Black walnut hull powder

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."

Lovely Greens, natural soap colorants: cinnamon, "use up to 1 tsp ground cinnamon powder PPO. Be aware that cinnamon leaves a slightly gritty feeling"; beetroot, "Warm to dull brown", "Unfortunately, beets do not color CP/HP soap red"; black walnut hull powder, "Add powder at trace and be aware that they create a scratchy or exfoliating texture"; red sandalwood, "Add 1/4-1/2 tsp powder PPO at trace after premixing in a little oil. Can be very scratchy if you use more than this"; woad, "Add 1-2 tsp powder PPO to the lye solution"; rose hips, "Up to 1 tsp ground rosehip powder PPO"; nettle leaf, "muted green", "Premix dried and powdered nettle leaf with a little water and add at trace. Use 1-3 tsp PPO"; kelp, "Dark green", "at trace at up to 3 tsp PPO. Pre-mix in an equal amount of distilled water"; sage, "muted green that fades with time", or "1 tsp PPO dried sage at trace for dark speckles"; peppermint, "1 tsp PPO finely ground peppermint leaves at trace"; liquid chlorophyll, "stunning greens from using about 1 TBSP PPO", fading "into a greeny-yellow"; cucumber, "initially green but usually fades to a muted yellow"; chamomile, "Infuse flowers in distilled water and use the strained liquid to make the lye solution"; green tea, "Brown-green"; rhassoul clay, "Brown"; French green clay, "pale pastel green to earthy green"; "plant-based greens tend to be fugitive". PPO is per pound of oils.

Wholesale Supplies Plus, beet root, black walnut and chamomile powders, and green zeolite and sea clays: "Common use levels are 1 teaspoon to 1 tablespoon per pound of base"; for the beet root and black walnut powders, "Test your final product to insure optimal performance and no staining."

EU: Regulation (EC) No 1223/2009, Article 14(1)(c), a product may contain as colourants only those in Annex IV. US: 21 CFR Part 73 Subpart C lists the colour additives for cosmetics, and turmeric, paprika and spirulina are listed for food only; under 21 CFR 701.20 a true soap, sold only as soap, is not a cosmetic.

Voyageur Soap & Candle, botanical product pages, "Approx. Cups/ Lb": lavender flowers 17; calendula petals 44; chamomile flowers, whole, 21; red and pink rose petals and buds 22; peppermint leaf, cut and sifted, 15; eucalyptus leaf, cut and sifted, 7; sage, ground, 8; kelp powder (Ascophyllum nodosum) 3; black walnut hulls powder 4. Peppermint and eucalyptus leaves "can be sprinkled into the soap mixture when at a light trace to create a speckled effect"; comfrey leaf goes "into the lye water to create even color distribution which produces a natural green bar, or sprinkle it into the soap mixture when at a light trace". Density = 453.6 g ÷ (cups × 236.6 mL).