In this last discussion of my favorite vintage pen materials, I am presenting celluloid. Why do I like celluloid you ask. Unfortunately, that is a detailed answer you see. There are two kinds of celluloid; one made with cellulose nitrate and another made from cellulose acetate. I have both but I prefer the cellulose nitrate. It has a warm feel, much like ebonite, and a pleasant camphor fragrance. It’s much easier to generate vibrant colors and interesting patterns.
Cellulose nitrate (Real Celluloid)
The primary ingredient of celluloid is cellulose nitrate. Cellulose is the most abundant organic polymer on Earth. Obtained primarily from wood pulp and cotton to produce paperboard and paper. Nitrating cellulose through exposure to a mixture of nitric acid and sulfuric acid produces highly flammable cellulose nitrate.
It was initially used as guncotton, a replacement for gunpowder. Cellulose nitrate was also used as a low-yield explosive in mining. So naturally, it should make a great medium for manufacturing pens – once it is plasticized with camphor, celluloid’s other essential component.
Spontaneous combustion is always a possibility; however, the most common failure of celluloid occurs as it ages. Exposure to the environment allows the camphor to sublimate at room temperature, reverting the celluloid to Cellulose nitrate. Another sublimation associated with exposure to excess heat affects nitrate.
Cellulose acetate (Fake Celluloid)
“Cellulose acetate is most commonly prepared by treating cellulose with acetic acid and then with acetic anhydride in the presence of a catalyst such as sulfuric acid.”
Cellulose acetate was made by dozens of companies with different brand names and formulations. According to Lambrou’s Fountain Pens of the World, there are four different cellulosic plastics used in fountain pens:
- Cellulose Nitrate (real celluloid)
- Cellulose Acetate
- Cellulose Propionate
- Cellulose Acetobutyrate
I ask, is cellulose acetate, etc. real celluloid? It is still being manufactured and called celluloid. Or is the determination of celluloid made because of cellulose?
Now for the bad news, both nitrate and acetate are classified as flammable substances, and subject to transportation restrictions plus storage and handling regulations. For this reason, contemporary celluloid pens are very uncommon; however, Italian companies, Montegrappa and Visconti manufacture pens from celluloid as does Onishi Seisakusho in Japan.
- Early billiard balls made of cellulose nitrate were known to explode occasionally.
- Cellulose nitrate-based film has spontaneously ignited and that which has not burned has in a large part decomposes to red powder.
- Allegedly a prisoner explodes a deck of celluloid playing cards to facilitate his escape.
How can I tell?
The simplest way to determine if celluloid is real is to take a whiff, it is all about the fragrance. Wet the pen and rub hard creating heat. It will not smell like plastic but like camphor. Honestly, I have no idea what camphor smells like but I can tell you a celluloid pen does not smell like a petroleum product, or a solvent.
You can also test by burning shavings. Acetate will have a vinegar smell and burn yellow while nitrate will smell of camphor and burn white. Yellow vs white seems like an inconclusive test.
For those with access to a microscope, place a shaving and lace on a glass slide. Add a droplet of acetone. If celluloid, it will promptly dissolve; casein, Bakelite, and acrylic will be unaffected. This test won’t tell us if the celluloid is real or fake.
Waxes have not been shown to benefit hard rubber, while they can damage celluloid by preventing the escape of the acidic gas by-products celluloid naturally produce. The wax seals the celluloid, preventing the nitrocellulose gas from escaping, it is retained in the celluloid hastening decomposition.
In conclusion, I test by smell. I like real celluloid because it has a warm feel and it smells good. To me, the aroma is earthy with a medicinal undertone.