Quinacridone Magenta is a semi-transparent and powerful bluish red with an impressive mixing range. It makes an excellent glazing color and is one of the bluest of the Quinacridone colors. The pigment's properties vary considerably, depending on how it is ground. Quinacridone pigments have relatively low tinting strength in general. For this reason, quinacridone colors are often expensive, because more pigment is required in the formulation.
Quinacridone Magenta offers very good lightfastness in most media, but some have argued that it is less lightfast in watercolor form. Although Quinacridone Magenta received only a passing grade of "fair" under ASTM test protocols, other test results have rated the pigment very good to excellent. Transparent reddish violet pigments in general have more problems with lightfastness than any other range of colors. PR122 is often used as the Magenta of CMYK (four color) process printing because it offers a better tradeoff between tinting strength and lightfastness than other pigments in its class.
Quinacridone Magenta has no acute hazards. Overexposure to quinacridone pigments may cause skin irritation. Quinicridone pigments contain a compound found to be a skin, eye, and respiratory irritant.
Quinacridone Magenta came from a red violet aniline dye that was first produced in 1858 by Natanson. It was called Magenta to commemorate a battle in Magenta, Italy. Over time, Magenta became the standard color name for a deep, violet red. Although quinacridone compounds became known in the late 19th century, methods of manufacturing so as to make them practical for use as commercial pigments did not begin until the 1950s. PR122 has become particularly popular in the formulation of Magenta for CMYK process printing.
Calcium carbonate, the mineral constituent of chalk, is a low tinting strength, inexpensive white pigment that is often used is a buffer and filler. Because of its low tinting strength, it is overwhelmed by other colors. It is used in gesso and other coatings to give the surface more tooth, a desirable characteristic for some painting techniques.
Calcium carbonate is lightfast. Like all carbonates, it reacts with strong acids
Calcium carbonate is completely non-toxic, and is used in many food, cosmetic, and pharmaceutical products. However, excessive consumption is not recommended.
Naturally occuring chalk deposits have been mined since prehistoric times. Rocks and minerals that contain calcium carbonate include aragonite, calcite, vaterite, chalk, limestone. marble, and travertine. Calcium carbonate is the principle component of lime, used in many agricultural and industrial applications.
Burnt Sienna is a warm, mid-brown color formed by burning the yellow-brown limonite clay called Raw Sienna. It ranges from semi-opaque to semi-transparent due to the combination of its opaque, red-brown mass tone and its transparent, orangey undertone. It is an excellent mixing complement for blues and greens and creates salmon or peach colored tints when mixed with white. It can be useful for subduing bright colors and does not get chalky in dark mixtures.
Burnt Sienna has good permanence and is considered one of the most versatile of the permanent pigments.
Burnt Sienna has no significant hazards.
Burnt Sienna has been used as a pigment since prehistoric times, but its current name came about during the Renaissance. It comes from the city of Siena, in Italy, and is short for terra di Siena, meaning earth of Siena. Sienna was famous for the mining and production of earth pigments from the Renaissance until World War II. Due to the depletion of clay deposits in Tuscany, Italian siennas now come from other areas, including Sicily and Sardinia.