They're also brighter than cathode-ray displays, thanks to improvements in design and manufacture, as well as the introduction of blue LEDs, made widely available in the mid-1990s.

FORBES: Bright, Very Bright

Changes in ballot design and the introduction of electronic counting possibly led, either directly or indirectly, to an increase in rejected ballots.

BBC: NEWS | UK | Scotland | Ballot paper report at-a-glance