Paper has 2 kinds of reciprocity failure, speed and contrast.

In speed reciprocity failure, the paper loses speed with exposures much above about 1 minute and it gains speed below about 1 second.

In contrast reciprocity failure, contrast goes down with longer exposure and up with shorter exposure.

These effects vary vastly among papers, but can be disastrous with VC papers where you are trying to design matched reciprocity failure between 2 emulsions.

Some papers have virtually no reciprocity failure, others have a lot. Some papers for example, are designed to work in different ranges. Digital papers are designed to work with high intensity short exposures and if you use them on-easel, they will respond differently than the mfgrs. data sheet.

Historically, Kodak made 2 ranges of papers. One for high intensity short exposures and one for low intensity long exposure.

PE