Photos: What a face mask looks like up close

Individual fibers in a cotton flannel face mask. The scale bar in the image is 25 micrometers, or millionths of a meter, wide.

Fibres of a face mask made of Rayon, which is considered synthetic but is derived from plants.

Polyester fibers in a face mask, manufactured using a process called extrusion. The scale bar in the image is 75 micrometers, or millionths of a meter, wide.

A cross section of a cotton flannel face mask and its over/under weave. The scale bar in the image is 125 micrometers, or millionths of a meter, wide (a bit wider than an average human hair).

Fibres of a polyester face mask. The scale bar in the image is 125 micrometers, or millionths of a meter, wide (a bit wider than an average human hair)

Polyester fibers in a face mask, manufactured using a process called extrusion in which the polymer raw material squeezes through an opening, like spaghetti coming out of a pasta maker. The scale bar in the image is 75 micrometers, or millionths of a meter, wide.

A false-color image showing a cross section of one layer of an N95 respirator mask, including filtering material, shown in purple, and protective material around it. The scale bars in the image is 250 micrometers, or millionths of a meter, wide.

A top-down view of a polyester face mask showing how the fibers stay nicely bundled. The scale bar in the image is 250 micrometers, or millionths of a meter, wide.

Top-down views of cotton flannel (L) and polyester face masks. The scale bar in the image is 250 micrometers, or millionths of a meter, wide.

Fibres of a face mask made of Rayon, which is considered synthetic but is derived from plants.