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Scanning & Digital Images for Instructors

Whether you capture images on a scanner, use digital camera images, or create your own infographics, you'll want to optimize images to best suit how they'll be distributed—on a web page, in a presentation, or in video. Employing image files that are larger than necessary slows downloads. Employing images that are to small in pixel dimensions impairs image quality.

For help learning to resize images or convert image file types, contact the Instructional Media Lab (545-2823, instruct@umass.edu) or search for tutorials for your image editing software on Hoonuit (previously Atomic Learning).

Note: when scanning, we recommend capturing a large image file (at least 300 pixels per inch, 24 bit color). You can then resize a copy for each use (web page, presentation, video, print, etc.).

Web Page Guidelines

File type

  • For images that are mostly solid areas of color
        Save charts and infographics in the PNG format.*
  • For photographic images
        Save photos in the JPG format.  You'll need to compromise between download speed and image quality:
        •  Higher compression provides a smaller file size and faster downloads, but lower image quality
        •  Lower compression creates larger file size and longer download time, but better image quality.

Dimensions

  • If you are using an online service for your website such as Blogs at UMass or Drupal, follow the guidelines for the "theme" you are using to provide images with the best dimensions for different uses (logos, banner backgrounds, thumbnails or feature images).
  • If you are using Moodle or building a website from scratch, resize images to the dimensions they should appear on screen.
    Typical image dimensions
         •  Thumbnail: 180 x 180 pixels
         •  Large illustration: 480 pixels maximum dimension
         •  Full page images: 900 to 1500 pixels wide, depending on site layout.
    Tip: rather than filling your page with a large illustration, display a smaller version (thumbnail) and have it link to a larger version of the image.

Presentation Software Guidelines

For Google Slides, see https://support.google.com/docs/answer/97447?hl=en
For Prezi, see https://prezi.com/support/article/creating/inserting-images/

To prepare images for desktop presentation software such as PowerPoint or Keynote, follow these guidelines.

File type

  • For images that are mostly solid areas of color (charts and infographics), save the PNG format.
  • For photographic images, save in the JPG format.  You'll need to compromise between speed of download and image quality:
         • Higher compression provides a smaller file size and faster downloads, but lower image quality.
         • Lower compression creates larger file size and longer download time, but better image quality.

Dimensions

If you know the resolution of the projector you'll use to present, you may want to optimize images for the sharpest results.
Note: These are full-screen dimensions. Make images smaller if they won't fill the entire screen.

  • UXGA projectors: 1600 X 1200 pixels (10” x 7.5” at 160 ppi)
    This size image will also look good on older XGA (1024 x 768 pixels) or SVGA projectors (800 x 600)
  • XGA projectors: 1024 x 768 pixels (10” x 7.5”  at 96 ppi)

Presentation Compression

If you prefer to let your presentation software handle resizing and compressing oversized images, once you've finished composing your presentation, look for a command to compress all the images at once.

Sharing presentations online

In Moodle or on another website, consider saving a PDF of PowerPoints of Keynotes rather than posting the presentation file. Files will download more quickly and if your audience doesn't have the same software or fonts installed on their device to view the content.

Video Guidelines

File types and color mode

  • The PNG file type works well in video.
  • Image files must be in RGB or Grayscale mode* (not CYMK).

Pixel Dimensions for Video

Before inserting a still image into a video project, crop it to fit the video's aspect ratio (4:3 or 16:9). To preserve detail when using zoom & pan effects, size at the largest dimensions the image has in the project.

4:3 ratio iMovie HD6 & iMovie DV 720 x 528
  NTSC DV  720 x 480
  DVCPRO  1280 x 1080
16:9 ratio HDTV 720p 1280 x 720
  HDTV 1080p 1920 x 1080

  

Print Guidelines

Desktop Printing

  1.  Know the target print size. (e.g., 4 x 6 inches, or 11 x 17 inches)
  2. Resize and crop image to correct resolution for printer and image type.
         • 150-720 ppi for photos, 300-1200 ppi for line art
         • 240, 360 or 720 ppi for ink jet printers
         • 300 or 600 ppi is typical for laser printers
  3. Save a copy of the resized image as PSD, TIFF, or highest quality JPG.
  4. Go to File > Page Setup to select paper size & orientation.
  5. When possible, use color management (ICC) profiles to match ink/paper/printer (some printer drivers do this automatically).
  6. Send to printer.

Using a Commercial Printing Service

  1. Know target print size.
  2. Ask the print service to give you specifications for:
         • Pixel resolution
         • File format
         • Color space (RGB or CMYK-- and if CMYK, ask for a conversion profile)
         • How to deliver (E-mail, upload to their Web site, etc.)
  3. Save a copy of the prepared image.
  4. Deliver the file.

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