How we test hair foil
Every finished box of hair foil is checked in four steps: the box and its print, the sheet count by weight, the folds and the emboss. Beyond that inspection, 7 tests answer the questions buyers ask about the foil itself, from thickness to grip. Each test has a written method, set out below with the question it answers.
How each finished box is checked
Inspection is done on the finished product, box by box, in this order.
- Box and print. The closed box is checked for damage and for faults in its print.
- Count by weight. The box is opened and the sheets are weighed. The weight shows whether the box holds the number of sheets stated on it, without counting by hand.
- Folds. The folds are checked for defects.
- Emboss. The emboss pattern is checked to be fully pressed.
The checks that come before boxing, on the foil coil and on the line, are on the quality lab and inspection gates page.
The tests at a glance
Each test exists because of a complaint a salon makes about foil. The table lists the question each one answers.
| Test | What it checks | How |
|---|---|---|
| Thickness measurement | Is the stated thickness the real thickness? | Measure the bare foil before embossing at 5 set points on each of 10 sheets per SKU (50 readings); record the mean and the range. |
| Fold-with-bleach integrity | Does the foil tear when folded with bleach on it? | Apply the same bleach formula at the same coverage and contact time, fold the foil three times and inspect each fold. |
| Comb-tail pierce | Does a tail comb pierce the foil? | Draw a tail comb across the foil with the same comb tip, support, force and stroke length for every sheet; record the number pierced. |
| Pop-up dispense | Do sheets stick together or come out more than one at a time? | Pull every sheet from each box in turn; record double pulls, stuck sheets, empty pulls and tears separately. |
| Transit condition | Do boxes arrive usable, with the sheets flat? | Put packed export cartons through a drop and stacking sequence chosen for the carton weight and the shipping mode, then open them and check each box and its dispensing. |
| Grip / slip | Does embossing reduce slipping? | Place a wet hair swatch and the foil on an incline; measure how far the foil slides. Embossed and smooth foil of the same thickness are compared. |
| Printed ink vs bleach and developer | Does printed ink come off or transfer to hair? | Expose printed foil to bleach paste under the conditions the product allows, wipe it, and check the print and a white hair swatch. |
Each test is described below: the question it answers and how it is run. The same checks can be repeated on your samples; the last section says how.
Thickness measurement
Stated thickness is the first thing a buyer cannot check by eye. It is measured with a micrometer at set points across the foil, and recorded as a mean and a range.
Thickness measurement
- What it checks
- Is the stated thickness the real thickness?
- How
- Measure the bare foil before embossing at 5 set points on each of 10 sheets per SKU (50 readings); record the mean and the range.
How thickness relates to alloy, temper and handling is on hair foil thickness and alloy.
Fold-with-bleach integrity
Foil is not folded dry. It is folded with lightener on it, and a wet, loaded fold is where thin or brittle foil breaks.
Fold-with-bleach integrity
- What it checks
- Does the foil tear when folded with bleach on it?
- How
- Apply the same bleach formula at the same coverage and contact time, fold the foil three times and inspect each fold.
Comb-tail pierce
A colourist weaves with the tail of a comb pressed against the foil. A foil that the tail goes through lets product onto the hair beneath.
Comb-tail pierce
- What it checks
- Does a tail comb pierce the foil?
- How
- Draw a tail comb across the foil with the same comb tip, support, force and stroke length for every sheet; record the number pierced.
Pop-up dispense
A pop-up box has one job: to hand over one sheet at a time, down to the last sheet.
Pop-up dispense
- What it checks
- Do sheets stick together or come out more than one at a time?
- How
- Pull every sheet from each box in turn; record double pulls, stuck sheets, empty pulls and tears separately.
The manufacturing causes behind a box that fails this test are explained in why pop-up foils stick, tear or arrive bent.
Transit condition
Sheets that leave the factory flat can arrive bent. This test is run on boxes packed in export cartons, after a simulated journey.
Transit condition
- What it checks
- Do boxes arrive usable, with the sheets flat?
- How
- Put packed export cartons through a drop and stacking sequence chosen for the carton weight and the shipping mode, then open them and check each box and its dispensing.
Grip
Embossing is sold on grip. This test measures it against smooth foil.
Grip / slip
- What it checks
- Does embossing reduce slipping?
- How
- Place a wet hair swatch and the foil on an incline; measure how far the foil slides. Embossed and smooth foil of the same thickness are compared.
The result for each pattern is on hair foil emboss patterns compared.
Printed ink vs bleach and developer
Printed foil is in contact with lightener for the whole processing time. This test checks whether the ink stays where it was printed.
Printed ink vs bleach and developer
- What it checks
- Does printed ink come off or transfer to hair?
- How
- Expose printed foil to bleach paste under the conditions the product allows, wipe it, and check the print and a white hair swatch.
The photographs and the limits of this test have their own page: printed hair foil ink vs bleach.
Tests you can run on samples
None of these needs laboratory equipment. They are the checks we suggest when samples arrive.
| Check | How | What to look for |
|---|---|---|
| Thickness | Micrometer, or weigh a piece of known area | The stated gauge, and little variation between pieces |
| Wet fold | Apply lightener, fold three times | No breaks along the folds |
| Comb | Draw a tail comb across the foil with working pressure | No piercing |
| Dispensing | Pull a full pop-up box, sheet by sheet | One sheet per pull, to the bottom of the box |
| Flatness | Open the box as delivered | No bent or creased sheets |
| Soak printed foil in your own lightener for your longest processing time | No ink on a white swatch |
The equipment and inspection gates behind these tests are described on the quality lab page.
FAQ
How do you test hair foil for tearing?
Hair Foil Factory tests hair foil for tearing in the condition it is used in: wet. A standard bleach paste is applied to the foil, the foil is folded three times, and the folds are inspected for breaks. Smooth and embossed foil are tested side by side.
Why does a comb tail go through some foils?
A comb tail goes through hair foil when the foil is too thin for the pressure applied, or when its thickness varies and the comb finds a thin place. Hair Foil Factory draws a tail comb across the foil with the same comb, support and force each time and records how often it pierces.
How do you test pop-up dispensing?
Hair Foil Factory tests pop-up dispensing by pulling every sheet from a full box, one after another, and recording how many pulls deliver exactly one sheet and how many sheets stick.
Can I see test results for my order?
Every order is inspected box by box before it is packed. Ask for the inspection details of your order with your quote, or book a third-party inspection before shipment through your own inspection company.
What tests should I run on samples?
On hair foil samples, check five things: measure or weigh the foil to confirm thickness; fold it wet to see whether it tears; draw a tail comb across it; pull a full box of pop-up sheets one by one; and inspect the box for bent sheets on arrival. For printed foil, add a bleach soak.