The phrase "which emphasised" is grammatically correct and can be used in written English.
It is often used to introduce a subordinate clause that provides more information or clarification about the main clause. Example: The speaker's body language, which emphasised confidence and authority, captivated the audience.
In 2007, she backed The Secret, which emphasised the power of positive thinking to "attract" good things into your life.
The most compelling texts were invariably those which emphasised the horror and futility of the first world war.
Manchester United won 2-0 at Old Trafford that day, a result which emphasised their contrasting trajectories.
This was seen as a professional type of service, which emphasised that those carrying it out should have a degree in social work.
Goldsmith was influenced by the sociological writings of Karl Polanyi, which emphasised the way economies are embedded in society and culture.
What we'd now call a marketing strategy was created around her, which emphasised her virginal innocence, her spiritual purity, her "authenticity".
From such disparate sources Mayfield developed a highly individual sound, which emphasised the bass strings and electronic effects such as reverb and echo.
High-definition cameras mounted on the boats beamed back gripping images, which emphasised the boats' speed and the perpetual motion of the sailors on board.
Two years ago it unveiled a development plan known as "Challenge 2008", which emphasised the need to build brands and concentrate on cutting-edge technologies.
Mr Osborne's recent budget, which emphasised investment and offered tax cuts to low earners and pension reforms for the old, made a fair stab at that.
He matured in that peculiarly Scottish working-class environment which emphasised learning and literature, so though he had little formal education he quickly became absorbed into a culture that regarded books as treasures.
