Color Formula
Salon workflow guide

Building a Reliable Client Formula Card System (And Why Paper Cards Fail)

To keep track of client hair color formulas reliably, record one searchable card per client that captures brand and line, shade numbers, color-to-developer ratio, developer volume, grams or parts, the client's starting and target level, processing time, and a confidence note for next time. Loose paper cards and camera-roll photos fail because they get lost, cannot be searched, and rarely record the starting level the result depended on.

What a card needsAbout Color Formula
The complete card

What a formula card actually needs to be reproducible.

A formula is only reusable if the next person reading it (which is often you, six weeks later) can rebuild the same bowl over the same head. That takes more than two shade numbers scribbled on a tab. A complete card records the recipe, the conditions it was mixed for, and a note about what to change. Here is the full field list, in the terms colorists already use.

  1. Brand and line

    Not just "6N." Record the manufacturer and the specific line, because a 6N in one permanent line is not the 6N in another. Shade numbering, pigment load and base differ between brands, so the brand and line are part of the recipe, not a label.

  2. Shade numbers and how they combined

    The exact shades and any mixing, including the toner or corrective drops. If you blended two shades, record both and their proportions. "6N plus a touch of gold" is a memory, not a formula; "30g 6N + 10g 6.3" is one you can rebuild.

  3. Color-to-developer ratio and developer volume

    The ratio (1:1, 1:1.5, 1:2) and the developer volume (10, 20, 30 or 40) drive how the mix lifts and deposits. The same shade at a different ratio or strength is a different service. Record both, every time, because the chemistry depends on them.

  4. Grams or parts, written down

    "Equal parts" is fine until someone needs the actual yield. Recording grams (or consistent parts) means the next bowl is the same size and the same strength, and it is the only way to attach a per-bowl cost later.

  5. Starting level and target level

    This is the field paper cards almost always miss. The universal level scale runs 1 (black) to 10 (lightest blonde). The same formula over a level 5 base and a level 7 base lands in two different places. Recording the starting level and the target turns a recipe into something judged against the right starting condition.

  6. Processing time and a confidence note

    Time at the bowl is a variable, not a footnote: outcome depends on reaction time as much as on the products. Close with one honest line about what to adjust: "ends grabbed warm, pull toner through last 5 minutes" is worth more next visit than the formula alone.

Outcome in permanent color depends on the products, their quantities, the starting hair, pH, reaction time and temperature, which is why a card has to record conditions and not just shades. See Comprehensive Review of Hair Dyes (NCBI / PMC) on the variables that govern the result.

The failure modes

Why paper cards and camera-roll photos fail in practice.

Most colorists do not lose formulas because they are careless. They lose them because the storage method was never built to survive a busy chair, a covered shift, or a year of repeat visits. The two most common systems both break in predictable ways.

The paper card

  • Gets lost, misfiled, water-stained at the bowl, or faded until the pencil is unreadable
  • Cannot be searched: finding one client in a box of cards is a manual hunt
  • Runs out of room, so the starting level and the next-time note get dropped first
  • Has no privacy boundary: client names sit in an open drawer anyone can read
  • Does not travel: it lives in one salon, so a covering colorist cannot reach it

The phone photo

  • Buried in a camera roll with thousands of unrelated images and no client name attached
  • Shows the tubes or the bowl, but rarely the ratio in grams, the volume, or the processing time
  • Almost never records the starting level, the one thing that makes the result repeatable
  • Sits in a personal photo library that may sync to shared cloud accounts and family devices
  • Degrades into guesswork the moment you need to read a number off a blurry label

A photo proves you did the service; it rarely lets you reproduce it. The gap is the missing context: the starting condition, the exact ratio, and the note about what to change. That is the difference between a record and a reproducible formula.

Why the starting condition matters

A starting-level record is as important as the recipe.

Oxidative hair color is a chemical reaction, and a reaction is defined by what it starts from. The recipe is half the information; the hair it was applied to is the other half. A card that records only the shades is recording only half of what made the result happen.

  1. The same formula gives different results

    Apply an identical mix over a level 5 and a level 7 base and you get two different outcomes, because there is less to lift and a different underlying warmth to neutralize. Without the starting level on the card, a repeated formula is a guess wearing the clothes of a record.

