1980s, when it was picked up by the New Age movement. In 1977, American esotericist Christopher Hills published the book Nuclear Evolution: The Rainbow Body, which presented a modified version of Leadbeater's occult anatomy. Whereas Leadbeater had drawn each chakras with intricately detailed shapes and multiple colors, Hills presented them as a sequence of centers, each one being associated with a color of the rainbow. Most of the subsequent New Age writers based their representations of the aura on Hill's interpretation of Leadbeater's ideas. Chakras became a part of mainstream esoteric speculations in the 1980s and 1990s. Many New Age techniques that aim to clear blockages of the chakras were developed during those years, such as crystal healing and aura-soma. Chakras were, by the late 1990s, less connected with their theosophical and Hinduist roots, and more infused with New Age ideas. A variety of New Age books proposed different links between each chakras and colors, personality traits, illnesses, Christian sacraments, etc. Various type of holistic healing within the New Age movement claim to use aura reading techniques, such as bioenergetic analysis, spiritual energy and energy medicine. Auric energy In yoga participants attempt to focus on, or enhance their "auric energy shield". The concept of auric energy is spiritual and is concerned with metaphysics. Some people think that the aura carries a person's soul after death. Aura photography There have been numerous attempts to capture an energy field around the human body, going as far back as photographs by French physician Hippolyte Baraduc in the 1890s. Supernatural interpretations of these images have often been the result of a lack of understanding of the simple natural phenomena behind them, such as heat emanating from a human body producing aura-like images under infrared photography. In 1939, Semyon Davidovich Kirlian discovered that by placing an object or body part directly on photographic paper, and then passing a high voltage across the object, he would obtain the image of a glowing contour surrounding the object. This process came to be known as Kirlian photography. Some parapsychologists, such as Thelma Moss of UCLA, have proposed that these images show levels of psychic powers and bioenergies. However, studies have found that the Kirlian effect is caused by the presence of moisture on the object being photographed. Electricity produces an area of gas ionization around the object if it is moist, which is the case for living things.