I have been hired to do functional development for several web site redesigns. The company I work for has a relatively low technical level, and the previous development of the web sites were completed by a graphic designer who is self taught as far as web development is concerned.

My responsibilities have extended beyond basic development, as I have been also tasked with creating the development environment, and migrating hosting from external CMS hosting to internal servers incorporating scripting languages (I opted for PHP/MySQL).

I am working with the graphic designer, and he is responsible for the creative design of the web. We are running into a bit of friction over confusion between the boundaries of our respective tasks.

For example, we had some differences of opinion on navigation. I was primarily concerned with ease-of-use (the majority of our userbase are not particularly web-savvy), as well as meeting W3 WAI standards (many of our users are older, and we have a higher than average proportion of users with visual impairment). His sole concern was what looked best for the website, and I felt that the direction he was pushing for caused some functional problems.

I feel color choices, images, fonts, etc. are clearly his responsibility, and my expectation was that he would simply provide me with the CSS pages and style classes and IDs to use, but some elements of page layout also seem to fall more under the realm of "usability", which to me translates as near-synonymous with "functionality".

I've been tasked with selecting the tools we'll use, which include frameworks, scripting languages, database design, and some open source applications (Moodle for example, and quite probably Drupal in the future). While these tools are quite customizable, working directly with some of the interfaces is beyond his familiarity with CSS, HTML, and PHP. This limits how much direct control he has over the appearance, which has lead to some discussion about the tool choices.

Is there a generally accepted dividing line between the roles of a web designer and a web developer? Does his relatively inexperienced background in web technologies influence that dividing line?