A discussion on adding pigments to cement products: Grout, Cement-based Adhesive (Thinset), and Poured Cement
Rainbow Colorants by Karen Sasine are incredibly intense. This gives the user the ability to make an almost infinite array of colours (truly a Rainbow) without compromising the quality of their grout (regardless of brand).
Remember, you can only add a maximum of 10% pigment to your cement product (grout, adhesive or Self-Levelling cement) without compromising cement strength.
The most intense colours are made if your mix is on the drier side.
To get the most out of these pigments, I recommend mixing up a number of colours at full strength (use my FREE Mixing Calculator), and then mixing the colours to suit your needs.
I’ve listed a few of the colour recipes I’ve used as a starting guide.
Colour Recipes
Flesh tones:
- Base: Use Hesperidium Orange (or a mix of Yellow and Red)
- Neutralise: Mix in a VERY SMALL amount of the Complementary Colour – Blue, or a blue-green, such as Green (Aqua) SB66. This should create a brown or Peach shade
- Adjust Value: Use Snow to lighten the mix for fair skin tones
- Adjust Warmth: Add tiny amounts of Magenta GT to increase warmth, or Yellow
Mauve:
- Base: Use Plum. This is a very intense purple
- Adjust Value: Use Snow to lighten the mix to create a lavender or violet. Because Plum is so very dark, you need to do this step first, before neutralising the shade.
- Neutralise: Mix in a VERY SMALL amount of the Complementary Colour – Green HP. This should cut the brightness
Chartreuse:
- Base: Yellow YG88
- Neutralise: Add Lemon-lime to add in the green element. Note: Yellow and Green are next to each other on the Colour Wheel
- Adjust Value: Use Snow to decrease intensity
Grey: an often underused colour, grey is very versatile. Greys can be Warm or Cool.
- A Warm Grey can be made on a Latte base, with the addition of small amounts of Black Oxide 451
- A Cool Grey can be made on a base of Snow, with the addition of VERY small amounts of Black BK555.
- You can then tone the result with small amounts of Green, Blue or Red
Lightening Colours
My Mixing Calculator works on maximum loads. The picture below shows what happens to Cobalt Teal when the quantity of pigment is reduced in a white base.
Lightening colours can easily be achieved by decreasing the intensity of pigment you add, or adding some Snow pigment.
Some examples of colours that can be achieved:
- Magenta GT: can product wonderful pinks – candy pink, rose pink, etc
- Blue 6719 (Sky): Adding white will make a wonderful set of blues. Remember, skies are lightest at the horizon.
Darkening Colours
Black BK555 is a wonderful pigment to create rich deep colours:
- Burgundy – Magenta GT with a touch of BK555
- Emerald Green – Lemon-Lime with a touch of BK555
- Deep Teal – Green SB66 (Aqua) with a touch of BK555
- Chocolate – Brick (extra warmth) with a touch of BK555
Another approach to developing moody colours is to use a mid-dark grey as your base (I recommend Litokol StyleGrout Tech in Dark Silver). See the example below – again using Cobalt Teal
Mixing more than 2 colours
You can mix as many colours as you need to achieve the end colour, but do so carefully. Adding too many colours will risk ending up with a murky brown.
Always start with a base colour, and use other colours to adjust.
Peach: Is basically pink (magenta and white), with a touch of Yellow (note the Yellow 3776 is a good mixing yellow for this). If the result is too dark, you can reduce intensity by adding Snow.
Salmon: very similar to Peach, but warmer – more pink, and you could add Buff or Golden instead of the Yellow. Adjust intensity by adding snow
A word on Colour Temperature:
You may have heard colours referred to as either “warm” or “cool”. Well what does this really mean?
- Warm Colours: Tend to be more aggressive or dominant. Reds, oranges and yellows. To darken while keeping the warmth, use Black Oxide 451 (not as powerful as BK555)
- Cool Colours: Recede – these make wonderful backgrounds. Greens, Blues and violets. Can be darkened with SMALL amounts of BK555.
The colour wheel is split equally between warm and cool colours. Every complementary pair (colours opposite each other on the wheel) is made up of a warm and a cool colour.
I do recommend that you purchase a Colour wheel. They are invaluable in understanding colour theory – the relationship between colours, and why some work and some don’t. The one I like is published by the Color Wheel Company (US) and is available from good art supply stores.
General discussion on Colouring Cement (for the Nerds)
Concrete is composed of two main ingredients, cement paste and a sand/aggregate. When colouring cement products, the objective is to keep the pigment particles attached to the binder (cement) – the “glue” keeping everything together. If excess water is present when making concrete, a weaker link between pigment and binder is formed. The amount of water added when mixing cement products should only be enough to chemically convert 100% of the cement. Excess water is why concrete cracks, degrades and falls apart over time.
Also, the higher the water content, the lighter the colour and the weaker the cement paste. Why does more water create a lighter colour? In mixing, tiny air bubbles are created, scattering the light and giving the appearance of a lighter colour. The objective should always be to use as little water as possible when making any concrete.
The cement must be covered with pigment particles to shift the cement colour in various directions. It is that simple. The more we cover up the cement binder surface colour with pigment particles, whether grey or white cement, the more saturated the colour becomes. Look at the colour of the pigment powder itself. In general, this shows what a maximum loading will look like. Some pigments can be added at loadings up to 10% to reach this saturation stage. Other pigments achieve full saturation at 3.0% (such as Plum). These are the maximum loads listed for each pigment.
The key parameter is the desired final target colour – this determines which combination of pigments are required.
The following tips will save you time and effort when working with pigments:
- The difference in colour between a 1% loading and a 2% loading is greater than the difference between a 5% loading and a 6% loading. Why? Because at a 2% loading you have twice as much pigment as a 1% loading. However a 6% loading is only 20% (1/5th) more pigment than a 5% loading.
- Rainbow Colorants Black BK555 is a game changer to create very dark concrete colours. Whilst the Rainbow Colorant Black Iron Oxide 451 at an 8.0% loading is a nice deep grey colour it will not easily deepen colours because the higher saturation leaves little room to add other pigments. BK555 at 3.0% is far darker than Black Iron Oxide at higher concentrations.
- Very small amounts of water are needed to chemically convert cement particles, usually a Water/Cement ratio of 0.32 or less. Excess water is the enemy of high performance concrete and the resulting concrete strength is always weaker. And this excess water washes out and lightens all pigments and creates efflorescence. Grout additives can aid in reducing the excess water amounts thus improving concrete strength AND producing richer and more vibrant colours. (NOTE: additives are not required when working with enhanced grouts such as Litokol StyleGrout Tech)
- Water is required to chemically convert cement powder into a complex crystal lattice multi silicate structure. BUT only enough water should be added to accomplish this chemical reaction. Water is H20 and both H and O are required to chemically convert cement into the silicate structure. Adding more water to create flow or to improve compaction is very common, however it is the absolute worst thing to do from a chemical point of view.
Rainbow Colorants
Rainbow Colorants have been developed by a world leading concrete pigment expert, with over 42 years in the pigment industry.
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