Ed Bush supplies some detail information on how Mr. Carder did his post production signature.
While making a study of Mr. Carder’s signatures a few years ago, I made copies of dozens of his signatures written over the years 1878 to 1963. The signature on the shade is almost exactly in the style he was already using in 1885. One distinguishing characteristic of a genuine Carder signature from then on is that he lifted his writing instrument after the letter “r” and began anew with the “d”. This left a gap between these two letters. The gap may be inadvertently missing on Steuben pieces when he wrote without support for his wrist, but I have no doubt that he always lifted the grinder after the letter “r”. Signatures on two of my Steuben pieces, however, have wider gaps in the line than usual. It is my opinion that any signature where the word Carder is clearly written with a continuous line was written by someone else.

Regarding the signature on the shade, the gap is almost nonexistent, but the writer clearly lifted the grinder after the letter “r”, and it appears genuine to me. The unusual smoothness of the signature is probably the result of Mr. Carder being able to support his wrist on the table while operating the grinder inside the shade.

Incidentally, the engraved signatures that I have seen on Intarsia ware always have the “r” and “d” joined, and therefore aren’t strictly facsimiles.