Drawing inspiration.

John Soane amassed drawings with didactic intent, his collection, now open to the public, extends from the Italian Renaissance to Regency England.

The opening of a new gallery this spring, by Sir John Soane's Museum, 13 Lincoln's Inn Field, gives the public access for the first time to Soane's extraordinary collection of architectural drawings. Or at least to about 50 of them at a time: there are over 30,000 drawings in the collection.

Soane's house, which is the substance of the Museum, is an intricate fusion of living quarters and repository of the architect's invention and manifest curiosity, and is of particular delight. The fascination of the place in which Soane's presence is still palpable has been augmented by new additions of which the Soane Gallery is a part.

It has been inserted into a room on the ground floor of No 12. This was the architect's first home in Lincoln's Inn and is of seminal interest, incorporating into its design as it does some of his early architectural forms and details. Owned by the Museum since 1969, the building has been used since its acquisition mainly for offices, research rooms and storage. The ground floor contains Soane's original breakfast parlour and dining room with the entrance hall to one side, and the task of rescuing these important interiors from oblivion has formed part of a larger five-year programme of building work on the fabric and interior of the museum. Work has been carried out under the enthusiastic curatorship of Peter Thornton, who retired in April, and an expert team including the museum's architect, Julian Harrap.

The breakfast parlour at the rear has been marvelously reclaimed by being decorated and furnished to Joseph Gandy's watercolour of the room, painted in 1798; while the dining room next door has been reserved for the gallery, with the precious drawings displayed in glass cabinets by Eva Jiricna Architects. Here, while Soane's elegant architectural shell with shallow cornices, arched recesses and mouldings was extant, little record remained of the room's original furnishing or decoration - except that it is known to have constituted Soane's first use of Pompeian Red. Margaret Richardson, who has succeeded Thornton as Curator, explains: 'The breakfast room was done up from contemporary evidence, but we didn't know what the front room looked like. We wanted a gallery and this was the only free and therefore logical place'.

The room has been painted a pale grey above the silver grain of quarter-sawn oak floorboards and provides a neutral background for Jiricna's minimalist intrusions. These are free-standing cabinets of various kinds, and as they do not impinge on Soane's architecture they were accepted after some hesitation by English Heritage. At the root of their design, and the reason for background neutrality is the extreme fragility of the drawings and consequently exigent brief. Lighting levels were restricted to 80 lux, so that even clothed in pale grey, the room is dim. The architects were asked to design cases that could take mounted and unmounted drawings of varying sizes and heights, as well as notebooks, folios, letters and models. The cases had to be airtight, capable of being sealed, secure and possibly airconditioned at some time in the future. At the same time, museum staff had to be able to get at the drawings and artefacts, and to put them up easily.

Jiricna's response to such exigencies is predictably sophisticated, though the simple transparent appearance of the cases suggest otherwise. Within the confines of the eighteenth-century room, four large cabinets are set out from the centre at 45 degrees one to another, their position carefully calculated. They are double-sided, rectangular on plan and square in elevation, and are composed of heavy white glass panels which are held by metal brackets on grey metal bases concealing electrical connections. So heavy are the cases that the floor has had to be strengthened. The free-standing cabinets are supplemented by smaller horizontal ones under screened windows, and by wall cabinets in the old entrance hall.

Light fixtures along the top emit a mixture of direct and indirect light - the latter to minimise the effect of reflection inside the cases. Within the cabinets the drawings and captions can be fixed magnetically to a double-sided screen that can be moved laterally to make room for two kinds of glass shelves - flat or angled with a lip and suitable for displaying objects or books, for eighteenth-century architects like Soane made great use of pattern books.

Now comes the ingenious part. The cases have two components: one being the stationary innards with magnetic screen and glass frame, the other is an outer glass shell that can be made, by plugging a motor into the base, to roll away to one side leaving the innards exposed and lighting disconnected. As can be imagined, the engineering must be precise because deflection of any kind would make the whole operation grind to a halt. Supplementary cases have outer shells that roll away horizontally and vertically, helped in the latter case by a belt-and-braces system of pulleys.

The advantages of the system are obvious. With all hindrances removed and the help of magnetic tape, positioning the drawings is easily done: there is no juggling with delicate exhibits, temporary nails and recalcitrant captions. The system permits adjustment, and there is the fact that the visitor is only about nine inches away from the drawings. Forestalling criticisms that such modern invention is inappropriate in this building, both Thornton and Richardson observe that having taken the decision to install a gallery, they 'loathed the idea of a Soane pastiche', and that Soane himself was inventor as well as architect, and a man who understood the importance of using the most advanced technology available. In this respect, the lighting (by SVM) is more worrying. Its greyish quality must affect the colours of the drawings, and the eyes of the average 50 year old visitor have to strain to read the captions.