# Understanding the trichromatic recipe (Y:R:B and % owf) - URL: https://abdohoo.app/help/shadecard/trichromatic-recipe-explained - Product: Shadecard (https://sc.abdohoo.app) - Section: Recipes & the dyeing calculator - Updated: 2026-09-30 > A Shadecard recipe has two dials: the Y:R:B ratio sets the hue, the % owf sets how deep. Choose the fibre on the result to see the dye class; confirm everything with a lab dip. A Shadecard **Starting recipe** is written as a ratio of three primary dyes – **Y**ellow, **R**ed and **B**lue – plus a depth in **% owf** (grams of dye per 100 g of fabric). The ratio decides the hue; the depth decides how pale or deep that hue comes out. Together with the fibre you choose, that is enough to weigh out a first lab dip. ## The ratio sets the hue **Y 56 · R 16 · B 28** means that of all the dye you use, 56 parts are yellow, 16 red and 28 blue. The coloured bar under the numbers shows the same split. Mixing a yellow, a red and a blue in different proportions reaches most practical shades: - **Mostly yellow and red** → oranges, rusts, golds. - **Mostly red and blue** → purples, plums, maroons. - **Mostly yellow and blue** → greens, olives, teals. - **All three in balance** → browns, greys, taupes and near-blacks. The smallest component usually acts as the **complement** that dulls (saddens) the colour. The olive above is yellow and blue with a touch of red to mute it. ![Olive shade page: starting recipe Y 56 · R 16 · B 28 with depth medium (suggest ~1.5% owf), visually similar shades, and the Open in recipe calculator and Submit instrument reading buttons](https://abdohoo.app/media/library/shadecard/android-shade-detail-actions.webp)A starting recipe on a shade page, one tap from the calculator## The depth sets how deep The same ratio at 0.3% owf gives a pastel; at 3% owf it gives a dark shade of the same hue. On a result, Shadecard estimates depth from your fabric's measured lightness (L\*) and writes it out, for example *Use about 1.5% of the fabric's weight in dye — a "medium" depth for how dark your fabric reads.* The bands the app uses are pastel (0.1–0.5%), light (0.5–1%), medium (1–2%), dark (2–4%) and very dark (4–8% and more). These are indicative: a strong dye reaches a depth with less, a weak one needs more, and fibres take dye differently. Library pages show a shade's typical depth as *suggest ~x% owf*; a result uses your own fabric's L\* instead. ## Fibre and dye class The camera cannot see what the cloth is made of, but the fibre decides the chemistry. On the result, under **Fiber & dye type**, choose the fibre from the care label: Fibre chipDye class shownExample set the app lists**Cotton / viscose / linen**Reactive (default) · direct · vatC.I. Reactive Yellow 145 · Red 195 · Blue 19**Wool / silk**Acid · metal-complexC.I. Acid Yellow 49 · Red 249 · Blue 62**Nylon**Acid · disperseas wool/silk**Polyester**Disperse (130 °C HT)C.I. Disperse Yellow 54 · Red 60 · Blue 56**Acrylic**Basic / cationicC.I. Basic Yellow 28 · Red 46 · Blue 41**Blend**Two-class union dyeing– (advanced; get the fibre split from the care label)The example sets are common trichromats, not a recommendation: use three dyes that your supplier sells as compatible for that class, so they exhaust and fix at similar rates. The ratio itself travels between classes as a starting point; the lab dip with your own dyes shows how far it needs correcting. ## Tuning tips: which way to nudge When your fabric is not exactly on the shade, the result adds **Tuning tips** such as: - *Your fabric is warmer and yellower — nudge the yellow up a point or two.* - *Your fabric is more muted than \[shade\] — sadden the recipe with a touch of the complement.* - *Your fabric is cleaner and brighter — reduce the complement (the smallest component in the ratio).* They point the direction for your first correction; they are not spectral calculations. ## Your dip history After you have logged lab dips for a dye class and shade family (at least three), the result can adjust the recipe to how your process actually behaves and shows *Adjusted from your last n dips…*. A switch labelled **Use my dip history** turns this off to show the untouched library recipe. See [From recipe to lab dip](https://abdohoo.app/help/shadecard/from-recipe-to-lab-dip). Library colours are illustrative, not measured from dyed swatches, and every dye range, water supply and machine behaves differently. A Shadecard recipe is a hypothesis for your first lab dip, never a production recipe. ## Related - [Use the recipe calculator](https://abdohoo.app/help/shadecard/recipe-calculator) - [Read your result](https://abdohoo.app/help/shadecard/reading-your-result) - Blog: [What is trichromatic dyeing?](https://abdohoo.app/blog/what-is-trichromatic-dyeing) ## Frequently asked questions ### Do the three numbers have to add up to 100? Library ratios are written as parts that usually total 100, but the calculator accepts any numbers and normalises them automatically. ### Which yellow, red and blue dyes should I use? Three compatible dyes of the class that suits your fibre, ideally a trichromatic set your supplier sells for that class. The app shows an example set per fibre; check the supplier's recommendation. ### What does % owf mean? On weight of fabric: grams of dye per 100 g of dry fabric. 2% owf on 500 g of cloth is 10 g of dye in total. ### Does choosing a different fibre change the ratio? The library ratio stays the same; the fibre sets the dye class and the example dyes shown. Your own dip history is kept per dye class, so corrections learned on cotton are not applied to polyester.