Description: A design or picture is painted on absorbent paper with a colorless indicator, usually phenolphthalein or thymolphthalein. When it is sprayed with base, the picture appears. Both red and blue colors can be produced.

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Source: Shakhashiri, B.Z. Chemical Demonstrations: A Handbook for Teachers of Chemistry

Year or vol: 3 page: 47

Keywords: Invisible Painting, Spray To Show Picture, Indicators, Art