Calendula petals (dried)

David Fisher, The Complete Photo Guide to Soap Making (Creative Publishing International, 2018), p. 20: dyes "give a full range of hues—from subtle to bright and bold", but "can bleed between layers or swirls of soap, especially in melt-and-pour soap. Some are not stable in cold process soap, so test them first"; oxides "are very stable and strong in soap". Natural colours, pp. 82–84. In an infused oil: "Annatto: yellow-orange"; "Alkanet: light to deep purple, depending on the amount used"; "Paprika: orange-peach". In the lye solution: "Indigo: light to deep blue"; "Madder root: pinkish-red"; "Rose clay: deep rose pink". Added to the oils or at trace: "Activated charcoal: light gray to deep black"; "Black walnut hull (ground): speckled brown, also an exfoliant"; "Calendula flower petals (whole or ground): nice, warm yellow"; "Carrots (puréed or juiced): muted orange"; "Cinnamon: reddish tan to brown"; "Cocoa powder: tan to brown"; "Cucumber: pale yellow-green"; "Rosehips (ground): speckled reddish brown"; "Sage: muted green"; "Spirulina: pastel green/blue-green". For "a bright, white bar of soap": "Add titanium dioxide: about 1 teaspoon per 1 pound (454 g) of oils."

Bramble Berry, dried lavender, calendula and red rose petals: "Sprinkle on top of soap or mix the flowers into scrubs or bath salts. To infuse, heat the flowers and the oil of your choice in a slow cooker for 1 to 4 hours or place in an airtight container and leave at room temperature for 4 to 6 weeks. A general usage rate is about 1 tablespoon per pound of oil."

Anne-Marie Faiola, Soap Crafting (Storey, 2013): lavender buds sprinkled on top (p. 114): "some of the buds will sink into the soap a bit, and you want a layer to stay on top. Don’t spray with alcohol as it makes the herbs soggy"; Calendula Cleansing Bar (p. 158), 0.5–0.8 oz of calendula petals, about a cup, 0.3 oz of it infused in oil and the rest stirred in or pressed on top.

David Fisher, The Complete Photo Guide to Soap Making (Creative Publishing International, 2018), p. 19: exfoliants, "Start with 1 to 2 teaspoons per 1 pound (454 g) of oils or soap base"; calendula petals "retain their yellow color nicely"; coffee grounds, "scrubbiness is determined by the coffee’s grind"; "Citrus peel (dried and ground): offers a medium scrub; add at trace"; cornmeal, "medium scrub; premix with oil and add at trace"; eucalyptus leaves, "a medium scrub, especially if not very finely ground"; lavender buds "will turn brown in cold process soap and look like mouse droppings; gently grind them first to avoid this"; loofah, "light to medium scrub"; mint is "prone to bleeding; steep as a tea first"; oatmeal, "like coffee, the scrubbiness is determined by how ground it is"; poppy seeds, "light to medium scrub"; pumice, "heavy-duty scrub; great for mechanic’s or gardener’s hand soaps"; rose hips, "medium to high scrub; also adds natural color"; rose petals "turn black in cold process soap"; sandalwood powder "gives a medium to high scrub, and makes a lovely purple color"; "ground stone fruit pits (apricots, peaches) and berry seeds (ground or whole) give a medium to high scrub factor"; walnut shells, "a nice medium scrub and a lovely medium brown color".

Alicia Grosso, The Everything Soapmaking Book, 3rd edition (Adams Media, 2013), chapter 13: "Yarrow (Achillea millefolium): Dried and fresh flowers and leaves release a bright yellow dye into boiling water, lye infusion, and in oil"; "Bamboo sap powder is a gentle and thorough exfoliator, but it is best to start with 1 teaspoon bamboo sap powder per pound of oils"; cocoa powder, "in high concentrations it will produce brown lather"; calendula for a sun-infused oil, "Use about 3 tablespoons of petals per pound of oil".

Lovely Greens, herbs and dried flowers in soap: "I tend to use 1-3 tsp of plant material per pound (454 g) of soap. One teaspoon for dense material, like poppy seeds, and three teaspoons for fluffier herbs, like calendula petals"; "Calendula flower petals don’t discolor in soap recipes"; "rose petals will turn rusty brown wherever they touch soap, and almost every herb turns dark brown when mixed in"; lavender, "Inside the soap, the buds turn brown"; "most fruit and vegetable juices or purees will turn your soap brown or fade to an unexciting tan or yellow"; "Botanicals can soften, mold, and rot if kept in moist or humid places"; "Too many dried seeds or herbs stirred in can feel scratchy or stop the soap from lathering properly".

Elizabeth Letcavage and Melissa Harden, Natural Soap Making (Stackpole Books, 2013): calendula "is the only flower that will keep its yellow color through the saponification process. Other flowers ... will turn brown or black"; "Lavender flowers will have a nicer appearance in soap if they are slightly ground"; light additives "(such as seeds, grains, or lavender flower buds)" are added at "heavy trace" to stay suspended; "Leaves of herbs such as mint, nettle leaf, and lemon balm are dried before use"; "Ground Nettle Leaf 2–3 teaspoons", "Ground Oats ¼ cup" and "Ground Cornmeal ¼ cup" in recipes of 48 oz of oils, added at light trace; the Basic Three-Oil Soap, 48 oz of oils, takes "½ cup ground oats or other additive".

David Fisher, The Complete Photo Guide to Soap Making (Creative Publishing International, 2018), p. 86: "most all flower petals, except calendula, will turn black when they come into contact with lye"; "Herbs such as rosemary, leaves such as eucalyptus and patchouli, citrus peels, ground rose hips, and teas such as spearmint and peppermint, can all be used to make beautiful soaps. But, like flower petals, they turn brown or black. Most dried leaves, especially rosemary and eucalyptus, need to be ground finely or they can be too scratchy".

E. Paulsen, "Contact sensitization from Compositae-containing herbal remedies and cosmetics", Contact Dermatitis 47 (2002) 189–198: species "including ... German and Roman chamomile (Chamomilla recutita and Chamaemelum nobile), marigold (Calendula officinalis) ... have been suspected of sensitization or elicitation of Compositae dermatitis"; sensitisation "occurs rarely with the majority, especially the widely used German chamomile".

Calendula petals by volume: 44 cups a pound, 0.044 g/mL (Voyageur Soap & Candle); "0.3 ounces of dried calendula petals (about 1/3 cup by volume)", 0.108 g/mL, and "0.5–0.8 ounce ... (about 1 cup by volume)" (Faiola, Soap Crafting, Storey, 2013, p. 159–161). Petals pack loosely or tightly; the spread is that.