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Pigments |
Classification | Quality | Hazards | Pearlescent Pigments | Food coloring | Resources
| Pigments classification and Quality |
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Pigments |
| Pigments classification and Quality |
Quality Variation of Pigments Dust The chemistry, the weight and the size of pigments are differents. One observe variations in volatily, absorbtion, chimical reactions, tranparency and permanancy. In general, natural colors are less permament than synthetic ones. Also some pigments are easy to grind while some others are difficult.
Permanency Color Test
Once you have got your collection of pigments, you should do a permanency color test. Take a canson paper and paint over sample horizontal lines for each color pigment you have. Use your usual Egg Tempera Emulsion (or your current medium, since that it may alterate the results). Split each line, in order to have the pure color in the up part and a mixed color with titanium white in the down part. Protect this painted canson paper with a blank paper to prevent light from alterating the colors. Each day or each week you will slide the top blank paper to the right and so unveil a new painted area to the light. For most obvious results, place this system under the sun in a protected area. Don't forget to write the lenght of time exposure for each vertical line. 1 week, 2 weeks etc. You will probably be surprise to observe that some of your colors completly desapeared. Take a note of it and put these pigments in the trash.
Hazards & Toxicity Egg Tempera Paint requires water as paint thinner. This is a big advantage compare to Oil Painting which requires the use of the toxic Turpentine causing allergies. On the other hand home made paint requires the manipulation of dry pigments which is highly hazardous due to the possibility of inhalating the dust. As Artists using dry pastels sticks, Egg Tempera painters are strongly exposed to such a hazard. Grinding or painting with dry powder pigments can be hazardous. This is a particular problem with highly toxic pigments.
For acute information refer to :
* Artist's Beware : The Hazards and Precautions in Working with Art and Craft Materials by Michael Mc Cann Watson-Guptill New York, 1979, ISBN 0-8230-0295-0.
* Center for Occupational Hazards, 5 Beekman Stret, New York, New York 10038 Phone (212) 227 6220Human carcinogens pigments
Lead pigments :
Chrome pigments : Chrome yellowlead chromate, zinc chromate,
Cadmium pigments :
Manganèse pigments :
Mercury pigments :
Arsenic pigments : Emerald green (Copper aceto-arsenite) is not lightproof, mixture with other several pigments will darken.
Recommandations for handling pigment dust ( Kremer: Safety Advice )
Set aside a special room, a place easy to clean where animals and children do not play. When manipulating dry pigments wear an approved dust mask, latex gloves and clean up all pigment powders with a wet paper towel or vacuum cleaner. Do not eat, drink or smoke in the studio.
Research for non toxic pigments
In 1995 Rhône-Poulenc chimists were experimenting non toxic pigments. Basicaly constituted of cerium sulfure they were able to produce non toxic pigments from gold yellow to red and were planing reel yellow and blues. Abstract from the french magazine "Science & Avenir" december 1995.
Recherches de pigments non toxiques
Les terres rares donnent le ton, extraits d'un article paru dans Science et Avenir de décembre 1995
" ... En 1995, ... les chimistes de Rhône-Poulenc ont mis au point des pigments minéraux rouges et orangés à base d'un mélange de terres rares. Le principal ingrédient de ce cocktail est le sulfure de cérium, dont la couleur rouge brique peut être modulée en variant la proportion des autres terres rares afin d'obtenir des pigments allant du jaune d'or au rouge sombre. Dispersés dans les matières plastiques, ces pigments demeurent stables jusqu'à 350°C, résistent aux UV ainsi qu'aux intempéries et peuvent entrer en contact avec des produits alimentaires. Les chimistes envisagent d'utiliser cette nouvelle technologie pour synthétiser d'autres couleurs, telles que le jaune ou le bleu."
Pearlescent Pigments Jacquard Pearl-Ex Mica Pigments or Mearlin Engelhard's pearlescent and iridescent luster pigments are quite anusual. Basicaly, they all have the same composition. The powder is made of micro mirors (mica platelets) coated with different thicknesses of some kind of transparent material (titanium dioxide and/or iron oxide). The light reflecting on each micro miror is difracted into a specific color depending on the thickness of the tranparent material. These pigments are nonmetallic, but metallic-like tones and iridescent color plays. They were designed for packaging, plastics incorporation, coatings and printing inks. Available in range of white pearls, nonmetallic, metallic-like tones and iridescent color plays. The New Micro Pearls interference type pigments with very fine average particle size provids increased coverage. They are environmentally safe, non-reactive powders, non-toxic, non-arcing and non-tarnishing for plastic incorporation ...
For Art painting, pearlescent pigments are interesting to over paint regular pigments. They enhance and give a special final tuch over clear and dark colors. It is probably better to use them with discretion. Nevertheless interesting anusual results can be achieved working with 100% of pearlescent pigments over a dark or black background support. Interesting gold effects can be obtained, but the general perception of this material is depending upon lighting exposure. The painting acts like a miror reflecting colored light rays resulting from light difraction.
Irridescents colors Hi-Lite
Gold 9220C, Red 9420C, Blue 9620C, Green 9820C, Violet 9520C, Orange 9320C
Majestic Gold 9222X, Aztec Gold 9363C, Mayan Gold 9233X, Inca gold 9222G, Brass 9222C, Super Brass 9232Z, Satin White 9130F, Silk White 9110WMetallic-like tones offering strong coloring
Copper 9340A, Super Russet 9450Z, Super Copper 9350Z, Super Bronze 9250Z, Golden Bronze 9240ANew York - New Jersey - Delaware - Engelhard Corporaation
101 Wood Avenue - Iselin - New Jersey 08830-0770
Marlene Smith, Customer Support
Phone: 800-321-3762; 732-205-6898 Fax: 732-205-6898 E-mail: marlene.smith@engelhard.comEurope and Middle East Engelhard Corporaation
96 Rue Saint Charles - 75015 Paris - France
Francois Defresne Industry Manager
Phone: 011-33-1-45-78-36-36 Fax: 011-33-1-45-78-36-38 E-mail: francois.defresne@mearlint.fr
Food coloring powder (non toxic but non permanent)
Food coloring powder are colorsless, they have to be put in contact with water before geting their true color. They are too much strong coloring, and so nearly impossible to balance with other colors. But their bigest defect is that they are non permanent and so can't be of any interest for serious working. Nevertheless their non toxic aspect is attractive for teaching egg Tempera to children. In that case to reduce its coloring power and cost, one can mix a certain proportion of plaster of Paris in each food coloring powder.
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