A lot of technology goes into pencils that most people don't think about; there's the core which needs a certain ratio of clay and graphite, how the wood slats come together to form the barrel of the pencil, the formula used to make a good, and much more. Today's pencil laboratory experiment was regarding water-soluble pencils, which have an obvious science-related trait: water solubility.
The goal of this experiment was to see what would happen to water-soluble pencils when placed in water for extended periods of time. Unfortunately, I neglected to choose a pencil that wasn't labeled as water-soluble for additional experimentation, but who cares about non-water-soluble pencils in water? They don't have applications in water and this was more of an exploration of an object that is commonly used in companion with water.
During this exploration, there were two pencils chosen, both from my favorite brand, Caran d'Ache:
Supracolor II Soft in Scarlet 070
- Technalo Water-Soluble Pencil in HB
These seemed to be the optimal choices for this exploration. The Supracolors are well-known to be one of the best choice for watercolor art and the Technalo has a graphite-based core. With two very contrasting pencils, unified by their water-soluble trait, these two pencils were optimal for this exploration.
- 2 tall glasses, 15.1 cm tall and 0.9 cm diameter
- 2 water soluble pencils, 17.5 cm in height, 0.7 cm diameter, 0.3 cm diameter core
- tap water, sourced from CWPE's sink, room temperature ~25˚C
water poured into the glass until it reaches 10 cm in height
- leave the glasses with water out for five minutes
- get cups placed appropriately for picture taking
- place pencils in
- after a minute, swirl the pencils continuously for 30 seconds
- wait and observe
Left: water in cups before placing pencils; right: after pencils placed in water
Left: after 30 seconds of swirling; right: one week after the start of the experiment
Left: Supracolor after 30 seconds of swirling; right: Supracolor one week after the start of the experiment
Split wood of both pencils
Thoughts & Conclusions
I really thought the way the wood split was interesting. Even before the wood had split, the sharpened, exposed part of the core also got larger. Perhaps that was the reason why the core split. Another explanation could be the glue that holds the two slats of the barrel together was affected by the water, but an experiment on a non-water-soluble pencil would have to be done. The pencil's wood and glue would have to be the same.
Although there was a lack of a control pencil (one that had all the elements of both these pencils aside from a water-soluble core), there's no way that a proper control could've been chosen. As you can probably see from the wide variety of pencils sold in the shop, even just by Caran d'Ache, it would be unlikely to find that perfect control pencil.
I actually ended up painting with the Supracolor core; after I cut the barrel in half, I used a brush with a water cartridge to paint with the Supracolor core. After the pencil was submerged for so long, the core was almost like an extremely thick, pigmented paint. I painted on my Standard Notebook in Mint by Iron Curtain Press and you can seriously tell that the core was very pigmented and vibrant. I also attempted to paint with the Technalo but that was fairly difficult; although I was able to coerce some pigment onto my brush, it was nowhere near as dark as if I wrote with the pencil.
My conclusion is that these water-soluble pencils are truly water-soluble, although some more than others. The Supracolor performed better than I expected and almost seems like the pencil has a core of dehydrated watercolor paint. The Technalo is obviously not as water-soluble due to its graphite base, but it still performed decently.
Future experiments in water-soluble colored pencils would be how different colors of Supracolors dissolve and whether there are differences in a, say, purple Supracolor versus a red Supracolor. Maybe certain colors, because of their different pigments, have varying levels of solubility. Another experiment could be done with Prismalos or Swisscolors, which are water-soluble pencils by Caran d'Ache.
My next plan for an experiment: rehydrating a dry eraser (you'll know what I'm talking about if you've used a vintage pencil with a problem like this)