who was handling its visual effects?
London-based company Double Negative
Harry Potter and the Order of the Phoenix (film)
The film required over 1,400 visual effects shots, and the London-based company Double Negative 
harry potter and the order of the phoenix movie summary In the fifth year of Harry Minister of Magic Cornelius Fudge has appointed a new Defence Against the Dark Arts professor: Dolores Umbridge. Umbridge immediately clashes with Harry and punishes him for his "lies" about Voldemort by forcing him to write a message with a magic quill, scarring his hand. Despite the concern of his best friends Hermione Granger and Ron Weasley, Harry refuses to report Umbridge's punishment to Dumbledore, who has mysteriously been ignoring Harry since the summer
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Harry Potter and the Order of the Phoenix (film) [SEP] Visual effects
The film required over 1,400 visual effects shots, and the London-based company Double Negative created more than 950 of them. Working for six months on previsualisation starting in September 2005, Double Negative was largely responsible for sequences in the Room of Requirement, the Forbidden Forest, the Hall of Prophecies, and the Death Chamber. A new character in the film, Grawp, Hagrid's giant half-brother, came to life by a new technology called Soul Capturing, developed by Image Metrics. Instead of building the character from scratch, the movements and facial expressions of actor Tony Maudsley were used to model Grawp's actions.