The Public Catalogue Foundation reached a landmark point last week after nearly a decade when it completed the task of taking photographs of 210,000 pictures, ready to finish the website.
Sculpture may be added next. Meanwhile the PCF also aims to establish a panel of experts to help identify and detail works, and it is hoping that the trade will volunteer information where they can.
The database is expected to be a significant help to the trade in attributing unknown works on the market, as well as adding to dealers' and academics' knowledge of the work and style of artists. Its particular value will be in exposing works that are usually kept out of sight in museums, galleries and other public institutions across the country.
PCF is a charity which provides the resources for the BBC to host the paintings and information on its online Your Paintings facility, with the project's supporters including Christie's along with dealers Blain Southern, Hauser & Wirth, Hazlitt, Gooden & Fox, Liss Fine Art, Lisson Gallery, Philip Mould & Company, Richard Green Gallery and Simon C. Dickinson.
PCF director Andy Ellis told ATG: "The idea behind it is the nation has a wonderful paintings collection and 80% is in store, not on view, and a good two-thirds of it has probably never been photographed, so this public collection is there but not really known about yet. This project was set up to change that.
"The photography which finished last week has taken almost ten years, and last Thursday we took our last photos at the National Football Museum in Manchester, which has over 50 paintings, and over the next few months the photos will be processed, edited and 40,000 paintings will join the site in December, taking it to 210,000. That will be approaching 2800 collections on the site, across the UK.
"The research has been very thorough and participation rates have been very high - close to 100% from museums and town councils, all but a handful of universities, probably 80% of hospitals."
When the PCF was set up in 2003 it produced paper catalogues only, but by 2007 it realised that online access was necessary to bring it to a wider audience, and Mr Ellis said the BBC "saw this as being very much in tune with their remit to increase access to the arts".
Some 45,000 artists feature on Your Paintings, with the record number of pictures - 982 - attributed to one artist, being those of 19th century naturalist Marianne North, who has a gallery dedicated to her work at Kew Gardens.
Mr Ellis, who formerly worked in research for banks, is eager for the art trade to become more involved, not least because of funding (only 15% of PCF's money comes from public sources and the project has cost about £6m so far).
"From talking to dealers, I know many have found the site and because I go to the art fairs quite often, doing a bit of marketing, I know awareness has increased, but my guess is half of the dealers do not know about it," he added.
"Museum cutbacks in fine art curators, for example, mean lots of information is missing on these paintings and that's where the art trade can help perhaps. Our guess is about 10% of the paintings do not have artist attributions - 20,000 paintings, that's a big number - and there are plenty of sitters without names, so one thing we are going to try to do is set up the Oil Painting Expert Network, some time next year if funding allows, that would allow collections to go through a central point, and ask questions to experts."
Such help would be on a pro bono basis when the experts had time, slowly increasing the knowledge.
Mr Ellis said there were simply too many watercolours for them to be added to the database, "but we are seriously considering doing sculpture. Hopefully the funding will be a bit easier, as well, next time round".
Jane Hay, managing director of Christie's UK, said: "We congratulate the immense efforts of the PCF who have created a huge resource which benefits anyone with an interest in art, in terms of both appreciation and scholarship.
"This project has opened up a huge resource which makes previously hidden information accessible to the public, in terms of individual artists, as well as individuals, places, occasions and more. This will increase the public's awareness and appreciation of what they own, while also offering historians and art scholars an extremely rich and valuable source of information."
Simon Dickinson, one of the patrons, said: "I think it has more potential at the moment but it is a good thing to have done and could be very useful. It is a very interesting concept and it is always useful to know where everything is, such as different versions of a picture."