I want to buy the big set of colored pencils from the local manufacturer Koh-I-Noor (I have a set of Derwents and some Polychromos and kohinoors, and why not add another set a have more colors at hand
), but could not find on their website whether they were wax or oil based. So I e-mailed them and got a nice detailed answer which I think I might share with you, because it applies to all CP, not just the kohinoors.
(Moderators, if you think it's redundant, feel free to delete.)
We're pleased you like our products (yes, I oiled some tongues )
. Regarding your questions:
We offer artist grade colored pencils Polycolor and watercolour pencils Mondeluz (and some more, like Triocolor or the woodles pencils I saw in some e-shops including Dick Blick)
. The base of the pencil core is the same for both, made of kaolin clay, pigment and a binder based on dextrin.
The softness and whether the pencil will be watercolour or waterproof depends on the preparation of the lead - oil or fat based, or wax based. The wax can be emulsified or non-emulsified. Every manufacturer develops its own preparation procedure based on the composition of the lead. The preparation agents can be added into the cold material during mixing, and in that case it's the waxes; or the material can be mixed without preparation agents and the cores are then prepared in a hot bath - using oils, fats or fat+wax, which is our case.
The cold preparation is better for thicker leads - over 4 mm - the hot preparation is usually used for thin leads under 4 mm. The wax used in cold preparation must be partially emulsified, otherwise the mix would not be homogenous, or another binder than organic dextrin must be used. In hot preparation any binder is acceptable and the wax doesn't have to be emulsified. The material that would be cold prepared requires longer and more complicated mixing, but the folowing drawing and drying process is shorter and less complicated. Both methods have their pros and cons.
The Polycolor pencils are prepared using a mixture of fats and waxes, the pencils are waterproof. Thanks to the wax (paraffin) the pencil glides easily on the paper, the fat improves the trace (makes the core "break" and dislodge the colour particles on the paper) and makes it more compact.
The watercolour Mondeluz pencils are prepared in a hot bath using emulsified waxes. The lead accepts water and is water soluble. Emulsified waxes can be used in cold preparation, but the resulting leads would not be waterproof.
The basic material is the same for both Polycolors and Mondeluz and the leads are then prepared depending on the required product.
The woodless watercolour sticks are made just like the watercolour pencils, but the leads are thicker and coated with varnish.
I also asked about pastels, the manufacturer produces soft and extra soft pastels + pastel pencils and I wanted to know the difference between the soft and extra soft:
The pastel pencils leads are made of pumice, pigments and dextrin binder.
The soft pastels are made of talc, pumice, pigment and dextrin binder.
The extra soft pastels are made of talc, pigments and dextrin binder.
Regarding the hardness, in percentage it would look like this:
pastel pencils: 120%
soft pastels: 100-110%
extra soft pastels: 8% not sure this isn't a typo? anyway I'm gonna go buy the extra soft set right now, because I really want to try it!