The Picro-Sirius Red Stain Kit (For Collagen) is intended for use in the histological visualization of collagen I and III fibers in addition to muscle in tissue sections. The PSR stain may be viewed using standard light microscopy or polarized light resulting in birefringence of the collagen fibers.

Light Microscopy
Collagen: Red
Muscle Fibers: Yellow
Cytoplasm: Yellow

Polarized Light Microscopy
Collagen Fibers: Yellow-Orange and Green Birefringence