How To Make Phthalo Blue From Ultramarine
Artists often wonder how to make phthalo blue from ultramarine, since both pigments belong to the family of strong and versatile blues. Phthalo blue is known for its intensity, transparency, and slightly greenish undertone, while ultramarine has a warmer, more violet hue. When working with a limited palette or experimenting with color mixing, learning how to adjust ultramarine blue so that it resembles phthalo blue can expand artistic possibilities. Although they are chemically different pigments, careful mixing with complementary colors allows artists to simulate the qualities of phthalo blue using ultramarine as a base.
Understanding Ultramarine and Phthalo Blue
Before attempting to create one from the other, it is important to understand the nature of these colors. Ultramarine blue is a deep, rich pigment that leans toward violet. It has been prized since ancient times for its luminous quality, originally derived from the semi-precious stone lapis lazuli. Modern ultramarine pigments are synthetic but retain the same warm character. Phthalo blue, on the other hand, is a modern pigment introduced in the 20th century, famous for its strong tinting strength, transparency, and greenish undertone. It is often described as colder and more intense compared to ultramarine.
Key Differences Between the Two
- UndertoneUltramarine leans violet, while phthalo leans green.
- TransparencyPhthalo is more transparent, ultramarine is semi-transparent.
- Tinting StrengthPhthalo is highly concentrated, ultramarine is gentler in mixes.
- Mixing BehaviorUltramarine can soften other colors, while phthalo intensifies them.
Why Artists Try to Recreate Phthalo Blue
Phthalo blue is popular for glazing, vibrant skies, and mixing bright greens. However, not every painter has it in their palette. In situations where ultramarine is available but phthalo is not, simulating phthalo through mixing becomes useful. While you cannot change ultramarine’s chemical composition, you can shift its tone and transparency to mimic the look and behavior of phthalo blue in practice.
Color Mixing Basics
To make ultramarine behave like phthalo blue, the key lies in neutralizing its violet bias and enhancing its greenish qualities. This means mixing ultramarine with small amounts of other colors until the desired effect is achieved. Artists commonly use green pigments, turquoise shades, or primary colors to adjust undertones.
Mixing Tools You Might Need
- A palette knife for clean blending
- A mixing palette or surface
- Test paper or canvas for swatches
- Ultramarine blue paint as the base pigment
- Additional pigments like phthalo green, cerulean blue, or even lemon yellow
Methods to Shift Ultramarine Toward Phthalo
Method 1 Ultramarine + Phthalo Green
The most effective way to mimic phthalo blue is to mix ultramarine with phthalo green. Since phthalo green has a strong cool undertone, it balances the violet of ultramarine and shifts it toward the greenish character of phthalo blue. Start with ultramarine as the dominant color and gradually add tiny amounts of phthalo green until the mixture resembles phthalo blue.
Method 2 Ultramarine + Cerulean Blue
Cerulean blue is a cooler, slightly greenish blue. Mixing ultramarine with cerulean can help push ultramarine’s violet tone closer to the cooler, greener spectrum of phthalo. While it may not achieve the same intensity, this mixture produces a workable substitute that behaves similarly in mixtures, especially when creating natural greens.
Method 3 Ultramarine + Lemon Yellow
If phthalo green or cerulean blue is not available, lemon yellow can be used. Adding a very small amount of a cool yellow to ultramarine neutralizes its violet undertone, creating a bluer and cooler hue. This mixture must be handled carefully, as too much yellow will turn the color green instead of maintaining its blue base.
Method 4 Ultramarine + Viridian Green
Viridian is another green pigment that works well in adjusting ultramarine. Though not as intense as phthalo green, viridian can still neutralize the warmth of ultramarine and shift it toward a cooler, greener blue. This mixture produces a softer version of phthalo blue, which can be useful for landscapes and natural tones.
Practical Applications in Painting
Once you have mixed ultramarine into a phthalo-like shade, test it in different contexts. For skies, thin the mixture with white to see how it tints. For greens, blend it with yellows to test vibrancy. For glazing, try applying transparent layers to observe its luminosity. Adjust proportions of the mixture as needed until the substitute behaves closely to phthalo in different scenarios.
Testing with White
Mixing the phthalo substitute with titanium white helps reveal undertones. If the mixture appears too violet, add more green. If it appears too green, balance it with additional ultramarine. Testing with white ensures you see how the color behaves in highlights and lighter mixes.
Mixing Greens
One of the strengths of phthalo blue is producing vibrant greens. Test your ultramarine-based substitute by mixing it with lemon yellow or cadmium yellow light. If the green appears dull, add more of the green pigment (such as phthalo green) to your original mixture to increase intensity.
Advantages of Mixing Your Own Substitute
- Expands your color mixing skills
- Reduces the need for extra tubes of paint
- Gives more control over hue adjustments
- Allows experimentation with unique variations
- Improves understanding of undertones and pigment behavior
Limitations to Keep in Mind
It is important to remember that no mixture will perfectly replicate the chemical properties of phthalo blue. Ultramarine mixtures can mimic the hue, but phthalo’s extreme tinting strength and transparency are difficult to duplicate exactly. For professional work requiring consistent results, using actual phthalo blue may still be necessary. However, for practice, sketching, or when supplies are limited, these mixtures are effective alternatives.
Tips for Successful Color Mixing
- Always start with small amounts of secondary pigments to avoid overpowering ultramarine.
- Use a palette knife instead of brushes to achieve cleaner mixes.
- Test mixtures under natural light to see true undertones.
- Keep swatches of your mixtures for future reference.
- Practice layering to achieve the transparent qualities associated with phthalo blue.
Learning how to make phthalo blue from ultramarine is a valuable exercise for any painter seeking to expand their palette without purchasing additional pigments. By mixing ultramarine with greenish or cooler pigments such as phthalo green, cerulean blue, lemon yellow, or viridian, you can shift its undertone and mimic the vibrancy of phthalo blue. While the result may not be a perfect match, it allows artists to explore color theory, refine mixing techniques, and create a versatile substitute. This process highlights the beauty of experimentation in art, proving that with the right knowledge and practice, even a warm violet-blue like ultramarine can be transformed into a convincing stand-in for the brilliant coolness of phthalo blue.