CARTOGRAPHY III

Lesson 5

By Mwaura Joshua | @openmapsCo on Twitter

Lesson 5: Map reproduction

Map Reproduction

• This refers to printing of a map, or the electronic duplication of a map
• Print reproduction refers to the physical printing of a map using inks on paper
• Electronic reproduction refers to the duplication of a map in digital form
• We will focus on print reproduction

Map Reproduction | Planning

• 1. Determine the number of maps to be reproduced
• Reproduction consideration; Printing methods to be used
• 2. Select a scale and map projection that is appropriate for the map’s theme
• This forms the foundation of your map
• Questions to be answered at this stage
• Who’s the intended audience, & what’s purpose of the map?
• What is your budget?
• When is your deadline?
• What material will be used?
• Will it be printed in full color or gray tones?

Map Reproduction | Editing

• The critical evaluation and correction of every aspect of a map
• This begins the first time the cartographer views the map in its early stages, and culminates just before printing
• Questions that should be addressed when editing
• Map design; Does the design appropriately serve the map user? Does it communicate effectively?
• Completeness; Are any features, map elements, or type labels missing?
• Accuracy; Are features, map elements, and type labels correctly placed? Are words and numbers correct?

Map Reproduction | Editing

• Cartographers who edit their own maps face over-familiarity and fatigue, thus, you need
• Have a separate individual edit the map
• Edit with fresh eyes, at the beginning of a work session
• Edit large maps in sections
• View maps upside-down or sideways
• Edit after several days of separation from a map
• Read type out loud

Print Reproduction | Screening

• Screening is a technique that makes colors appear lighter
• It involves reducing the amount of ink or toner applied to the print medium
• its used to create tints of a base color, and to represent continuous tone surfaces
• Two categories of screening
• Halftone
• Stochastic

Print Reproduction | Screening: Halftone

• Used in most print reproduction methods with the exception of ink-jet printing
• Ink or toner is applied in a pattern of equally spaced dots of variable size
• Helped define the pop art movement...

Print Reproduction | Screening: Stochastic

• Used primarily with ink-jet printing
• Ink or toner is applied in a pattern of very small, pseudo randomly spaced dots of uniform size

Print Reproduction | Aspects of Color Printing

• Process colors
• CMYK (subtractive primaries + black)
• Mixed on the page by applying them, in sequence, to the same area

Print Reproduction | Aspects of Color Printing

• Semi-opaque, or translucent, allowing them to combine on the page
• Together with screening, allow for the creation of a wide variety of colors
• Used in four-color process printing

Print Reproduction | Aspects of Color Printing

• When mixed on the page, tints of each base color are represented by halftone patterns, each with a unique screen angle

Print Reproduction | Aspects of Color Printing

• Spot colors
• Opaque inks that are premixed before they reach the printing device
• Tints can be created through screening
• Exact color matches are easier to achieve because they do not rely on the printing device for mixing

Print Reproduction | High Volume Print Reproduction

• When large numbers of maps are required, issues of cost and time become critical
• Methods for low-volume print reproduction such as laser and ink-jet printing become too costly or time-consuming
• High-volume reproduction is dominated by a single method:- Offset Lithography

Offset Lithography

• Lithography is a printing process in which ink sticks only to certain areas of a surface
• Virtually all mass-produced maps are the result of offset lithography
• Characterized by excellent print quality and high printing speed
• Provides a significant decrease in the cost per unit as the number of copies increases

Offset Lithography Process

• 1. Pre-press phase
• Consists of various technologies and procedures
• Printing plates and Proofs are produced
• 2. Printing plate
• A sheet of aluminium that is mounted on a roller on an offset press, receives a positive, latent (invisible) image that ink sticks to, one for each color

Offset Lithography Process

• Traditionally created from film negatives, are now replaced by Computer-To-Plate (CTP) technology

Offset Lithography Process

• Proof
• A representation of what the final, reproduced map will look like
• An essential component of the prepress phase, allows editing to ensure that your map will be reproduced just as you intend
• Various levels of quality/cost

High Volume Print Reproduction

• File formats for pre-press
• A digital map can be delivered to the printing house in a variety of formats
• In the native format of the application software that created it (.MXD, .AI)
• In a page description language (Postscript)
• In a portable document format (EPS, PDF)

Offset Lithographic Printing

• The offset press has one or more printing units that transfer ink to the print medium
• Each printing unit is capable of printing one base color

Offset Lithographic Printing

• The image is transferred from the printing plate to the blanket cylinder, which then transfers the image onto the print medium

Offset Lithographic Printing

• Multi-color print jobs employ multiple printing units, one for each base color
• The print medium receives a different color ink from each printing unit

--End of Lecture 5--

That’s it!

Queries about this lesson, please send them to: jmwaura.uni@gmail.com

***References***

• Mapping, Society, and Technology, Steven Manson
• Web Cartography, Map Design for Interactive and Mobile Devices, Ian Muehlenhaus
• Web Cartography, Menno-Jan Kraak and Allan Brown, ITC
• Cartography, Thematic Map Design, Borden D. Dent
• GIS Cartography, A Guide to Effective Map Design, Gretchen N. Peterson
• Thematic Cartography and Geovisualization, Terry A. Slocum et.al