Why the Same Color Looks Different on Cotton and Polyester
The same Pantone code can look different on cotton and polyester because the two fibers take dye in different ways. Cotton is normally dyed with reactive dyes and polyester with disperse dyes, so a color approved on one fabric does not carry over to the other.
Cotton and polyester need different dye classes, and their surfaces reflect light differently. A dye house builds a separate recipe for each fabric, so the same code can land a little differently on each. Ask for a lab dip on every fabric in the garment and agree a separate tolerance for fabric-to-fabric matching.
Why the same code does not look identical
- Different dye chemistry. Cotton is a hydrophilic cellulose fiber. Polyester is hydrophobic. In polyester and cotton blends, the conventional method dyes each component separately under its own best conditions, using disperse dyes for polyester and reactive dyes for cotton (NMIMS paper (opens in a new tab)).
- Different surface and structure. Fiber, yarn and knit or weave structure change how light reflects. A smooth filament polyester and a matte cotton jersey can show the same color differently even when the measured dye depth is close.
- Different starting point. The base color of the fabric before dyeing affects the result. See Lab Dip Explained for why the swatch has to be dyed on the real fabric.
- Different limits. Each fiber and dye combination can reach some shades more easily than others, especially very bright colors.
What happens in cotton and polyester blends
In a blend, each fiber has to be dyed with its own dye class, and the two results must look like one color. The conventional exhaust method dyes each component separately under its own best conditions, which is why blends take more control than a single fiber.
A 2024 study in Scientific Reports (opens in a new tab) compared ways of dyeing cotton with reactive dyes and polyester with disperse dyes. It found that two-phase processes matched the two components closely, with ΔE CMC(2:1) well below 1, while a one-bath, one-phase process gave values above 1 in some shades.
What TCX means on polyester
TCX colors are defined on cotton. A polyester lab dip is the dye house's attempt to reach the same color on a different fiber. Expect it to be close and not identical, and approve it on your actual fabric. Keep the Pantone cotton swatch as the visual standard.
How to specify a garment that uses several fabrics
- List every fabric and fiber in the garment: shell, rib, lining and mesh.
- Give one TCX code for the color, and ask for a lab dip on each fabric.
- Mark rib, tape and drawstrings as dye to match, and approve each one.
- Agree a tolerance for fabric-to-fabric matching. It is usually wider than the limit for one fabric, because matching across fibers is harder.
- Check every combination under two light sources, such as D65 and TL84.
- Use the same fiber for matched parts where the design allows it.
Keep the approval on paper
Record each fabric's approval in writing with the code, the fabric and the light sources used. Then read Shade Variation Explained for what tolerance to expect between dye lots once bulk production starts.
Frequently asked questions
Can cotton and polyester ever match exactly?
Not with a guarantee. Different fibers use different dyes, so a dye house aims for a match within an agreed tolerance and checks it under more than one light source. Expect a small difference and agree the limit in writing.
Does the same Pantone code mean the same dye recipe?
No. A code defines the target color. The recipe depends on the fiber, the fabric and the dye class, so each fabric needs its own lab dip.
Should I approve cotton and polyester colors together?
Approve them separately, then check them side by side in the same light. Each fabric needs its own written approval before bulk dyeing. Use the Delta E calculator to compare the measured values.
Sources and further reading
Need a lab dip or bulk dyeing from Bangladesh?
Send your TCX code, fabric and target tolerance with your tech pack. We will advise on achievable color tolerances for your production run.
Request a Lab Dip QuotePANTONE® and TCX are trademarks of Pantone LLC. SDF Clothing is not affiliated with or endorsed by Pantone. The color values on this site are approximations for reference and are not Pantone data.