Books are designed using a Quark file, which can be changed relatively easily but designers only supply the pdf to the buyer and this cannot be changed.
This is interesting, since that author must own the copyright for published work but does he own the book design?
The nub of the issue is whether the author/publisher can require the designer to hand over the Quark file, since without it he is either stuck with the same designer or has to redesign from scratch.
Generally speaking the copyright in a book design rests in what the Copyright Designs and Patents Act calls the typographical arrangement of published editions (s 1(1)c ). While ownership of this copyright (as opposed to the author's copyright in the actual text itself) may belong to a number of people including the author in the case of self-publication, generally I would expect the publisher to take steps to become the owner of the copyright. In order to achieve this position the publisher will commission a designer and as part of the agreement, will expect the designer to assign copyright in the typographical arrangement to the publisher. Normally of course copyright in any commissioned work remains with the author/composer/designer/artist who creates it, unless either there is a pre-existing contract to the contrary, or the author/artist etc is an employee of the puiblisher.
Publishing a book is somewhat analogous to the recording of a song or piece of music, where the record company (as publisher) will generally own the copyright in the recording while the band etc will sign over the exploitation rights in their performance to the record company in exchange for royalties.
The answer to your second question really depends on how the agreement between the publsiher and designer is drawn up. If the designer assigns the copyright to the publisher, then he no longer has any rights in his work except the moral right to credited as the designer, assuming he chooses to assert this right. As with website design, a failure on the part of the commissioner to sort out the copyright issue in advance can lead to the designer/artist retaining copyright and thus a strangle hold over any future changes to the work, much in the way you describe in your last sentence.
As usual that is terrific advice.
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Thanks for this and your previous advice. It has been exceptionally helpful to me in navigating through this unfamiliar and complex part of the law