Ask the chemist: Oil Paint FAQs

Oil paint is a traditional fine art medium, made by mixing a drying oil (typically linseed oil) with a pigment to form a smooth painting base.

Additives are sometimes included to adjust drying time or texture.

Winsor & Newton use fine art grade pigments, ensuring the best permanence, lightfastness and the overall archivability of the paint.

We use the same fine art grade pigments across our oil paint ranges, from student to professional tiers, with the main difference being pigment load (the amount of pigment in the paint).

A single-pigment (or mono-pigment) paint is made with a single pigment, which allows for clean colour mixing, as interaction between multiple pigments can lead to muddier (or desaturated) mixes.

Firstly, defining clear specifications for the paint we want to create, defining attributes such as glossiness, opacity, viscosity, etc.

We then contact our suppliers to find which raw materials work best to integrate into our planned formulation.

Once the raw materials are formulated and validated, the colour goes through extensive quality control and stability testing, following which it goes through production and ultimately ends up on store shelves.

Every paint colour undergoes quality control testing, checking across parameters such as fineness for grinding, viscosity, drying time, colour, texture, etc.

Artists' Oil offers a high pigment load alongside a wide range of over 135 colours in the range, with a number of them holding historical significance.

To add, many of these colours use single pigments, allowing for cleaner colour mixing and cleaner tertiary colours when mixed into an artists' palette. The Artists' oil range is generally very lightfast and permanent, as validated by our lab testing in-house and verified by third parties.

Grittier pigments can indicate that the grinding process and colour development of the paint was not optimal. For instance, having too much pigment in a paint colour can change the stability of the paint.

This is why Artists' Oil go through extensive quality control testing from batch to batch to ensure repeatability and consistency of colour so that the artist can get the same strong colour payoff from one tube to the next.

Winsor & Newton's Artists' Oil Colour range comes in a vast range of colours and a high number of single pigment formulations.

Winsor & Newton's Winton Oil Colour range uses the same pigments, the same oils, and the same grinding fineness as the Artists' Oil Colour range. The only difference is a lower pigment load in the paint, and less colours available in the range.

As an alternative, Winsor & Newton's Griffin Alkyd Fast Drying Oil range is based on an alkyd, which is technically very similar to oil. It offers enough time for blending, but it has a much higher drying speed compared to traditional oils.

Lastly, Winsor & Newton's Artisan Water Mixable Oil range is based on a water emulsifiable oil. It is similar to oil, but we are able to clean and dilute it with water, making it ideal for use in schools and homes without the need for solvents.

With regards to traditional oil paint, it depends on the colour. Some colours take several days, whereas others can take several weeks.

There's also an important difference between dried and cured. When an oil colour is applied and is dry to the touch, it doesn't mean that doesn't mean it's that all layers of the painting have dried. This is why we recommend for artists to wait up to a year before they varnish to make sure the paint is cured on the inside.

To adjust the drying time of the paint, a drying medium can be used. For example, a fast drying alkyd, like Liquin.

Whilst there's no guarantee, we would recommend using olive oil based soap. Formulation of archival colours and strong pigment load means that the paints are made to last, and this can be true of canvas as well as clothes.

Different types of solvents can be used, such as turpentine.

If you're looking for a solvent free option, we have a water-based brush cleaner that can also be used.

Oil paint isn't typically recommended for multi-surface use. We recommend using a primed surface.

Yes, you can paint with oils on acrylics. The best example of this would be every time you paint on a canvas that is primed with gesso.

There are two ways to test lightfastness. The first one is naturally, through applying the paint, place it into light and see how the colour varies over time.

Another way is synthetically in a lab, where we have something called a Q-Sun machine. Using this machine, the paint is exposed to intense radiation, light and temperature that simulates the effects of prolonged exposure to sunlight. This allows us to see how the colour varies after this exposure of 300 hours, allowing us to evaluate good and bad lightfastness.

Oil paint is not toxic. It goes through extensive regulatory validation before it is sold in any market.

It is safe to use indoors, however it's important to note that oil paint cannot be washed by water. Therefore, we have to use solvents to wash and dilute it, like turpentine.

It's very important to aerate the space or studio you're working in when using solvents, but it is safe to use indoors if you take the necessary precautions.

Keep it in a sealed package to avoid contact with the air, so it does not dry out and avoid extreme cold or heat temperatures.