What tactile images are and tips on how to produce them.
What tactile diagrams are
Tactile diagrams are images designed to be touched rather than looked at.
A tactile graphic:
- is not a straight reproduction of the print graphic, or a tactile “photocopy” of the original
- does not include the symbols expected by visual readers, such as:
- colour
- decoration
- artistic additions
How to produce tactile images
Decide whether to include an image
Decide if the picture adds anything to the understanding or if it just makes the document look more appealing. If it adds nothing, leave it out.
It may be more appropriate to describe the image in text or braille. It’s important to only describe what is in the image and not your own interpretation of it.
Braille is roughly equivalent in the space it takes up as 24-point size capital letter in print. This is useful to know if you are likely to need to add braille text.
If the image is essential to understanding, for example it’s a science or maths diagram, remember that some images only work on a visual level and no amount of modification will change this, for example 3D drawings. Sometimes a real object or model will work better.
Pupils will nearly always need some additional guidance and explanation of a tactile diagram.
Textures and raised symbols
Think with the fingertips not the eyes.
Don’t be too detailed. A pupil with a visual impairment cannot easily distinguish lines less than 6mm apart.
Be careful how you use textures and raised symbols. The higher they are, the more important they’ll appear to be.
For example, on a graph it’s the actual graph line that is important, not the grid lines. The graph line needs to be more dominant than the grid lines. In some cases, the grid lines can be left out altogether.
Proportion and scale
Keep the image to proportion wherever possible. Do not try for exact scale, Some indication of scale is important on maps.
One image may need to:
- be split into several tactile images
- to cover several pages, particularly maps
Explain this at the beginning of the image.
Titles, labels, and page numbers
Be consistent with the positioning of titles and page numbers.
Always put a title at the top to aid orientation of the page.
Avoid using:
- numbers for the key: use easy-to-remember initial letters and give a clue about what the item is, for example, m for male, f for female
- label lines as you would in print: try to get the tactile label next to the item it refers to