Raster image vs Vector
Raster images are a format that converts a range of computational data into a pixel based graphic. These are typically your physical graphic images. A vector image on the other hand is a math and geometric based rendering, using points, lines, and polygons. These are used in conjunction with engineering, with CNC machines, and 3D printers.
Resolutions required for digital and print media
Most printers have a resolution between 600-1200 dpi, but digital resolution can be as low as 72 pixels per inch to fill a screen.
CMYK vs RGB
CMYK is a subtractive color system that uses the colors, cyan, magenta, yellow and black. I don’t understand how they came to conclusion that “K” should represent black, but here we are. This is used primarily for prints. RGB on the other hand an additive color system, using the primary colors of red, green, and blue are added together. These colors are used for digital media outlets.
Pantone Colors
Pantone Colors are another color system, that uses spot ink. These are important in graphic design, because they are replicated in both digital and print almost perfectly.
Process vs spot color
Spot colors are colors that must be mixed and applied independently, and are intended to applied one at a time, through different printing units. The Pantone library was created to mix pigments for spot colors. Whereas, Process colors are of the CMYK variety. They're typically transparent and most devices can only image with four process colors.
Preflight analysis for print and web
Preflight is the task of checking a computer graphic document in preparation for the manufacturing process.
Font Management / Adobe type 1 fonts with TrueType
Adobe Type 1 is a font type (obviously) developed by Adobe. It’s a vector-based Post Script font, that produces high resolution and resizable graphics, due to the vectorized rendering. TrueType is a font type developed by Apple. They’re easy to install, and contain both print and screen font data. There are some issues with rendering between the two, when a font from Adobe Type 1 and TrueType share a font ID number. The RIP will use the same matrix for both fonts, effectively distorting the spacing, page breaks, and other formatting.
Transparency / Communicate intent to printer
Transparency in graphic design production can also have issues. The RIP can throw away raster data that is covered by a transparent element, which will not result in WYSIWYG. If elements show through the foreground by more than 20%, it will hold much more data, which may not process in the final print if too taxing on the system. Designer will usually solve this by creating layers that can be adjusted with ease.
Describe six pre-imaging file analysis processes that should be considered when developing a computer graphic for reproduction manufacture.
1.Raster image processing (RIP) technologies
Core technology that does the computational work to convert the broad range of data we use to create a computer graphic into the one-bit data that drives a physical imaging device. Has a matrix grid at the resolution of the output device and computes which spots on the grid get turned on and off (binary code)
2. Color Management
RGB – for digital design, varied depending on the computer
CMYK – color for print, process color ink
Process color – printer mixes the (usually four) colors using the CMYK ink
Spot color – opaque inks, applied one at a time
Pantone – spot color library that is considered the standard in North America. When using pantone colors, you are more likely to get a print out of exactly what you see on the computer screen.
3. Trapping to lithographic and flexographic specifications
Trapping is an electronic file treatment that must be performed to help solve registration issues on certain kinds of press technologies, A technique of printing one ink on top of another one. Poor trapping makes ink not adhere properly, such as forming little beads or ink that rubs off too easily (i.e. receipt paper). Lithographic: generating trap line to a standard for lithography of three one-thousandths of an inch, allows misregistration to happen without being noticeable. Flexographic: trapping can be done automatically with software, or should be left to a specialist, as this is the most difficult printing process used for printing on things other than paper.
4. Transparency
Printed form may cut out background details, may not resemble digital image. Transparency is taxing on the computational data of a RIP. PostScript – 3D language allowing you to stack and prioritize elements on a page. More raster data is required for transparency bc computer usually knocks out covered elements. Many times data is lost if there are not enough addresses available for the computations
Solutions:
-Use layers well when creating documents
-Allowing the page layout software to raster the page elements, so it sends raster data to the RIP, you can choose the resolution of the elements
-Ensure overlapping elements raster at the same resolution
5. Imposition for pre RIP and post RIP for media utilization
Imposition (the arrangement of he printed docs pages on the printer’s sheet), serves 2 purposes: It can utilize media and manufacturing equipment with the most economic efficiencies, and add furniture to the manufactured sheet to control processes. The simplest type of imposition is duplexing. It can be specified through multiple mediums, such as PDF, the print driver and RIP. Sheet wise impositions are image the fronts of all pages on one side of the sheet, backs on a separate set of plates for a press run that will back up all the sheets.
6. Preflight analysis and automation for computer file creation
Preflight is the task of checking a computer graphic document in preparation for the manufacturing process. Software can be purchased to preflight and generate reports about a PDF of PostScript file. Preflight is typically used for: File format, color management, fonts. spot color, handling page structure, thin lines, black overprint, and trapping.
Describe four major imaging technologies that utilize computer graphics to image on different substrates.
Electrophotography (typical printer)
-Uses process colors
-All colors are put on the drum one at a time, but then all applied to the substrate at once
-Doesn’t misregister
Inkjet
-All heads are mounted on the same unit travelling the same track
-Rarely misregisters
-Any issues can typically be adjusted
-No trapping necessary
Flexography
-Trapping necessary
-Separate printing plate for each color
Lithography
-Separate printing plates for each color for spot ink
-Can cause registration errors
-Has issues with gradient
How many addressable values can be recorded in an eight-bit byte of computer data?
256 glyphs
What does the acronym WYSIWYG stand for?
What You See Is What You Get
How many kerning pairs are present in a ‘good’ font file?
600-800 kerning pairs
What colour matching library has been developed exclusively for process colour printing inks (CMYK)?
Pantone
What two printing processes must have trapping applied to computer graphics files before making printing plates?
Lithography and Flexography
What can a page layout artist do to a graphics file if the transparent elements on the page are dropping out or not processing in the RIP?
A page layout artist can work in easily adjustable layers, or rasterize the graphic elements.
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