In 1954, the psychical researcher Rudolf Lambert published a report revealing details about a case of fraud that was covered up by many early members of the Institute Metapsychique International (IMI).[166] Lambert who had studied Gustav Geley's files on the medium Eva Carrière discovered photographs depicting fraudulent ectoplasm taken by her companion Juliette Bisson.[166] Various "materializations" were artificially attached to Eva's hair by wires. The discovery was never published by Geley. Eugéne Osty (the director of the institute) and members Jean Meyer, Albert von Schrenck-Notzing and Charles Richet all knew about the fraudulent photographs but were firm believers in mediumship phenomena so demanded the scandal be kept secret.[166]

In 1876, William Eglinton was exposed as a fraud when the psychical researcher Thomas Colley seized a "spirit" materialization in his séance and cut off a portion of its cloak. It was discovered that the cut piece matched a cloth found in Eglinton's suitcase.[82] Colley also pulled the beard off the materialization and it was revealed to be a fake, the same as another one found in the suitcase of Eglinton.[83] In 1880 in a séance a spirit named "Yohlande" materialized, a sitter grabbed it and was revealed to be the medium Mme. d'Esperance herself.[84] https://drive.google.com/file/d/1lYr1mAeAFjvGgB1s67WfKkkmi_T4SIzM/view?usp=sharing
While I still am unsure why the translucence varies, I believe it’s a mixture of how closely they are still tied to the physical earth (more connected to earth, more ‘earthly’ looking, less connected, more ‘spirity’ looking). I also think it has to do with their skill level at being able to appear and the amount of energy they have to appear - it takes a lot of skill and energy to appear as a human in physical form without an actual physical body to work with!

Mediumship became quite popular in the 19th-century United States and the United Kingdom after the rise of Spiritualism as a religious movement. Modern Spiritualism is said to date from practices and lectures of the Fox sisters in New York State in 1848. The trance mediums Paschal Beverly Randolph and Emma Hardinge Britten were among the most celebrated lecturers and authors on the subject in the mid-19th century. Allan Kardec coined the term Spiritism around 1860.[12] Kardec claimed that conversations with spirits by selected mediums were the basis of his The Spirits' Book and later, his five-book collection, Spiritist Codification.
The techniques used in a love & relationships psychic reading vary depending on the psychic's abilities, preferences, and expertise. These techniques may include tarot cards, numerology, astrology, and other forms of divination. Love & relationship psychic guides rely on their clairvoyance, wisdom, and other medium senses to reveal information about your love life and romantic relationship to you. 

Senses used by mental mediums are sometimes defined differently from in other paranormal fields. A medium is said to have psychic abilities but not all psychics function as mediums. The term clairvoyance, for instance, may include seeing spirit and visions instilled by the spirit world. The Parapsychological Association defines "clairvoyance" as information derived directly from an external physical source.[37] https://drive.google.com/file/d/1RnQYA3idIVAwYhFUujDiS6HLuqkbAWeG/view?usp=sharing
Humans have been fascinated with contacting the dead since the beginning of human existence. Cave paintings by indigenous Australians date back 28,000 years, some depicting skulls, bones, spirits and the afterlife.[3] Other cave paintings in Indonesia date back a further 10,000 years.[4] Mediumship gained popularity during the nineteenth century, when ouija boards were used by the upper classes as a source of entertainment. Investigations during this period revealed widespread fraud—with some practitioners employing techniques used by stage magicians—and the practice began to lose credibility.[5][6] Fraud is still rife in the medium/psychic industry, with cases of deception and trickery being discovered to this day.[7]