What color is a cell?

Because most cells are invisible to the naked eye (with some exceptions, like the chicken egg which is all one giant cell) the scientific artist has to choose what color to make them. For the illustrations of cells in my project, I am going to use a color palette derived from pictures of cells that are stained with H & E, or hematoxylin and eosin. This combination of dyes is very often used to visualize cells for light microscopy. In fact, at a previous job, I personally spent many an hour in the lab at a microscope counting H&E-stained lung cells. Because of this tradition, it seemed like an appropriate choice for use in my project.

Click here to see a picture of cells stained with H&E. To make a long story short, hematoxylin is a dark blue-purple dye that is basic. It stains regions rich in DNA and RNA, such as the nucleus and ribosomes. Eosin is bright pink, and stains cytoplasmic protein.

For my illustrations, I created this palette by using the eye-dropper tool in Photoshop to sample the various colors from a few examples of H&E photomicrographs. The colors on the left are used for the color inside the cells, the second row is used for the stroke defining the edges of the cells, as well as organelles and details inside. The 3rd row is for the nucleus, and the last row is for highly eosinophilic structures like erythrocytes, or the bright pink spheres inside an eosinophil, which is what gives them their name.