Lime - must be done with great care to avoid getting...

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Lime The best lime for fresco is pure white in color. This is important because of both the transparency and the bleaching ability of lime. Lime appears opaque when freshly painted, but over the first year of the fresco's life, the tonality of the painting will become even more unified because of the lime's bleaching ability which creates a snowy white reflecting surface under the colors. Carbonization continues for years and will slowly bring more depth and richness in color. Transparency will continue to grow in the depths and luster in the lights. Burned and slaked lime is calcium hydroxide and for fresco this mixture must contain no gypsum. Lime which has burned over wood fire is the best. Next the lime must be slaked for as long as possible, at least 24 hours. Slaking is the process of adding water to the powdered lime to turn it into lime plaster. The chemical reaction that takes place here gives off great heat, so slaking
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Unformatted text preview: must be done with great care to avoid getting burned. Using the slaking box, sift the lime into the box slowly, adding the fresh lime at the top of the box. At the same time allow a slow stream of water to pour into the upper box from a water-hose. Do not pour large amounts of lime in at one time. Use a hoe to slowly mix water and lime; it must be thoroughly wet, with no undisolved remnants remaining. Watch for hot dry piles which will overheat and burn the lime. As the lime-plaster becomes thoroughly mixed, hoe the lime-plaster toward the gate which leads to the lower box. The lime plaster must be stored for a minimum of a year, hopefully for two years. Storage in a pit is best, but steel drums which have been painted on the inside with asphalt varnish or baked lacquer also work....
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