Is there a difference between wax or oil based pencils? Does it matter when it comes to coloured pencil painting?
Wax type pencils are quite soft when you lay down colour. Compared with wax type pencils, those made from a wax/oil mix can have a harder feel and keep a sharper point.
Coloured pencils are manufactured from a complex mix of pigment, to provide the colour, wax or oil compounds, to stick the pigment to the paper and help it glide on, and clays and/or fillers.
The latter provides the strength for the pencil core so that it holds together and is strong enough to sharpen. Don't get too hung up about the fillers - they are essential to modify the colour (this is where your paler shades come from) and also to give durability.
It is all a matter of delicate balance.
A soft pencil can be produced using either waxes or oils (or both together) and the softness will be down to a higher percentage of the hydrocarbons.
For example, Caran d'Ache use waxes and oils in their production line.
I always understood that the Pablo brand was an oil-based pencil. They are medium hard, and well regarded. Another artist corrected me. They manufacture Pablo using a process that takes a blend of ingredients (pigments, gum binders and fillers) and later adds some wax.
Caran d'Ache tell us...
The low level of wax in the final pencil means that there will be a medium hardness in the 'touch' as the pencil is applied to the paper. A further benefit is that this will be unlikely to produce a wax bloom in the final artwork.
Luminance are soft, oil based pencils which are designed not to produce a bloom.
In this case Caran d'Ache tells us...
The higher percentage of waxes and oils gives the softer feel to the pencils, the higher oil content gives the protection against blooming.
Frankly, I don’t know, as the manufacturers are not as forthcoming as the people in Geneva.
We know Prismacolor Premier are the most frequently quoted source of complaints about wax bloom. I assume, therefore, that they have a high wax content.
I believe Derwent Coloursoft also uses a high level of waxes, though I have not heard complaints about blooming - perhaps Derwent are not being used so much in hot conditions.
Derwent’s lightfast brand are oil based pencils, so this may indicate a trend.
I am not aware of complaints about bloom regarding other European manufacturers who mostly use a wax/oil blend.
An interesting additional note from our source at Caran d’Ache may aid those who want to understand the subject better...
I don’t think it matters if they make a pencil with wax, hydrogenated oils or a mixture of the two.
The factor that is most important is the percentage of oils and waxes, which then affects the softness. A soft feeling pencil will lay down colour more easily (but it will also be used up quicker). It will also be harder to keep a fine point.
The harder coloured pencils from the Artists and Studio ranges produced by Derwent contain more clay and also keep a fine point to enable fine detailed work to be completed - therefore they are much loved by botanical artists.
When you test out a brand for the first time, you often find that strong colour is more difficult to achieve from lower-priced coloured pencils. This is because there is a higher level of filler than the more expensive pigments. I will not go into pigments at this stage otherwise I will get hung up on lightfastness - which is another area altogether.
Ten years ago, when Peter first set out to prepare these notes, he did a lot of reading and online research. However, information was then very limited - and it is not a lot better today for commercial security reasons.
If you find a brand is subject to bloom, let me know (but I already know about Prismacolor).
Softer brands will lay down thicker layers of colour and bloom will be more likely (but not Luminance which is soft and designed to avoid bloom). The medium hardness of Pablo and Polychromos seems to be proof against wax bloom, probably because of the low level of wax used.
It is a tangled subject, not helped by a lack of information from some manufacturers.