Student's Tactile Preferences for PIAF/Swell Machine Graphics

After the numerous Paths to Technology posts about Creating Tactile Graphics Images series, the practical blogs with activities (each with accompanying free PIAF-ready printable images) and the downloadable tactile graphic resources available in the Resource Library, the question came up about how to determine the 'ideal'  line and/or fill (width, shading, and texture) when creating your own images. Jessica, TVI extraordinaire, came up with a geat way to determine your student's tactile preferences!

Photo of the final tactile PIAF test document beside the original visual document in the Goodnotes app.

Jessica created a tactile graphic image with a range of line widths and color scales using the GoodNotes app. She created lines with various thicknesses (labeled in mm). Also included were shapes filled in with a highlighter and empty shapes created with the pen. In the GoodNotes apps, she selected the gradient pen color and custom highlighter and copied these to her page. Using the custom highlighter, she created a column of colored in squares - each square was filled in with a different gradient and each square was labeled by the highlight gradient number. She repeated the activity using the pen color gradients. Using the pen, she created a column of triangles (not filled in), then a scribbled (up/down coloring lines) beside the triangle and then random dots (each with a different gradient). The highlighter squares and pen images had darker gradient at the top descending to lighter gradient at the bottom.

Photo with the GoodNotes app screen showing Pen Color selected and column of black to white (gradient) options highlighted; same column of gradient images on the PIAF printed image are circled.

The GoodNotes pages was printed on Swell paper and then run the tactile graphics machine (PIAF) on heat level 10.

Photo of the tactile PIAF Test page as it comes out of the PIAF machine.

Jessica Concluded

Note: This is based on Jessica's ability to "feel"

  • .3 mm line was the thinnest that she could feel
  • Maybe .4, .9, 1.4, 2.0, for using a line with variations
  • Probably 8 or 9, to use as fill in (empty versus filled shape)
    • When distinguishing different fill/empty shapes, maybe 0, 6 and 100% black could be distinguished
  • Pen Color: .3 was the lightest that Jessica could detect but .3 dots were faint.
    • To distinguish between two pens, maybe 4 and 9, as 9 seemed to be subtly higher or sharper


  • Machines vary
  • Printers vary (may also vary if ink is new or running low!)
  • Student's tactile sensitivity vary

It is important to keep in mind who you are creating the image for and to determine the student likes/dislikes!

Download the Test Tactile PDF here.


Tactile Images; Download these free tactile graphic machine-ready images and links to corresponding posts (Tactile images sections are at the bottom of the Book Resource Library)