The National Library is introducing amazing new technology which means people can do online searches through handwritten documents from the past.

For professional historians and for the army of family historians, it will no doubt be a marvel.

Up until now, anyone interested in looking at a handwritten letter in the 15 kilometres of boxes on shelves in Canberra would have to go to the building itself. The box would be taken off the shelf and brought to a desk for the actual bit of paper to be read. And readers wouldn't be able to search through it without actually reading the thing.

But the new technology means those handwritten sheets of paper can be viewed from anywhere.

They might be family papers or the rainfall records of a squatter's property deep in the 19^th century bush or, to take a grander example, letters to and from Robert Menzies.

"It's really a massive leap forward," said the library's director-general, Marie-Louise Ayres.

So if you're trying to trace your family tree with the Library's Trove online archive, the software makes it much easier to travel back through the records.

Dr Ayres thinks the innovation will let family historians and professional historians dig deeper.

"If you put curious Australians together with a magnificent collection, you will see magic happen," she said.

There are two steps that make up the leap in possibilities: firstly, all those letters and diaries and shopping lists from the past have to be digitised - that is, scanned and turned into pictures which can be put online. That's the very easy bit. A revolution it is not.

The not-so-easy, and new, bit is to introduce technology which can look at handwriting - sometimes bad, scrawly handwriting - and turn it into text which can be searched.

The library has been working with big tech companies. The result is that about 10,000 handwritten pages are now on the library's Trove online archive, and 2000 of them are now searchable, said Eric Swain who directs the program.

The Library's going to make a big push in 2024 to get more available. Eventually all its 9.5 million handwritten pages will be searchable.

The computer is not perfect at reading human handwriting. It gets scrawls wrong, so the National Library will be relying on its army of volunteers to correct the machine. There is a community of unpaid but immensely keen helpers who check accuracy.

Take an example from a letter written by the poet Banjo Paterson to his wife in 1905.

It starts "Dear Alice" in reasonably neat handwriting. On the Trove website, the words "Dear Alice" appear as type in the box to the left and as Banjo wrote it on the right. Scroll down the written page on the right and the type on the left moves to match.

Further down the letter, the handwriting gets worse so the machine gets it wrong: the machine can't translate, "Your loving husband" so it comes up with a jumble of letters. Alice, no doubt, could read Banjo's handwriting but the machine can't - yet.

But the machine is learning - fast.