By the mid-1760s Copley was creating pastels in a rich range of vibrant hues that echoed his oil palette of that period. Joseph Barrell  for example, depicts a wealthy merchant posing in a bright green silk dressing gown and wearing his own hair rather than a wig. The pendant of his wife, Hannah Fitch (Mrs. Joseph Barrell) (about 1771, Museum of Fine Arts, Boston), shows her uncorseted in a vivid blue dress with a pink robe trimmed in ermine; the Barrells’ informal presentation and luxurious costumes follow English rococo precedents.

Mrs Joseph Barrell By John Singleton Copley: Born July 3rd 1738 Boston USA, Died September 9th 1815 London.
(emigrated to London in 1775).

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18th century people caught smallpox
on purpose on pest island vacations 

Shapley's Island--Small Pox Parties--Incidents and Pastimes. 
BEFORE the introduction of vaccination for the kine pox, which was not discovered until just before the close of the last century, all who wished to be secure from taking the small pox in the natural way, were vaccinated for it, and withdrew for three or four weeks from intercourse with the world. We have before us a letter in the hand-writing of Doctor Hall Jackson, dated at the Essex Hospital, Dec. 17, 1773, at which time he was a small pox patient It was on his return that arrangements were made for "a general inocculation in Portsmouth." From that time up to 1797, Shapleigh's Island, in this 
harbor, was used as the "Pest Island," and every few years parties went there to have the small pox. 
These small-pox parties were frequently made social gatherings -- there were more who spent a summer month in this way than at the watering places; they had one advantage over the latter amusement, for as they could but once be of such a party, it remained a novelty through life. 
We have before us a letter from Joseph Barrell, a merchant of Boston, dated July 8, 1776, addressed to Col. Joshua Wentworth, of Portsmouth, in which is this postscript: -- 
"Mr. Storer has invited Mrs. Martin to take the small pox at his house: if Mrs. Wentworth desires to get rid of her fears in the same way, we will accommodate her in the best way we can. I've several friends that I've invited, and none of them will be more welcome than Mrs. W." 
Sent from Joseph Barrell, 1776