Ahead of this year's conclave, spokesman Father Federico Lombardi said the chemical technique had been improved to ensure a clear color signal.

CNN: March 13, 2013 -- Updated 0018 GMT (0818 HKT)

One technique was to make sure there was a clear benefit for the audience.

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She added that as the course instructor concluded that the technique was so obvious that no demonstration was necessary, it was vital she should at least give clear and specific instructions about how to negotiate the pole, so as to control the speed of descent - but she did not.

BBC: South West Wales