Marco Schuffelen: On Editing Grapics for The Blind, Ch. 9, Diagrams

9. DIAGRAMS

Draw rectangles and connecting lines in different widths, connecting lines fat as they are the most important part of your drawing; quite often the rectangles around text might just as well be left out.

Simplify A Diagram

inkprint (ca 50K)

braille (ca 20K)

Do not copy complicated graphical elements in your schemes: just a rectangle and its name will do. A word like 'battery' makes sense to our readers, representing it by a series of straigt and curved lines will probably have no meaning.
Often abbreviations will have to be used, choose them sensibly; do not change existing codes.
In schematical representations like electrical diagrams, the current passes through a wire that should look different from the gauges and apparatus attached, as those might otherwise look like the wire branching out.

Line Widths: Electrical Diagram

inkprint (ca 10K)

wrong (ca 70K)

right (ca 55K)

Keep arrowheads some distance from lines they point at.
Take care at intersections: maybe change one of the lines' width for some distance to stay in the clear about which line continues where.

Generally a partial or complete description is to be preferred over copying a complicated diagram. It makes no sense if our readers have to go through a drawing with a lot of lines and abbreviations accompanied by a long list explaining those codes.

Editing A Very Complicated Diagram

inkprint (ca 185K)

wrong, part 1 (ca 65K)

wrong, part 2 (ca 60K)

better (ca 40K)

The data from most complicated diagrams can be given in an easy-to-read descriptions or tables. Even if the blind reader would eventually be able to make sense of these diagrams as pictures that time could be spent much more profitably elsewhere.

Diagrams That Are Better Fully Described (Inkprint Only)

decision chart 1 (ca 55K)

decision chart 2 (ca 45K)

oil distillation (ca 80K)

Look for original solutions to rendering colors etc. Again the main thing is to understand what the diagram is about.

Diagram Solutions

Row and Column Headers (Periodic Table, first 20 elements)

inkprint (ca 55K)

Braille (ca 55K)

Splitting Up (Full Periodic Table)

inkprint (ca 60K)

Braille, part 1 (ca 65K)