of Pixels and Bits


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Photo Communications, Spring 2012
Columbia College Chicago

Published in: Design

of Pixels and Bits

  1. 1. 22-3530 - 01 PHOTO COMMUNICATIONS of pixels and bits
  2. 2. Measuring pixels
  3. 3. VECTOR IMAGESBased on points & paths, numerical Resolution independent
  4. 4. RASTER IMAGES (bitmap)A mosaic of pixels (picture elements) Resolution dependent
  5. 5. 1132 pixels 1430 pixels Raster = Resolution Dependent Each raster image is made of a speci c number of pixels (pixel dimensions)
  6. 6. IMAGE DETAILEvery time you capture a digital image, you create a speci cnumber of pixels. Image detail is translated into differences between pixels that the camera registers at the time ofcapture. Increasing resolution degrades the true detail from the capture with a ‘best guess’ (interpolation).
  7. 7. VIEW PERCENTAGE1430 x 1132 1024 x 768
  8. 8. View percentage at 100%
  9. 9. View percentage at 60%
  10. 10. BIT DEPTH Every raster image contains a certain number of pixels.Every pixel contains a certain number of bits (ones or zeroes). The number of bits contained in each pixel is called the image’s bit depth. for example, If you are working with an 8-bit grayscale image, each pixel contains 8 zeroes or ones. 2 = 01010101 = 256 8
  11. 11. 8 BIT vs (12 vs) 16 BIT
  12. 12. BIT DEPTH AND FILE SIZE File size is directly connected to the number of bits contained in an image. For example, 8 bits = a byteIf an 8-bit grayscale image has a pixel dimension of: 1430 x 1132 = 1618760 pixels 1618760 divided by 1024 (a kilobyte) = 1580.82 1580 divided by 1024 (a megabyte) = 1.54 1 kilobyte = 1024 bytes 1 megabyte = 1024 kilobytes
  13. 13. IMAGE SIZE WINDOWThree different ways of describingimage size:1. Image size2. Pixel dimensions (count)3. Document size: how the pixels are distributed in the “real world,” i.e., your printer
  14. 14. Tone
  15. 15. LEVELSHi-contrast Lo-contrast
  17. 17. TONAL KEYTonal character can be de ned in terms of light, dark, or average, or use the terms high, low, and medium key.high key medium key low key
  18. 18. DESTRUCTIVE EDITS All tonal edits “damage” the le to some extent. Extreme edits to tone using levels or curves can leave large tonal ranges completelyempty. These gaps in the histogram create what is called banding or posterization.
  19. 19. NON-DESTRUCTIVE EDITSUsing adjustment layersallows you to make tonaladjustments withoutpermanently deletingcapture data.
  20. 20. SHADOW AND HIGHLIGHTBe sure to always keep an eye on maintaining shadow and highlight detail when making tonal edits.
  21. 21. for lm: Expose for the shadows and develop for highlights for digital: Expose for highlights (most of the time)
  24. 24. CURVESCurves allows you to focus your corrections more accurately within the histogram than Levels.
  27. 27. Pixel quality control
  28. 28. SHOOTING ASSIGNMENT #2Finding design patterns
  29. 29. LineShapeTextureSpace SizeValue
  30. 30. LINELines can organize, direct,separate, be expressive,suggest emotion, or createrhythm. They can joinelements or divide themusing a rule, which is a linethat separates one elementin a design from another.
  31. 31. SHAPEThe external outline of aform or anything that hasheight and width.An example would be thethree basic shapes: thecircle, the square, and thetriangle, considered to bethe fundamental shapesfound in all design.
  32. 32. TEXTUREThe look and feel of a surface. In two-dimensional form, texture isessentially visual and adds richness and dimension to work. Texture canalso refer to pattern, which is visual texture.
  33. 33. SPACERefers to the distancebetween shapes and forms,but it is best understoodin design as white space ornegative space—termsused to refer to the emptybut often active areas thatare void of visual elements.
  34. 34. SIZEHow big or small something is inscale to other objects. Scale refersto the process of making sizerelationships. unless there is ascale of reference within a design,it is impossible to discern therelative scale of objects and themeaning they represent.
  35. 35. VALUE (& COLOR)The relative lightness ordarkness of an area or object.Value adds dimension bycreating the illusion of depthin a design. With the additionof a color, you can create andconvey a mood to enhance astrong concept.