Level 5: Perfume Mathematics and Formula Design
Weight-based formulation, active material, normalization, scaling, substitution and records that let a formula be repeated.
Lessons
The units of a formula
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Weight, Not Volume: Study Guide and Density Check
Read our weight and volume guide, then measure the density of two liquids and calculate how far a volume-based formula drifts from a weighed one.
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Percent and Parts: Study Guide and Drill
Read our parts-per-thousand guide, then practice moving a formula between grams, percent and parts until you can spot a wrong total on sight.
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Percent to Grams: Study Guide and Batch Drill
Use our percent-to-grams guide, then work a batch sheet from a library formula, checking whether each line can actually be weighed on your scale.
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Perfume Formula Practice Problems
Twelve worked practice problems on perfume formulas: totals, shares, dilutions, stocks and batch sheets, with answers to check against.
Active material and solvent
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Stock Solutions in Practice
How to plan a working set of stock solutions: choosing strengths, weighing from them, how much solvent they add, and keeping a shelf of them in order.
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Active Material: The Number Behind Every Formula
How to calculate the pure material in a formula with diluted lines, and why finishing a perfume to a stated strength goes wrong if you skip this step.
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Solvent in a Formula: What It Does to Your Numbers
Work through what happens when you change a line's dilution: three ways of doing it, what each holds constant, and when solvent changes the smell too.
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Absolute and Relative Percentage: Study Guide
Read our guide to absolute and relative percentage, then calculate all three shares for a formula and decide which one answers each practical question.
Scaling and normalizing
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Normalize a Formula to 1,000 Parts
Normalizing puts any formula on a common total so that versions can be compared line by line. Learn the method, how to round, and how to treat diluted lines.
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Scaling a Batch: Study Guide and Exercise
Read our scaling guide, then scale one formula up and down, finding the point at which smaller batches stop being weighable and larger ones cost too much.
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Perfume Dilution Practice Problems
A harder drill set on dilutions: mixing two strengths, stepping down in stages, recovering a batch and working backward from a finished perfume, with answers.
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Spot a Calculation Error: Study Guide
Use our batch errors guide, then audit a deliberately flawed batch sheet and find its five mistakes, building checks that catch errors before weighing.
Making a formula repeatable
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Formula Versioning: Study Guide
Read our version control guide, then bring order to your own Level 4 trials: number them, link each to its parent, and record exactly one reason per version.
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Material Substitutions: A Controlled Method
How to replace a material without losing the formula: define what it does, choose candidates, adjust for strength, test blind and record the change.
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Documenting a Formula: Study Guide
Use our formula template guide and its download, then test your documentation by handing a formula to someone else, or to yourself a month from now.
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Reproducibility Test: Weigh It Twice
Read our repeatable batches guide, then make one formula twice on separate days and test blind whether you can tell them apart. A plain test of your method.
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Working a Formula in the RUŌOD Lab App
Level 5's project: take a formula through the arithmetic by hand, then check it against a tool. Includes what the RUŌOD Lab app does and what it will not do.