Chroma key Chroma key is a technique for compositing two images or video streams together based on color hues , or their chroma range . Jim Henson used this method with the Muppets by way of dressing performers all in black to operate characters that would appear to exist unassisted against a backdrop . On the documentary " Inside the Labyrinth " , Henson makes note of this style of puppetry , saying that " velvet is probably the blackest fabric that you can use , so that ' s what they had to wear . " If the lighting is just right , the performers dressed in black velvet become almost invisible when in front of a background of black velvet . Often times , this background is then replaced by superimposing another background on top of it . This allows a character to be seen from head - to - toe , and move about freely , without any puppeteers visible . Henson described this process in the same documentary , explaining , " We shot the puppets first with a computerized camera and then we removed the black velvet and shot the background , using the computer to make the camera move at exactly the same speed and so forth . Then all of these elements were put together later in the laboratory . " This style of puppetry is based on " Bunraku " , which is a type of puppetry founded in Osaka , Japan , in 1684 . Traditionally , a Bunraku puppet is operated by three puppeteers . All three are dressed in black , but only one puppeteer shows his face during a performance . This is the performer who operates the puppet ' s head , a privilege which can take twenty to thirty years to earn . In an interview with Jim Henson , it was suggested that Bunraku was an inspiration for the Muppets . Henson corrected the statement : " No , I don ' t think so . . . . Bunraku is a marvelous and fascinating art form and puppetry form but , basically , I knew nothing about it until I had been working for a number of years myself . " A form of Czechoslovakian puppetry also involves performers that dress all in black . They perform in front of a black curtain with brilliantly colored puppets that are lit from the side and the top . This makes the puppeteer almost invisible from the audience . This style of puppetry is part of black light theater , and it has been used various times by the Muppets and The Jim Henson Company . Both of these forms of puppetry have also been used against a blue or green screen . At times multiple performers are used to operate a single character . Other times , only a single performer is needed to achieve the desired effect . " Sesame Street " . This form of puppetry is very frequently used on " Sesame Street " , especially during the show ' s Elmo ' s World segments . Dorothy imagines Elmo in various settings where Elmo ' s full body must be in view . In such instances , the puppet is referred to as " Active Elmo . " It has also been used in creating the Sesame Street openings since 1992 , and for a time helped to create the " Journey to Ernie " segments . These techniques are used to help Bert dance when he ' s " Doin ' the Pigeon , " and brought Baby Tooth and the Funky Funk to life . " See Also : " Elmo Variants " The Muppet Show " . These techniques were used numerous times on " The Muppet Show " , such as when Gene Kelly taught Kermit how to dance and the " Friendship " number from . Certain characters on the show such as the Clodhoppers , the Gawky Birds , and the Bossmen are almost always performed against black velvet , enabling them to dance with that week ' s guest star . Brian Henson discussed the way they ' re operated in his introduction for . On occasion , sketches on " The Muppet Show " which used “ Bunraku ” techniques did not always effectively hide the puppeteer . During the “ Disco Frog ” and “ Octopus ' Garden ” numbers , performers briefly become visible on screen . Movies and Specials . For " The Muppet Movie " , an elaborate sequence using Bunraku - style puppetry was staged in which Kermit and Fozzie would dance their way out of a jam at the El Sleezo Cafe . The end result appears almost effortless . In the documentary " Inside the Labyrinth " , Jim Henson explained the process involved in developing the wild antics of the Fireys : " When we first came up with these characters , we didn ' t really know how they would move . We had to put a series of puppeteers working with them just to figure out how they would move , what they were capable of . We tried manipulating them in different ways . . . We found each way of operating them would create different kinds of movement . " At least three puppeteers were used on each of the Fireys to create their movements . For the Creature Shop film " The Adventures of Pinocchio " , several different puppets were built to create the illusion of a puppet who had cast off his strings . One of these , considered one of the most difficult puppeteering tasks on the film , was a rod puppet based on Bunraku puppets . Up to five puppeteers would perform the character , oftentimes each puppeteer would be responsible for only one limb at a time . This version of the character was shot against a blue screen with the control rods all painted blue and the puppeteers dressed in blue body suits . Director Steve Barron spoke of the advantages of this puppet , explaining , " John Stephenson told me that we ' d have to get the puppeteers as close to the body of the puppet as we could , and he was right . We had them six inches away from a leg or arm , and their performances were superb . But as we gave them longer rods or cables , then we lost all the subtlety . " " The Jim Henson Hour " . The " Jim Henson Hour " special " The Song of the Cloud Forest " marked the first time that the Henson Company shot an entire half hour show without a background . Instead , the set and all performers were hidden in black velvet . The velvet backdrop was then replaced , using computer technology , with a bright , colorful rain forest .