Infrared vs. non-infrared

The question we get most often: what's the difference between a regular CROC iron and an infrared one?

The short answer

A regular titanium iron heats the hair from the outside in. The plates are hot, the hair touches them, heat moves inward.

Infrared works the other way round. The heat penetrates the cortex — the inside of the strand — so the hair reaches styling temperature from within rather than only at the surface. Thermal conduction brings the inside and the outside to a uniform temperature, which means less friction as the plates travel and less of the surface damage that comes with repeated passes.

The practical difference shows up over time rather than in a single use: hair that has been styled on infrared tends to feel softer and look healthier than hair styled at the same temperature without it.

We put it in front of a lab

Rather than assert it, CROC commissioned a microscopy study. Here is exactly what was done.

Procedure. A human hair sample was divided. One portion was mounted on a sample carrier and analysed untreated. The other was ironed with a CROC Professional Infrared iron heated to 380°F with the infrared function activated, and passed four times.

Analysis. Both portions were examined on a JEOL JSM-6010PLUS/LA scanning electron microscope at an accelerating voltage of 15 kV, with elemental analysis by energy-dispersive X-ray spectroscopy (EDX) using a JEOL EX94400T4L11 Dry SD detector. Elemental results were quantified by weight (mass%) and atomic percent (Atom%).

What the images showed. On the untreated sample, the cuticle — the outer layer of overlapping scales — was irregular, with slight lifting, and shiny material embedded between some layers. On the infrared-ironed sample, the cuticle surface was better sealed and better aligned, producing a visibly smoother surface.

A sealed, aligned cuticle is what reflects light evenly. That is what shine is, physically.

Which CROC tools are infrared

Nine of our eighteen tools are infrared — it runs across the range rather than sitting in one line:

Infrared models say so in the product name. If "Infrared" isn't in the title, that model heats conventionally — which is the right tool for plenty of hair types, and cheaper.

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Getting the most from it

• Infrared does not mean you need more heat. Start lower than you would on a non-infrared iron.
• Fewer passes beat more passes at any temperature. The study above used four.
• Keep the plates clean — product residue sits between the plate and the hair and defeats the point. On infrared models, clean the infrared strip with a cotton swab so it doesn't clog.