Manufacturers list both Ivory Black and Mars Black as opaque. If you use either black at full strength, it should cover over any existing color with one coat. All of the black pigments made by Liquitex and Golden are listed as opaque on their color charts.
If you’re looking for a more transparent black you have a few options. When working with acrylics you can mix the black with an acrylic medium such as gloss medium, matte medium, or glazing medium. There are also gel mediums.
Another option is to dilute the acrylic paint with water to make it more transparent. You don’t want to add more than 25-30% water to acrylic paint because it dilutes the binder. If you’re working on paper, you can add more because the paint absorbs into the fibers of the paper.
Another option for creating a transparent black is to mix your own black from transparent colors. My post, 11 ways to mix black covers this in detail. You can mix Phthalo Blue with Quinacridone Magenta to make a dark blueish purple. Then you need to add a transparent yellow, such as Hansa Yellow Medium, to neutralize the blueish purple. Add small amounts at a time until it turns black. My acrylic color mixing demo has a video where I mix black from these colors.
A Comparison of the Tinting Strength of Mars Black and Ivory Black
The tinting strength of a pigment is its ability to alter the appearance of a color mixture. For instance, Phthalo Blue has a high tinting strength. You only need to add a small amount of it to influence another color. A small dab of Phthalo Blue will tint a larger volume of white.
Mars Black has a reputation for having a higher tinting strength than Ivory Black. Below is tinting strength experiment where I measure out equal amounts of each black and white and mix them. I measure the dabs of paint by eye. It would be more accurate to use measure them with a beaker or measuring spoon. However, that kind of precision is unnecessary because the tinting strength of Mars Black is very obvious. A small amount of Mars Black will create a substantially darker gray than the same amount of Ivory Black.
At the top left are dabs of Ivory Black and Titanium White, which creates the gray below it. I repeated the same experiment by mixing Mars Black with Titanium White. The Mars Black creates a much darker gray which means it has greater tinting strength.
How does the tinting strength of each color impact your painting? You have to develop a sense of the tinting strength of the colors you use. This knowledge will help you to better approximate how much of each color you have to add to mix the color you want to create. If you’re unaware of the tinting strength of each color, then you may end up wasting paint.
One way to deal with colors that have strong tinting strength is to premix a weaker version of it. For example, If you need to mix a large variety of subtle grays, you can premix a middle gray from Mars Black and Titanium White. Then you can use the middle gray to mix the subtle grays. This should be easier than using the Mars Black straight from the tube.
What is Ivory Black Made From?
Ivory Black was historically made from ivory. While it’s no longer being made from elephant tusks, most manufacturers do use charred animal bones to make Ivory Black. There are other black paints that don’t contain animal products. Carbon Black, Lamp Black, and Mars Black are good candidates. Check with the manufacturer to be sure.
What Is Chromatic Black?
Chromatic black is black that you can mix from other colors. You can mix Ultramarine Blue with Burnt Umber to make black, for instance. Technically speaking, these are “mixing complements” which aren’t always the same as the complementary colors found opposite of each other on a color wheel. There are flaws with most color wheels, so you don’t want to rely on them to find colors you can mix to create black.
Some manufacturers offer a chromatic black in a tube. This may interest you if you want to save time and don’t want to mix your own chromatic black. Gamblin offers a chromatic black in oils. M Graham also has Chroma Black which is a mixture of Ultramarine Blue and Burnt Sienna. I list these color in the table at the top of the post.
It’s surprising how many options there are for mixing your own black. I came up with 11 ways to mix black, just from the colors that I had in my studio. There are probably other combinations that work too.
Will Black Paint Fade?
The Mars Black and Ivory Black from Liquitex have a lightfastness rating of I. This means that it has the highest lightfastness rating so it shouldn’t fade. Golden also lists their Mars Black and Carbon Black as having excellent lightfastness ratings. Most black pigments in artist quality paints have a excellent resistance to fading.
Is Mars Black Magnetic?
A fun fact about Mars Black is the iron pigment that it contains makes it attractive to magnets. Obviously, it’s the magnet that has magnetic properties, while the paint contains metal particles that attract the magnet. A magnet will stick to the tube if you hold it up to it as shown in the photo below. The tube is made from plastic and the magnet won’t stick to a tube of Liquitex Ivory Black.