  2. Repeat clients are not static

    A client's base shifts: gray comes in, regrowth changes the canvas, a previous color builds up on the ends. Recording the starting level each visit lets you see the trend across visits instead of assuming last time's base still applies.

  3. It is what a covering colorist needs first

    Someone picking up your chair cannot read your hands. The starting level, target and ratio are the context that lets them apply your formula intelligently rather than copying numbers blindly. Industry bodies that set consultation standards, such as the Professional Beauty Association, treat the documented client record as core practice for exactly this reason.

  4. It makes the confidence note meaningful

    "Lighten 5 minutes next time" only means something against a known starting level. Tie the adjustment to the condition it was made under, and the note becomes a real instruction instead of a vague reminder.

The privacy boundary

Client formula data should stay on the device.

A client list with names, visit history and notes is sensitive data. The most reliable formula system is also the one that does not scatter that data across photo libraries, spreadsheets and accounts. Reliability and privacy point the same direction: collect only what you need to reproduce the service, and keep it somewhere you control.

What a private system looks like

  • One device, under your control, holding the records
  • No account to create and no shared directory of your clients
  • Only the fields needed to reproduce the service, nothing extra
  • Searchable by client name without exposing the list to anyone else
  • Notes and starting levels that never land in a synced camera roll

What to avoid

  • Client photos in a personal library that syncs to family devices
  • Formula spreadsheets emailed around or stored in open cloud folders
  • Collecting more personal detail than the service actually requires
  • Any system where losing one login exposes the whole client list
  • Paper cards left where walk-by traffic can read client names

Apple's developer guidance is to minimize the data an app collects and, where possible, keep personal data on the device rather than sending it off. See Apple, User Privacy and Data Use. A formula system built that way keeps the client list yours.

From a good card to a good system

The card is the easy part. The system is the point.

Anyone can write a good formula card once. The hard part is a system that captures every field the same way, every visit, stays searchable by client, survives a covered shift, and keeps the data private. That is the gap between knowing what a card needs and actually having one you can rely on.

Color Formula is that card system. It captures the formula, ratio, volume, grams, starting and target level, notes and a confidence label per client, and keeps everything on-device with no account. If you have read this far, you already know the fields; the app is the place to put them. Coming soon to the App Store.

About Color Formula Privacy Policy Support
Related reading

Go deeper on the numbers a card records.

  1. 10 vs 20 vs 30 vs 40 volume

    What each developer volume actually lifts, so the volume field on your card means something concrete.

  2. Mixing ratios explained

    Why 1:1, 1:1.5 and 1:2 change the result, and why the ratio belongs on every card.

  3. The real cost of a color bowl

    The per-gram method that turns the grams on your card into an actual material cost.

  4. Converting a formula between brands

    Why brand and line belong on the card, and why a cross-brand swap is a starting point, not an exact match.

Answer-first FAQ

Straight answers.

What is the best way to keep track of client hair color formulas?

Record a complete, searchable card per client: brand and line, shade numbers, color-to-developer ratio, developer volume, grams or parts, the client's starting level and target level, processing time, and a note on what to adjust next time. Store it somewhere searchable by client name and private to you, rather than on loose paper cards or in your camera roll, which get lost, cannot be searched, and rarely record the starting level the formula depended on.

What information does a complete formula card need?

Brand and line, the exact shade numbers, the color-to-developer ratio, the developer volume, the grams or parts of each component, the starting level and target level, the processing time, and a short confidence note. The starting level matters as much as the recipe, because the same mix on a different base gives a different result.

Why do paper cards and phone photos fail?

Paper cards get lost, misfiled, water-damaged or faded; a photo of the bowl lives in a camera roll with no way to search it by client and usually records the products but not the starting level, the ratio in grams, or the processing time. Neither has a privacy boundary, so client records sit in shared photo libraries or open drawers.

Why does the starting level matter so much?

Oxidative color is a chemical reaction, and the result depends on the hair it starts from. The same formula over a level 5 base and a level 7 base lands in two different places. Recording the starting and target level lets the next colorist judge the formula against the same starting condition.

How do I keep client formula data private?

Keep the records on a single device you control, avoid accounts and shared directories, and collect only what you need to reproduce the service. Apple's guidance for apps is to minimize collected data and keep personal data on the device where possible, which keeps client names and notes out of shared photo libraries and cloud accounts.