As Parks Canada renews its search for the lost Franklin ships, its scientists know the discovery of a shipwreck is a major archeological event that only marks the start of more exploration.

"A lot of interesting discoveries are actually made in the laboratory," says Ryan Harris, a senior underwater archeologist with Parks Canada. "A lot of interesting nuances are actually teased out by analysis."

The Canadian government announced Thursday that it is launching a search for the two ships involved in Sir John Franklin's doomed 1845 quest for the Northwest Passage. It is the fourth government-led expedition over the past five years, and is by far the biggest, involving a much larger alliance of federal departments and other public and private interests.

• FULL COVERAGE: Searching for Franklin

Artifacts brought to Parks Canada's lab in Ottawa are treated and preserved so they can eventually be put on display. Anything recovered from the ocean, such as the artifacts from HMS Investigator, a ship that got stranded and sank in its search for the Franklin ships in the 1850s, must be constantly kept wet to keep them from drying out.

Those artifacts include a musket, the remains of a shoe and a piece of copper sheeting from HMS Investigator's hull.

"Our conservators here in the lab often are challenged with trying to stablize and treat artifacts that have not been dealt with before," Harris says.

"It's important to conserve and protect these sort of artifacts because they're quite unique."