It’s well-established that film was optimized for light-skinned subjects. Manufacturers dodged allegations of racism by arguing that the principal market for film was light-skinned purchasers. They were simply meeting demand. If racism accounted for the fact that there was less demand from dark-skinned purchasers, that was a social problem. Not something that companies like Eastman Kodak could do anything about.
Except that they could. Part of the problem was that white photographers were complacent and simply assumed there was some immutable technical reason why film was the way it was. A notable exception came in 1977 when Jean-Luc Godard went on assignment in Mozambique and refused to use Kodak film.
It turns out manufacturers could address the issue if given the right incentive. For example, the vintage ID-2 Polaroid camera came with a boost that enhanced the flash by 42% which is exactly the additional level of light that black skin absorbs. The reason for the boost was to meet the requirements of the South African government. At that time, the apartheid regime required Blacks to carry a passbook and the photographs had to accurately reflect the skin colour of the subjects. It seems manufacturers were happy to meet the demands of apartheid but not the demands of a Black family trying to make a photo album.
Despite claims that the shift to digital photography has solved the problem, that isn’t universally true. Facial recognition algorithms have a persistent problem accurately detecting darker skinned faces. And since the principal function of these algorithms is to assist law enforcement and border controls, current shortcomings continue to promote the racial biases historically embedded in these roles.
For an individual photographer, or even someone wielding an iPhone, post-processing apps have made it easy to accurately correct for different skin tones. In my own work flow, I rely on programs like Lightroom and Nik Effects. There are still challenges, especially when people with radically different skin tone appear in the same frame. For the time being, I have adopted the practice of optimizing for the person with the darkest skin. It’s a bit like the practice news agencies have adopted of capitalizing the word Black. It’s one small step on a path to right relations.