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Published byPrudence Floyd Modified over 8 years ago
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ADOBE PHOTOSHOP VECTOR VS RASTER
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Pixel A pixel is the fundamental unit of an image in Photoshop. It is a small square block of color. An image often consists of many pixels arranged in rows and columns.
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Vector Image Is a mathematical defined line or curve. Vectors are used to define objects typified by line art. It can be arbitrarily scaled with out loosing detail. Illustrator images are examples of vector images.
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Raster Image A grid into which the pixels are arranged Images made up of pixels are referred to as raster images Raster images can not be enlarged without the pixels becoming visible
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RASTER VS VECTOR VECTOR CAN BE SCALED RASTER LOSES QUALITY IF SCALED
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Interpolation The mathematical process of estimating what comes between two things. Example: You are asked to pick a number between 2 and 4, you would probably choose 3 that is interpolation an ESTIMATE – by definition interpolation introduces inaccuracies.
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Interpolation
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Image Resolution measured in pixel per inch (ppi) Used to determine the actual number of pixels in an image expressed by width or height Example: a 4”X 5” image with an image resolution of 300 ppi will have pixel dimensions of 1200 X 1500 pixels. (4 x 300=1200 and 5 X300=1500)
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Resolution Designated by output Web (monitor) 72 Printing Laser printer 300 Ink jet 150 Commercial Printing line screen X 2 Newspaper -line screen 85 Brochure -line screen 150 High end printing up to line screen -2400
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Color mode Bitmap- black and white ( no grey) Grayscale- 256 shades of grey RGB monitor color (red green blue) CMYK printing (cyan magenta yellow black)printing
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Resampling The process of changing the pixel dimensions or number of pixels in an image Making an image larger or smaller or changing the resolution. Photoshop uses interpolation to determine the intermediate pixels to use
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Resampling Methods of interpolation Answer Bicubic smoother Bicubic sharper Bicubic Nearest neighbor Bilinear
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Resampling Methods of interpolation Answer Bicubic smoother (making images larger) Bicubic sharper (making images smaller) Bicubic (older) Nearest neighbor (older) Bilinear (older)
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Resampling Down making an image smaller or lowering the resolution Image | image size resampling off lower resolution resampling on constrain proportions on change the size bicubic sharper ok
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Photoshop document.PSD Working file - keeps all of its layers Keep this file if you need to make changes to your JPG or GIF Raw files are simple files that contain no extra data. This format doesn't allow any compression.
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Web formats JPG compressed for the web. It should be saved only once ( go back to your PSD files to make a change) it will continually compress. OK to open over and over but do not save more than once. You don't just lose image data the first time you save your file as a JPEG, but every time you save it thereafter your image is degraded. It's best if you keep your file set up as a Photoshop-native file (PSD) and then save it as a JPEG once you complete your work.
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Web formats GIF converts to 8 bits (256 colors or less). It will throw out any color not included in 256 colors. For that reason, you may want to save photographs to be used on the Web as JPEGs and use the GIF format when saving graphics that use a limited color palette.
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Print formats EPS Encapsulated Post Script it can not be touched or modified in a page layout program TIF Tagged Information format more flexible than EPS used in page layout programs
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Other Formats PNG works with Macromedia flash Supports transparency
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Review Question: PPI is an acronym which stands for
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Review Question: PPI is an acronym which stands for Answer Pixel per inch
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Review Question: What is the smallest visual unit a Photoshop picture can be broken down into?
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Review Question: What is the smallest visual unit a Photoshop picture can be broken down into? Answer Pixel
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Review Question: The process of estimation what comes between two things is called:
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Review Question: The process of estimation what comes between two things is called: Answer Interpolation
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Review Question: True or false if I change the resolution of a 150 ppi to 300 ppi and it becomes blurry, I can easily restore the crispness by changing it back to 150.
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Review Question: True or false if I change the resolution of a 150 ppi to 300 ppi and it becomes blurry, I can easily restore the crispness by changing it back to 150. Answer False
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Review Question : If I am scanning an image for the web what should the resolution be?
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Review Question : If I am scanning an image for the web what should the resolution be? Answer 72 ppi
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Review Question : Name two methods of interpolation
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Review Question : Name two methods of interpolation Answer Bicubic smoother Bicubic sharper Bicubic Nearest neighbor Bilinear
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Review Question : The most important thing in determining what the resolution of an image should be is
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Review Question : The most important thing in determining what the resolution of an image should be is Answer It’s final output device
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Review Question : How do you determine the resolution for printing?
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Review Question : How do you determine the resolution for printing? Answer Linescreen x 2
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Review Question : If you need to make an image larger which interpolation should you use?
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Review Question : If you need to make an image larger which interpolation should you use? Answer Bicubic smoother
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Review Question : If you need to make an image smaller which interpolation should you use?
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Review Question : If you need to make an image smaller which interpolation should you use? Answer Bicubic sharper
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Review Question : Name a vector based program
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Review Question : Name a vector based program Answer Adobe Illustrator Corel Draw Freehand
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Review Question : Name a raster based program
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Review Question : Name a raster based program Answer Adobe Photoshop Paint Adobe Elements
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