Monday, October 22, 2018

Optimizing Graphics for Children with VI

The Animated Step-by-Steps® designed for children with Visual Impairments were created using high contrast graphics, presented on a black background.  The images are often outlined in white, to ensure that they 'stand out' on the page. 

When appropriate, I use the Correction feature in PowerPoint to make graphics lighter to promote better figure-ground contrast.

To  further enhance the 'figure-ground' differential, I typically create a narrow white border around the graphic. As illustrated in the image below, the white outline does indeed help the rock stand out against its black background and enhances the shape cues inherent in that object.  

When I bring images into PowerPoint, they are typically imported with a transparent background. For further information on creating images with transparent backgrounds please refer to a previous blog post.

The white outline can be easily achieved using a photo imaging program such as Photoshop or Photoshop Elements.  As programs vary greatly in their available tools, I will present two options for outlining an image.

Strategy 1: Adding a Stroke

- open the image in Photoshop or Photoshop Elements.

-use the magic wand to select the background of the image

-under Select on the menu bar, select inverse to highlight only the foreground, not the transparent background of the image.

-set the paint color to white
-set the paint brush size to the width of the line you wish to produce around your graphic (Note: this value will vary depending upon the dpi. of your image.
-select paths (under Window on the menu bar), then select stroke path.

-a white line will magically appear around the image.

Strategy 2: Using the Expand Selection Command

-open the image (with a transparent background) in Photoshop or Photoshop Elements

-create a second layer (use the icon with a turned up corner at bottom to create a new layer) and position it below the original layer.

-use the paint can to drop white into this layer. We will now call this the 'white layer'.

-use the magic wand tool to select the background of the image in the original top layer

-under Select (menu bar) select inverse to invert your selection, i.e. you have now selected the image as opposed to the background. Now select the 'white layer'.

-under Select (menu bar) select the Expand command from the drop down menu. Enter in a pixel value that will determine the width of your border (varies with the dpi of your image)

-select delete on your keyboard to eliminate the background in the white layer,  leaving a white border around the image. 

-save your newly outlined image as a png (the .png format retains the transparency of the background image)

You now have an image lightened and outlined in white that stands out beautifully on its black background. Perfect for students with Visual Impairment!

…’til the next post … 

Visit my website
Follow me on twitter
Follow me on facebook
Email me

©2018 Carol Goossens’, Ph.D.
Augmentative Communication Consultant
Speech-Language Pathologist
Special Educator