Photographic solution in second best city (4,4)

I believe the answer is:

stop bath

'photographic solution' is the definition.
(chemical for developing photographs)

'second best city' is the wordplay.
'second' becomes 's' (common abbreviation).
'best' becomes 'top' (top can mean the very best).
'city' becomes 'bath' (English city).
's'+'top'+'bath'='STOP BATH'

'in' acts as a link.

I've seen this clue in The Times.

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