Work on remote collaboration has often focused on the person space created by a conventional videoconference where the participants see each other's faces, but we argue that a task space containing shared visual information is more important for most tasks. Trends in display technology mean that large visual task spaces can be created to maximize the shared context between collaborators. We have created a system called the Escritoire that presents users with a desk-sized projected display with bimanual input that allows documents and images to be arranged and modified by multiple remote collaborators. We describe the software architecture, the protocol that is used between the client and server programs, and the pen traces we have added to allow participants to gesture to each other in the large visual space to enrich their communication. Our user trials have shown that participants were able to use the system with a minimum of training, and found the traces useful in the collaborative setting. In future we will be connecting three or more sites together to explore the issues that arise with multi-party interaction on large shared desks. Copyright © 2005 John Wiley & Sons, Ltd.

User interfaces using windows, keyboard and mouse have been in use for over 30 years, but only offer limited facilities to the user. Conventional displays are small, at least compared with a physical desk; conventional input devices restrict both manual expression and cognitive flexibility; remote collaboration is a poor shadow of sitting in the same room. We show how recent technological advances in large display devices and input devices can address these problems. The Escritoire is a desk-based interface using overlapping projectors to create a large display with a high resolution region in the centre for detailed work. Two pens provide bimanual input over the entire area, and an interface like physical paper addresses some of the affordances not provided by the conventional user interface. Multiple desks can be connected to allow remote collaboration. The system has been tested with single users and collaborating pairs.