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Working with Digital Media: Photoshop

Tips for working with audio and video, including how to use editing software and hardware available in the library.

Image modes

RGB Mode

  • three channels (Red, Green, and Blue)
  • used by all monitors and on the web 
  • recommended by adobe for editing color images


  • four channels (Cyan, Magenta, Yellow, Black)
  • used by professional printing houses.
  • if you are producing a images for a publication or poster, you may need to save it in CMYK mode

File formats and uses


  • preservation use
  • large file size 
  • no compression 
  • can embed layers


  • Photshop working file
  • keeps all layers and effects 
  • large file size


  • small file size
  • adjustable compression 
  • web and email friendly 
  • widely supported 
  • best for exporting with gradient 
  • no transparency (use gif or png) 

Printing and publication

  • Ask publisher for specific resolution and file format (TIFF is common)
  • Generally 300 PPI (pixels per inch) is used for print 
  • Print for a specific document size 

Save for web and devices

  • GIF, PNG, JPG are common formats
  • 72 PPI is standard resolution (speed is the goal) 
  • In Photoshop use “Save for web” under the File menu

Save for PowerPoint/Keynote

  • For image projection - you are limited to the maximum resolution of your projector. 
  • 1024 pixels wide is a good size (any bigger is unnecessary and slows your presentation due to larger file size)
  • Resize images in Photoshop to be the exact pixel dimension

Photoshop interface

Changing the resolution

Digital images are made up of pixels (pictures elements, one pixel=one color).  Pixel dimension describes the number of pixels in the image (width by height).  To change the resolution of an image, go to Photoshop menu --> select Image --> select Image Size.