The judgment upholds an earlier High Court ruling in a case involving three computer games simulating pool. Under UK copyright law and EU Directives, the court ruled that the ideas behind the games cannot be protected by copyright, because copyright does not protect general ideas.
"Merely making a program which will emulate another but which in no way involves copying the program code or any of the program's graphics is legitimate," said Lord Justice Jacob, who gave the Court's ruling.
Nova Productions produced Pocket Money, a game based on pool. Mazooma Games produced a game called Jackpot Pool and Bell-Fruit one called Trick Shot. Nova claimed that the other two developers had infringed its copyright by using similar elements in their games to those it used in Pocket Money.
Nova did not claim, though, that the source code of its game had been copied or that the graphics had been copied. Those actions would have been clear infringements of copyright.
The company did claim that there was an extra right in the imagery used in its game, something beyond the copyright attaching to individual images and related to its use of a power bar used to judge the strength of a pool shot and of a cue control mechanism.
"Mr Howe invited us to find that there was in effect a further kind of artistic work, something beyond individual freeze-frame graphics," said Jacob in his ruling. "This was said to be because there is a series of graphics which show the 'in-time' movement of cue and meter. So, it was said, that what the defendants had done was to create a dynamic 're-posing' of the Claimant's version – one in which the detail of the subjects had changed, but an essential artistic element of the original was carried through to the Defendants."
The Court found, though, that for copyright purposes the moving images must be taken as simply a series of still images, each of which has its own copyright protection.
"A series of drawings is a series of graphic works, not a single graphic work in itself," said Jacob. "No-one would say that the copyright in a single drawing of Felix the Cat is infringed by a drawing of Donald Duck. A series of cartoon frames showing Felix running over a cliff edge into space, looking down and only then falling would not be infringed by a similar set of frames depicting Donald doing the same thing. That is in effect what is alleged here."
On that count alone the Nova case would fail, said the judge, but he went on to rule on the other issues in the case.
He said that some copying of another person's work is permitted, and that to infringe copyright it must be 'substantial'.
Jacob also said that there are some parts of the creative process which are not protected by copyright law, which only gives legal protection to very specific things. "Not all of the skill which goes into a copyright work is protected – the obvious example being the skill involved in creating an invention which is then described in a literary work," he said. "An idea consisting of a combination of ideas is still just an idea. That is as true for ideas in a computer program as for any other copyright work."
On the protection of ideas, Jacob quoted an opinion he gave himself in an earlier case. "The true position is that where an 'idea' is sufficiently general, then even if an original work embodies it, the mere taking of that idea will not infringe," he said in that ruling in 1994. "But if the 'idea' is detailed, then there may be infringement. It is a question of degree."
The taking of a plot (i.e. the 'idea') of a novel or play can certainly infringe if that plot is a substantial part of the copyright work, he said in that dispute between Ibcos Computers and Barclays Mercantile.
The general nature of the ideas which Nova was seeking to protect was the downfall of its argument on the basis of literary copyright. "The appeal on literary copyright fails on the simple ground that what was found to have inspired some aspects of the defendants' game is just too general to amount to a substantial part of the claimants' game," said Jacobs. "The Judge's evaluation, far from being wrong in principle, was right when he said 'they are ideas which have little to do with the skill and effort expended by the programmer and do not constitute the form of expression of the literary works relied upon'."
The protection of such general ideas is not only not a part of copyright law or the relevant European directives, it is something that could be damaging to businesses, the Court of Appeal found.
"If protection for such general ideas as are relied on here were conferred by the law, copyright would become an instrument of oppression rather than the incentive for creation which it is intended to be," said Jacobs. "Protection would have moved to cover works merely inspired by others, to ideas themselves."
The decision backs a 2004 ruling in easyJet's favour after it was accused of infringing copyright in an airline booking system. The budget airline had commissioned a system that emulate the look and feel of another system built by a company called Navitaire. This was achieved without copying source code and the court rejected the main claim of infringement.