Pthalo blue, pronounced “thal-o” is a popular blue hued oil paint. Although there are many other blue oil paints, such as ultramarine or cerulean, there are some characteristics that makes pthalo stand out. These differences are important to know for taking advantage of your paint mixing skills.
For reference, I have been oil painting for three years now almost daily. I have gone through multiple fazes of re-figuring out how to use my color theory knowledge. One of the biggest factors that plays into this is blue pigment.
Pthalo oil paint dries to a durable, glossy finish and can be used in a variety of painting techniques, such as glazing, layering, and impasto. However, it is important to note that Pthalo is a staining pigment, which means it can be difficult to lift or remove once it has dried.
If you want to know more about blue oil paint in general, and how to use it accurately, go check out my other post here.
What pthalo blue comes from
It is made from a synthetic organic compound called phthalocyanine, which was first developed in the 1920s. Phthalocyanine Blue is the original pigment distinction for pthalo blue, and because of this pigment, there is such an opacity in it. Pthalo blue lays on very thick!
Pthalo blue is a yellower blue
In the land of blue oil paints, pthalo blue falls onto the greener tinted side of blues. Be careful about applying this information to other mediums though! For example, in watercolors, there are different variations of pthalo blue (for red and greener options).
It is a popular choice for painting skies, water, and foliage, as well as for mixing with other colors to create a range of blues and greens.
It is more pigmented than it’s alternative
Since pthalo is greener, it falls into the same category as cerulean. However, pthalo is much thicker. When mixed with other colors, pthalo can overpower the other hues quickly. So, if you are looking for a mixing compatible alternative, cerulean should be what you get.
It creates more vibrant shades on the yellow side of the color wheel
Since it falls under a yellower blue, when mixed with its likenesses, it can really take off. For example, mixing it with green or yellow will illuminate the blue. Mixing it with a warmer color like red or purple will mute the color.
This is important to know based on what look you are achieving. If you need a red that is more muted, or a purple, pthalo can be great.
When using pthalo oil paint, it is recommended to use it in moderation and to mix it with other colors to avoid overwhelming the painting with its intensity.
Pthalo Blue vs Cerulean Blue oil paint (the two yellow tinted blues)
Pthalo is a bright, intense, and highly saturated blue pigment that has a strong tinting strength. It is very opaque.
Cerulean blue, on the other hand, is a softer, more subdued blue pigment that is often used for painting skies and water as well. It has a lower tinting strength than pthalo, which means it takes more paint to achieve the same level of intensity.
When it comes to choosing between pthalo and cerulean blue, it often depends on the artist’s personal preference and the desired effect they are trying to achieve. Pthalo is a better choice for artists who want a highly intense, vibrant blue color, while cerulean blue is a better choice for artists who want a more subtle, nuanced blue color.
So personally, I use cerulean mostly because of its mixing ability, but if I am painting a large full sky, I will use pthalo.
Additionally, cerulean blue is generally considered to be less toxic than pthalo. Which makes it a safer choice for artists who are concerned about the potential health risks associated with certain pigments.