This stencil marking from Daniel Sewell's California studio is the only reported use of a 25¢ stamp by a studio.

Whether it originated on a document of some kind or an expensive photograph is open to speculation.
Interestingly, the name "Sewell" has been misinterpreted by collectors as "Schell" for many years due to the warped nature of this stencil, a point now clarified by the I.R.S records.
ex Morton Dean Joyce