Answer the question at the end by quoting:

Edward Henry Weston (March 24, 1886 - January 1, 1958) was a 20th-century American photographer. He has been called "one of the most innovative and influential American photographers..." and "one of the masters of 20th century photography." Over the course of his 40-year career Weston photographed an increasingly expansive set of subjects, including landscapes, still lifes, nudes, portraits, genre scenes and even whimsical parodies. It is said that he developed a "quintessentially American, and specially Californian, approach to modern photography" because of his focus on the people and places of the American West.
Weston always made contact prints, meaning that the print was exactly the same size as the negative. This was essential for the platinum printing that he preferred early in his career, since at that time the platinum papers required ultra-violet light to activate. Weston did not have an artificial ultra-violet light source, so he had to place the contact print directly in sunlight in order to expose it. This limited him to printing only on sunny days.  When he wanted a print that was larger than the original negative size, he used an enlarger to create a larger inter-positive, then contact printed it to a new negative. The new larger negative was then used to make a print of that size. This process was very labor-intensive; he once wrote in his Daybooks "I am utterly exhausted tonight after a whole day in the darkroom, making eight contact negatives from the enlarged positives."  In 1924 Weston wrote this about his darkroom process, "I have returned, after several years use of Metol-Hydroquinine open-tank" developer to a three-solution Pyro developer, and I develop one at a time in a tray instead of a dozen in a tank." Each sheet of film was viewed under either a green or an orange safelight in his darkroom, allowing him to control the individual development of a negative. He continued to use this technique for the rest of his life.  Weston was known to extensively use dodging and burning to achieve the look he wanted in his prints.

How did he use this technique to his advantage?

This was essential for the platinum printing that he preferred early in his career, since at that time the platinum papers required ultra-violet light to activate.

Some context: Daniel Dodd "Dan" Wilson (born May 20, 1961) is a singer, songwriter, musician, producer, and visual artist. His songwriting resume includes "Closing Time", which he wrote for his band, Semisonic, "Not Ready to Make Nice" (co-written with the Dixie Chicks) and "Someone like You" (co-written with Adele). He earned a Grammy nomination for "Closing Time" (Best Rock Song) and won Grammys for Song of the Year ("Not Ready to Make Nice" in 2007) and Album of the Year (which he won in 2012 as one of the producers of Adele's 21). In addition to being the leader of Semisonic, Wilson has released several solo recordings, including the 2017 release Re-Covered.
Wilson co-wrote three of the songs on Adele's multiple-Grammy-winning 21, "Don't You Remember", "One and Only", and, most notably, "Someone Like You", which became a number one hit in the US, UK, Ireland, Australia, and New Zealand was a top ten hit around the globe. As a producer of this track, on which he also played piano, Wilson shared in the 2012 Grammy Award for Album of the Year.  In an interview with American Songwriter, Wilson recounted the writing and recording of "Someone Like You":  The recording on the album was intended as a demo. I was thinking, "Oh, they're going to make a big version of this, strings and angelic choirs, like a big Chrissie Hynde power-ballad." But by the end of the first day, the demo was sounding lovely, and very affecting, but it was only half-written, there were no words on the second verse or the bridge as I remember. Adele came to the studio the next day and said, "I played it for my manager and me Mum." I was a little nervous about this because I don't like people to hear works-in-progress. I asked her what they thought of the song. "My manager loves it and me Mum cried."  "Someone Like You" won the 2012 Grammy for Best Pop Solo Performance, and as she accepted the award, Adele said, "I want to thank Dan Wilson, who wrote this song with me. My life changed when I wrote this song and I felt it before anyone even heard it."  "Someone Like You" was the most downloaded single of all time in the UK and was voted third most favourite single of the last 60 years in the UK.
Is 21 a single or an album?
A: album

IN: Percy Tyrone Sledge (November 25, 1940 - April 14, 2015) was an American R&B, soul and gospel singer. He is best known for the song "When a Man Loves a Woman", a No. 1 hit on both the Billboard Hot 100 and R&B singles charts in 1966. It was awarded a million-selling, Gold-certified disc from the RIAA. Having previously worked as a hospital orderly in the early 1960s, Sledge achieved his strongest success in the late 1960s and early 1970s with a series of emotional soul songs.

Sledge was born on November 25, 1940, in Leighton, Alabama. He worked in a series of agricultural jobs in the fields in Leighton before taking a job as an orderly at Colbert County Hospital in Sheffield, Alabama. Through the mid-1960s, he toured the Southeast with the Esquires Combo on weekends, while working at the hospital during the week. A former patient and mutual friend of Sledge and record producer Quin Ivy introduced the two. An audition followed, and Sledge was signed to a recording contract.  Sledge's soulful voice was perfect for the series of soul ballads produced by Ivy and Marlin Greene, which rock critic Dave Marsh called "emotional classics for romantics of all ages". "When a Man Loves a Woman" was Sledge's first song recorded under the contract, and was released in March 1966. According to Sledge, the inspiration for the song came when his girlfriend left him for a modelling career after he was laid off from a construction job in late 1965, and, because bassist Calvin Lewis and organist Andrew Wright helped him with the song, he gave all the songwriting credits to them. It reached No. 1 in the US and went on to become an international hit. When a Man Loves a Woman" was a hit twice in the UK, reaching No. 4 in 1966 and, on reissue, peaked at No. 2 in 1987. The song was also the first gold record released by Atlantic Records. The soul anthem became the cornerstone of Sledge's career, and was followed by "Warm and Tender Love" (covered by British singer Elkie Brooks in 1981), "It Tears Me Up", "Take Time to Know Her" (his second biggest US hit, reaching No. 11; the song's lyric was written by Steve Davis), "Love Me Tender", and "Cover Me".  Sledge charted with "I'll Be Your Everything" and "Sunshine" during the 1970s, and became an international concert favorite throughout the world, especially in the Netherlands, Germany, and on the African continent; he averaged 100 concerts a year in South Africa.

How long did the song stay at No. 1?

OUT: