A soft pencil can be produced using either waxes or oils ( or a mixture) and the softness will usually be down to a higher percentage of the hydrocarbons.For example Caran d’Ache use waxes and oils in their production linesPablo is a medium hard and well regarded coloured pencil which I had always understood to be made with oils. I have now been corrected.Pablo is manufactured using a process that takes a blend of ingredients ( pigments, gum binders and fillers ) and later adds some wax.. Caran d’Ache tell me : The process is what we call the non direct process. Leads are made of powders (pigments, of course, talcum and clay) and binders (always 2 kind of binders - gums). The leads are first extruded, dried for 8 hours and then soaked in molten waxes for 24 hours (like chips). This is the non direct way to impregnate the leads with wax. In this case, the content of waxes is less than 10% of the total weight of the lead.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, and a further benefit is the fact that the low level of wax will be unlikely to produce a bloom in the final artworkLuminance is a soft oil based coloured pencil which is designed not to produce a bloom.In this case Caran d’Ache tell me :LUMINANCE is a mainly oil based and direct pencil. Leads are made of powders, waxes, and hydrogenated oil (solid, not liquid), and natural organic binder (gum). The leads are first extruded, then dried during 8 hours and then stay in stock during 2 months before being used to make the pencils. Direct, in this case, mean that the waxes (and oil) are directly incorporate in the recipe. Leads are not soaked. In this case, the content of waxes is less than 30% of the total weight of the lead.The higher percentage of waxes and oils gives the softer feel to the pencils, the higher oil content gives the protection against blooming.What of other brands ?Frankly, I don’t know, as the manufacturers are not as forthcoming as the people in Geneva.We know that Prismacolor are the most frequently quoted source of complaints about wax bloom.I assume therefore that they have a high wax contentI believe Derwent Coloursoft also use a high level of waxes, though I have not heard complaints about blooming - perhaps Derwent are not being used so much in hot and humid conditions.Derwent’s latest ( 2018) lightfast pencils is oil based, 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 my source at Caran d’Ache may aid those who want to understand the subject better :blooming appears when you put down heavy layers or the artwork is sensitive to humidity, but it can also be a problem of "bad" formulation. If you mix vinegar and oil, you know what happens ? They can separate.Archaeologists have found roman coins which were made (2000 years ago) with a mixture of silver and bronze, and when you analyse these coins, you find that these 2 metals are now separate. The heart of the coin is pure silver and external part is pure bronze.This is to illustrate the fact that if you mix 2 synthetic waxes which are chemically not compatible, one of this waxes can migrate after weeks or months or years.I don't know the recipes of all our competitors, but when they talk about oil based pencils, I think that most of the end users consider that they use liquid oils (as the one they use in the salad). There is a chemical process which produces a reaction between hydrogen and oil and you get what we call hydrogenated oil, which is solid and looks like a wax. It is this product we also use in LUMINANCE,and the reason why I say that it an oil based pencil.I don’t think it matters if a pencil is made 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 ( and 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 - this is why they are so 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, and this is because there is a higher level of filler as against 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 !When I first set out to prepare these notes around 10 years ago, I did a lot of reading and on line research, but information was then very limited - and it is not a lot better today for commercial security reasons. I was led to believe then that oil based = harder, and wax based = softer. It was a reader of Topics who asked the question recently ( September 2016 ) which led to further enquiries of sources of information I didn’t have 10 years ago. There may still be statements buried in Topics quoting the old data, which I will correct as and when I find them.In the meantime - 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 seem to be proof against wax bloom, probably due to the low level of wax used.It is a tangled subject, not helped by lack of information from some of the manufacturers
SOME WAX TYPE PENCILS ARE MADE FROM WAXand are quite soft when you lay down colourSOME WAX TYPE PENCILS ARE MADE FROM A WAX /OIL MIXTURE and have a harder feel, but keep a sharper point.Some are made with a combination of oilsDoes it matter ?
Coloured Pencils are manufactured from a complex mixture of pigment ( to provide the colour ), wax or oil compounds ( to stick the pigment to the paper and provide a smooth lay down of the colour ), and clays and/or fillers ( which provide the strength for the core of the pencil to hold together and be strong enough to sharpen). Don’t get too hung up about the fillers - they are an essential to modify the colour ( This is where your paler shades of colour come from ) and also to give durability. Too soft a pencil core will be likely to shatter or break when being sharpened. Too hard a core resulting from a high filler content will result in it being difficult to lay down colour. It is all a matter of delicate balance.