During the sketching trip in Nantou County a few months ago, I saw some wonderful watersoluble ink sketches from Penang painter and sketcher Khoo Cheang Jin and was rather inspired. And recently during the AsiaLink Sketchwalk Hanoi 2019, I saw those from Bandung sketcher Muhammad Thamrin that were drawn with the Pentel Touch pens.
Using watersoluble inks to sketch is such an easy and quick way to make any sketch appear more lively.
After getting inspired, I need to try this technique myself, so I dug through my drawer to find some pens that I think have watersoluble inks.
The Pilot V Pen I had was surprisingly water resistant. Most Pilot pens I have, except those technical pens, use watersoluble ink so this is a surprise here.
It goes without saying you should always test your tools before you use them to avoid unwanted surprises.
The next pen is the Rotring Xonox drawing pen which surprisingly watersoluble. Somehow I had the idea that a Rotring pen that looked like a technical drawing pen would be using waterproof ink, but I was wrong.
The Pentel Tradio Stylo is a felt tip pen that I don't particularly like because it has the tendency to create splatter marks on watercolour paper. The ink in this pen is more soluble compared to other pens I've tested and it works great for watersoluble ink sketches.
The ink does not dissolve completely so the lines can still be seen. And the ink dissolves readily with rather dark values that you can dilute easily for lighter values. If the ink is too light, it's difficult to make it dark. But if the ink is dark, it's easy to make it lighter.
This is from the Pilot V series Hi-Tecpoint needle-point pens. The ink is watersoluble as expected but the ink does not dissolve to produce a dark value like the ink from the Pentel Tradio Stylo.
This is the Winsor & Newton Liquid Indian Ink which is watersoluble. Not all Indian inks are waterproof.
Here's the texture from the WN Liquid Indian Ink which is actually made from Chinese ink sticks.
If you want to use a combination of inks, it's best to use those with the same temperature. Like cool grays with cool blacks, warm grays with warm blacks. Some black inks may look black when concentrated but when diluted with water can either appear, cool, warm or neutral. All these require testing.
Among all the pens I have, the Pentel Tradio Stylo is the one that works best for watersoluble sketching. Note that this pen is also sometimes called the Pentel Tradio Pulaman. This pen comes in black, red and blue.
One important thing to note about watersoluble ink is whether they are pigmented or not. Most watersoluble inks are made of dyes and are not pigmented so the colours would fade in the future. Even blacks may fade, sometimes into browns (such as the case for fading blacks from Sharpie markers). Because such watersoluble inks are not archival, I'm a bit hesitant with using them. But I guess using them in sketchbooks should be fine.
Pentel Tradio Stylo/Pulaman unfortunately is an expensive pen. Refills are available, but also expensive. The alternative is the less cool looking Pentel Stylo Sketch pens which use the same tip and ink.
I've not tried the Pentel Touch pen mentioned above though but I will in the future.