Extenders Set

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The Extenders Set contain sixteen different extender pigments in a boxed set that is an excellent introduction to making your own grounds and mediums, especially useful for exploring the function and behavior of different fillers in grounds.


The Extenders Set contain sixteen extender pigments in a boxed set that is an excellent introduction to making your own grounds and mediums and as a great gift for the art student. The set is especially useful for exploring the function and behavior of different fillers in painting mediums.

You will spend $20.00 more when you buy these pigments separetely 

Sixteen natural minerals are included in this set to introduce you to extender pigments and their function in grounds and painting mediums. The set includes 4 vol oz. jars each of:

Set Contents
Bologna Chalk

A natural mineral imported from Bologna, Italy composed of monoclinic prismatic crystals of hydrated calcium sulfate-carbonate. Gesso Oro per Indoratori is quarried and processed in Colle Val d'Elsa, the birth place of Cennino Cennini, in the same locale where he obtained his gesso for "gesso sottile." Gesso (Italian for gypsum) was used since before the Renaissance and mixed with animal collagen glue size to prepare wood panels and frames for painting and to adhere gold leaf.

TalcOur talc is dry ground from natural ores in Montana. Use as an additive to make grounds and for adding texture and body to paints.
Chalk (Calcite)The finest whiting for making brilliant white chalk grounds. Our whiting is dry ground from limestone deposits in the Lucerne Valley, California. Dry grinding limestone reduces it to a powder without destroying its particle structure, which is important in making strong chalk grounds and providing tooth on the surface of the grounds. The larger particle size of our chalk (when compared to precipitated chalk) keeps oil absorption low, which is ideal when adding it to oil paint and mediums. In painting grounds it makes a durable surface with tooth for egg and casein tempera, distemper, encaustic and oil paint.
Clear Glass PowderClear glass powder made from leaded crystal glass and ground into fine powder can be used in all media to give colors added luminosity or to create textural effects on the surface of paintings. Fine: Finer than 63 μ
Aluminum Trihydrate (ATH)Aluminum trihydrate is a filler, extender and bodying agent in oil- and water-borne paint that does not greatly affect the color of the paint. This is an 8 micron median particle size extender that is a bright white powder.
Kaolinite, CalcinedKaolinite is a clay mineral, also known as China clay or kaolin. Calcined kaolin clay is used as a functional extender in paint. Kaolin clay is also used in grounds, such as for painting and gilding.
PerlitePerlite is a amorphous volcanic glass that is processed so that it is greatly expanded and white. It can be used in painting grounds and to increase the bulk and give texture to paint.
Mica (Wet Ground)Our muscovite mica is a wet ground mineral used for applications requiring greater resistance to moisture, heat, light or chemicals and to add decorative effects, such as pearlescence.

Alabaster (also called satin spar) is a natural crystalline mineral of hydrated calcium sulfate mined near Volterra (between Florence and Sienna), Italy. Softer than chalk (3 Mohs scale of mineral hardness), its hardness of 1.5 to 2 makes a soft white gesso that is easier to polish to a smooth finish for gilding bases and painting grounds. Calcite or chalk, being a carbonate, effervesces on exposure to acids, whereas gypsum alabaster, when so treated, remains practically unaffected.Recommended in Cennino Cennini's treatise on painting, Il libro dell'arte (often translated as The Craftsman's Handbook), to make "gesso sottile" for painting grounds.Add to oil colors and mediums as a transparent filler and to give body or in tempera as a white filler.

Marble dustMedium, Fine and Extra Fine marble dust. Free-flowing, dry ground marble from natural calcite deposits with a controlled particle size. Use this marble powder to make grounds and for adding texture and body to paint.
BariteThis is a highest quality white, natural barium sulfate ore. Its unique properties of fine grind (3 micron median particle size), high specific gravity (4.4) and chemical inertness make it ideal for grounds, to make white paint and as paint filler.
SilicaThis is a high purity, natural crystalline silica that comes from quartz quarries in Oklahoma. It is a fine ground silica sand that is inherently inert, white, bright, and is at least 99.2% silicon dioxide. Special processing assures a controlled particle size distribution, which eliminates excessively coarse and fine particles. These properties, combined with its inertness and low cost, make silica an excellent filler and extender for paint.
Nepheline SyeniteExtra Fine Nepheline syenite is a micronized functional filler and extender used as a performance enhancer in a broad range of paints, coatings, adhesives, sealants, and inks. Excellent brightness, tint retention, and weatherability can be achieved in paints. Improved color, sheen uniformity, chemical and stain resistance, and durability result when it is used in interior paint formulations. It is easily dispersed in all conventional vehicle systems, and low oil absorption permits high loadings in adhesives, sealants, and aqueous and alkyd-based paints.
WollastoniteExtra Fine Wollastonite is a calcium metasilicate mineral that exhibits lower viscosity in paint than is indicated by its oil absorption value. The low oil absorption characteristic of wollastonite enables you to reduce raw material cost by replacement of the vehicle. The relatively high pH (10–11) of wollastonite is particularly useful in maintaining the desired alkaline pH level of water-based paints and preventing early rusting of water-based coatings. Wollastonite is an excellent extender pigment for powder coatings as well as solvent-based and waterborne paints.
More Information
BrandRublev Colours
VendorRublev Colours
Processing TimeUsually ships the next business day.
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