“Plainly there can be no copyright in an idea which is merely in the head, which has not been expressed in copyrightable form, as a literary, dramatic, musical or artistic work, but the distinction between ideas and expression cannot mean anything so trivial as that. On the other hand, every element in the expression of an artistic work (unless it got there by accident or compulsion) is the expression of an idea on the part of the author. It represents her choice to paint stripes rather than polka dots, flowers rather than tadpoles, use one colour and brush technique rather than another, and so on. The expression of these ideas is protected, both as a cumulative whole and also to the extent to which they form a “substantial part” of the work… Ladbroke (Football) Ltd v William Hill (Football) Ltd establishes that substantiality depends on quality rather than quantity… and there are numerous authorities which show that the “part” which is regarded as substantial can be a feature or combinations of features of the work, abstracted from it rather than forming a discrete part. That is what the judge found to be copied in this case… Generally speaking, in cases of artistic copyright, the more abstract and simple the copied idea, the less likely it is to constitute a substantial part. Originality, in the sense of the contribution of the author’s skill and labour, tends to lie in the detail with which the basic idea is presented.”
“The first step in an action for infringement of artistic copyright is to identify those features of the defendant’s design which the plaintiff alleges to have been copied from the copyright work. The court undertakes a visual comparison of the two designs, noting the similarities and the differences. The purpose of the examination is not to see whether the overall appearance of the two designs is similar, but to judge whether the particular similarities relied on are sufficiently close, numerous or extensive to be more likely to be the result of copying than of coincidence. It is at this stage that similarities may be disregarded because they are too commonplace, unoriginal or consist of general ideas. If the plaintiff demonstrates sufficient similarity, not in the works as a whole but in the features which he alleges have been copied, and establishes that the defendant had prior access to the copyright work, the burden passes to the defendant to satisfy the judge that, despite the similarities, they did not result from copying… Once the judge has found that the defendant’s design incorporates features taken from the copyright work, the question is whether what has been taken constitutes all or a substantial part of the copyright work. This is a matter of impression, for whether the part taken is substantial must be determined by its quality rather than its quantity. It depends upon its importance to the defendants work… The pirated part is considered on its own… and its importance to the copyright work assessed. There is no need to look at the infringing work for this purpose.”