"Conservation renews portraits of founding fathers"... also mothers. Abigail Adams' portrait is one of the paintings by Gilbert Stuart that have been cleaned up. From AP via Yahoo:
Stuart painted three portraits while Washington was sitting. One bust-length portrait he supposedly didn't like and rubbed out — but copied it several times before destroying it. One of Stuart's original copies is believed to be the "Vaughan-Sinclair" portrait that has been conserved, said portrait conservator Joanna Dunn.
She uses a mild solvent to remove the varnish with tiny cotton swabs to treat the paintings. Old restoration paint that no longer matches the original color also is removed. Damaged areas can be repaired with in-painting using a tiny brush filling in the losses of pigment to show the works as the artist intended. One of Stuart's paintings of his uncle, Capt. Joseph Anthony, has a severe tear Dunn is working to cover.
The most dramatic change as conservators demonstrate the process comes as the aged varnish is removed. The yellow layer has hidden Stuart's brushwork for decades since they came to the National Gallery of Art from private collections. The varnish also changes the color relationships in the paintings, making them look flatter.
"A painting is really like a trick of the eye," Dunn said. "It's a two-dimensional thing that's making it look three dimensional. So when you change those color relationships, you lose the depth of the painting."
Bright white collars have been restored, along with a glimmer of blue in John Adams' eyes and the details of Washington's face — the pink in his cheeks and his five o'clock shadow.
"Prior to cleaning, he was quite jaundice," Anderson said. "Now beautifully fresh, and you can see the life in his cheeks, the blood beneath his skin instead of just the yellow varnish. He has just emerged transformed by the treatment."
View a gallery of photos of the restoration in progress.
There’s also a video.