Which layer of the epidermis allows light to penetrate?

The stratum lucidum is a thin, translucent layer of the epidermis that is found only in certain areas of thick skin, such as the palms of the hands and the soles of the feet. Its main characteristic is its ability to allow light to penetrate due to its clear appearance. This layer provides an extra barrier of protection, while still permitting some degree of light transmission, which is essential for maintaining the health and function of the living cells in the underlying layers.

In contrast, the stratum corneum is the outermost layer of the epidermis that consists of dead, keratinized cells arranged in layers that provide a protective barrier, but it does not allow light to penetrate effectively. The stratum granulosum contains granules of keratin and lipids, which contribute to the barrier function but also block light. The stratum basale, being the deepest layer, is responsible for the generation of new skin cells and is not designed to allow light penetration, as it lies below the other layers.