Sorry if this has been covered before, but in light of some talk about celluloid knife handle deterioration on another post, this might be a good topic to re-approach.
Celluloid type thermoplastics were developed in the mid 1800s and were commonly used as a knife handle material from the late 1800s to around the mid 1900s. (and again later on) Celluloid in clear form was perfect for use in "picture" handled knives from early cutlery companies such as "Novelty", "Canton", and "Aerial", who put actual film pictures under the clear cell handles. Color was also added to to produce single and multi-colored handles. It's common knowledge that clear or light colored celluloid handles are the ones most likely to go bad BUT, dark colored cell handles can also deteriorate. Celluloid was initially a good material for knife handles which could easily be formed under a heat process and were relatively strong once finished. But, no one knew at the time that much of the celluloid used for a variety of purposes would eventually deteriorate and produce an acidic gas in the process.
Enclosed are pictures of a knife from the well respected German firm of "J. A. Henckels" which shows the classic signature of celluloid deterioration (out gassing). What's sadly interesting about this knife is that it can be seen just where the problem has started, which is under the handle and near the blade end. The top nickel silver bolsters and shield have discolored noticeably, and the back springs nearest the blades have started to red rust. The blades have fared better but still show rust areas. This Henckels knife was purchased many years ago in fine condition, but I broke my own rule in storing it in a knife roll along with many other knives. I knew it was celluloid but thought I was safe since it had black colored cell handles. Needless to say, I was shocked to find this folder had gone bad after routinely checking on it. Fortunately, no other knives were affected and I removed it and set it aside. I decided to leave it as is out in the open to see if it would get worse over time. After nearly two years, it has not changed...
A great many knife companies have used celluloid for knife handle material over the years and most have held up just fine. But with that said, most veteran knife collectors would advise that knives with celluloid handles should be kept in an open environment and with reasonable temperature and humidity conditions.
Celluloid type thermoplastics were developed in the mid 1800s and were commonly used as a knife handle material from the late 1800s to around the mid 1900s. (and again later on) Celluloid in clear form was perfect for use in "picture" handled knives from early cutlery companies such as "Novelty", "Canton", and "Aerial", who put actual film pictures under the clear cell handles. Color was also added to to produce single and multi-colored handles. It's common knowledge that clear or light colored celluloid handles are the ones most likely to go bad BUT, dark colored cell handles can also deteriorate. Celluloid was initially a good material for knife handles which could easily be formed under a heat process and were relatively strong once finished. But, no one knew at the time that much of the celluloid used for a variety of purposes would eventually deteriorate and produce an acidic gas in the process.
Enclosed are pictures of a knife from the well respected German firm of "J. A. Henckels" which shows the classic signature of celluloid deterioration (out gassing). What's sadly interesting about this knife is that it can be seen just where the problem has started, which is under the handle and near the blade end. The top nickel silver bolsters and shield have discolored noticeably, and the back springs nearest the blades have started to red rust. The blades have fared better but still show rust areas. This Henckels knife was purchased many years ago in fine condition, but I broke my own rule in storing it in a knife roll along with many other knives. I knew it was celluloid but thought I was safe since it had black colored cell handles. Needless to say, I was shocked to find this folder had gone bad after routinely checking on it. Fortunately, no other knives were affected and I removed it and set it aside. I decided to leave it as is out in the open to see if it would get worse over time. After nearly two years, it has not changed...
A great many knife companies have used celluloid for knife handle material over the years and most have held up just fine. But with that said, most veteran knife collectors would advise that knives with celluloid handles should be kept in an open environment and with reasonable temperature and humidity conditions.
