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Graphics

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Graphics

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  1. Graphics Mrs. Bradley, Granbury High School

  2. Resolution • The number of pixels used to create an image. • Higher res. = more pixels, smaller pixels • Add detail & sharpen the image • More pixels = increased file size Mrs. Bradley, Granbury High School

  3. Resolution Measurement • Ppi (pixels per inch)—monitors • Width X Height • Display 72 PPI (Macs), 96 (Windows) • 72 PPI is accepted as standard • Images solely for viewing on screen only need to be 72 PPI. More pixels than needed—wasteful & unnecessary file size. • Dpi (dots per inch)—printers • Varies depending on printer. • 300 DPI is acceptable print standard • Printed 72 DPI, low quality Mrs. Bradley, Granbury High School

  4. 1 Resizing when the resolution doesn’t change 4 PPI/DPI 16 dots 1” x 1” 2” x 2” 4” x 4” Pixels are spaced out so they appear pixelated. The smaller the image, the higher DPI. The larger the image, the lower the DPI. Mrs. Bradley, Granbury High School

  5. Resizing w/ Res. Changes • Smaller—some pixels are deleted • Larger—some pixels added • New pixels: color is determined by colors of its neighboring pixels. The computer guesses. • Enlargements—too large, detail is lost b/c of too many new pixels. • Extra large—image will appear pixelated. Mrs. Bradley, Granbury High School

  6. Why understand resolution? • Higher res. slows down loading time for Web pages. • Lower res. for print looks blurry or pixelated. Mrs. Bradley, Granbury High School

  7. Compression • Lossy • Lossless Mrs. Bradley, Granbury High School

  8. Lossless • No loss • Compresses the file w/o losing any quality. • No degradation • Packs—unpacks—everything is there Mrs. Bradley, Granbury High School

  9. Lossy • Rhymes with bossy • Degrades when compressed (packed) • Each time the file is compressed and then reopened a portion is lost. • Some files allow you to control compression (jpegs) • Lower compression = higher quality = large • Higher compression = lower quality = smaller files Mrs. Bradley, Granbury High School

  10. Example Mrs. Bradley, Granbury High School

  11. Why compress? • Saves file space when needed Mrs. Bradley, Granbury High School

  12. Vector Graphics • Professional publishing standard • Mathematical formulas, lines, angles • Enlarged w/o losing quality • Business cards—banners—billboards • Corel Draw, PowerPoint drawings • Adobe Illustrator, MS Clipart .wmf Mrs. Bradley, Granbury High School

  13. Raster Graphics • Made up of pixels • Referred to sometimes as bitmaps • Do not resize well • Pixels become obvious when enlarged • MS Paint Mrs. Bradley, Granbury High School

  14. Bitmap Image Mrs. Bradley, Granbury High School

  15. jpeg • Photos • Images with many colors • Lossy (adjustable) • Photos for the Web Mrs. Bradley, Granbury High School

  16. gif • Simple-colored logos, text, images • 256 colors or less • Used for the Web • Supports animation • Not good for photos—discards colors based on similar color patterns • Transparent background capabilities • Universal format Mrs. Bradley, Granbury High School

  17. png • “New and improved” gif • More then 256 colors • Smaller file sizes than gifs • Lossless • Not always supported by all web browsers Mrs. Bradley, Granbury High School

  18. tiff • Highest quality lossless file type • File size is much larger than jpegs • Universal format • Professional publishing preferred Mrs. Bradley, Granbury High School

  19. bmp • Last resort • No compression • Large files • Do not resize well • pixelated • MS Paint Mrs. Bradley, Granbury High School