I Love Lucy is an American television sitcom starring Lucille Ball, Desi Arnaz, Vivian Vance, and William Frawley. The black-and-white series originally ran from October 15, 1951 to May 6, 1957 on CBS. After the series ended in 1957, a modified version continued for three more seasons with 13 one-hour specials; it ran from 1957 to 1960. It was first known as The Lucille Ball-Desi Arnaz Show and later in reruns as The Lucy-Desi Comedy Hour.

Several classic episodes of I Love Lucy have been colorized. Star and producer Desi Arnaz had expressed interest in airing the show in color as early as 1955, but the cost of such a presentation was prohibitive at the time. The first episode to be colorized was the Christmas special. This special episode had been feared "lost" for many years, as it was not included in the regular syndication package with the rest of the series. A copy was discovered in 1989 in the CBS vaults, and was aired by CBS during December of that year in its original black-and-white format. In 1990, this episode was again aired in the days prior to Christmas, but this time the framing sequence was in color, while the clips from earlier episodes remained in black and white. The special performed surprisingly well in the ratings during both years, and aired on CBS each December through 1994. In 2007, as the "Complete Series" DVD set was being prepared for release, DVD producer Gregg Oppenheimer decided to have the episode "Lucy Goes to Scotland" digitally colorized, making it the first I Love Lucy episode to be fully colorized. Four years later, Time Life released the "Lucy's Italian Movie" episode for the first time in full color as part of their "Essential 'I Love Lucy'" collection. To date, the colorized "Lucy in Scotland" episode has never aired on television, but that episode, along with the Christmas special and "Lucy's Italian Movie," have been packaged together on the 2013 "I Love Lucy Colorized Christmas" DVD. In 2014, Target Corporation stores sold an exclusive version of this DVD that also included "Job Switching".

Using a quote from the above article, answer the following question: When did 'I Love Lucy' start being produced in color?
In 1990, this episode was again aired in the days prior to Christmas, but this time the framing sequence was in color,