What colors do gram-positive and gram-negative bacteria stain?

I know this is more of a Biology question, but this is the closest thing I could find. Do you know what colors gram-positive and gram-negative stain?

First, the cells are stained purple with crystal violet. The slide is then treated with iodine/iodide solution, and then decolorized with a solvent (acetone, or alcohol) that dissolves the iodine/crystal violet complex. Gram-positive cells remain purple, and Gram-negative cells are decolorized. To see the Gram-negative cells, a red counterstain is used (safranin or acid fuchsin). After counterstaining, the Gram-positive cells are purple and the Gram-negative cells are red.

Author: Fred Senese senese@antoine.frostburg.edu



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