Here at the Bray Animation Project, we have in our possession approximately forty films in the 28mm format. 28mm is a now-obscure and obsolete film gauge developed in the early 1910s as an alternative to theatrical 35mm film. It was also designed as perhaps the first non-flammable safety film stock which could be shown safely in schools, homes, churches, and other establishments that did not have fireproof projection booths.
It appears J.R. Bray made an agreement with United Projector and Film Corporation (and possibly other companies) sometime in the late 1910s to the early 1920s to distribute his studios' films in the 28mm format. Thankfully, while sometimes fragile, many of these prints have survived today for the simple reason that they are safety prints and are not subject to the far-worse deterioration that most nitrate prints will experience over time. You can read more about the United prints on this page of the Bray Animation Project website.
Thankfully, a hoard of 28mm films were found and sold on the public market last year and this provided, so far, the full extent of our 28mm Bray films collection. The films were in varying condition with the worst problem being shrinkage in some of the prints, which is thankfully 'relaxed' and partially solved with camphor treatments. Other than that, the prints were in relatively good shape, simply needing extensive cleaning.
With the help of a few colleagues, two of the prints have been professionally transferred to video so far. It is a painstaking and very costly process, so it may be some time before more of these prints are converted. For your enjoyment, below are some framegrabs from the two prints that have been transferred.
The original canisters for both films:
Bobby Bumps Gets a Substitute (1916)
Bobby Bumps' Incubator (1918)