate imager
- Adding bleed, slug, and crop mark areas to individual document pages
- Converting a document from RGB to CMYK color space before output
Correct answer: Arranging multiple document pages on a press sheet so they read correctly after folding, cutting, and binding
Imposition layouts arrange pages on a press sheet in the correct sequence and orientation so that after folding and trimming the bound signatures, pages fall in the right order.
Question 5: How does stochastic (FM) screening differ from conventional AM halftone screening?
- FM screening uses randomly placed dots of uniform size; AM screening uses regularly spaced dots of varying size (Correct answer)
- FM screening uses larger dots at higher frequencies than traditional AM screening
- FM screening arranges dots in circular patterns instead of angled line screens
- FM screening uses square dots while AM screening uses elliptical dots
Correct answer: FM screening uses randomly placed dots of uniform size; AM screening uses regularly spaced dots of varying size
FM (frequency modulated) stochastic screening varies the placement of same-size dots randomly, eliminating moiré patterns and producing smoother gradients compared to AM screening.
Question 6: What is the purpose of 'soft proofing' in a digital color-managed workflow?
- Simulating on a calibrated display how a document will appear when printed using a specific output ICC profile (Correct answer)
- Generating a low-resolution screen preview for remote client approval
- Printing a draft copy on plain office paper to check layout before final output
- Converting color images to grayscale to preview a black-and-white print version
Correct answer: Simulating on a calibrated display how a document will appear when printed using a specific output ICC profile
Soft proofing uses ICC output profiles to render a device-accurate color simulation on a calibrated monitor, allowing color verification without the cost of printing a physical proof.
Question 7: What does UCR (Under Color Removal) specifically target in CMYK image preparation?
- Removing CMY ink in neutral shadow areas and replacing it with black to reduce total ink density (Correct answer)
- Eliminating colors that fall outside the printable gamut of the output device
- Stripping under-saturated colors from color proofs before client presentation
- Deleting unused color channels from layered image files to reduce file size
Correct answer: Removing CMY ink in neutral shadow areas and replacing it with black to reduce total ink density
UCR selectively removes cyan, magenta, and yellow from the darkest neutral areas of an image and substitutes black ink, reducing ink pile-up and improving drying in shadow regions.
DIS Print Production & Prepress 2
What is the purpose of 'color separation' in four-color offset printing?