A Practical Comparison of Transmittance, Haze, Strength, and Shrinkage Across Eight Standard Gauges
BOPET film comes in many thicknesses, and the differences between them are not just about weight. Transmittance, haze, tensile strength, elongation, and thermal shrinkage all shift as the gauge changes. Choosing the right thickness means matching those properties to your process — not simply picking the cheapest or the thickest option. This guide walks through eight common BOPET gauges and what each one is best suited for.
Thickness Range at a Glance
We carry BOPET film in eight standard gauges: 25μm, 38μm, 50μm, 75μm, 100μm, 125μm, 188μm, and 250μm. The table below summarizes the key optical and mechanical values for each.
| Thickness | Transmittance (550nm) | Haze | Tensile MD/TD (MPa) | Elongation MD/TD (%) | Shrinkage MD/TD (%) |
|---|---|---|---|---|---|
| 25μm | 87.0% | 0.6% | 225 / 245 | 170 / 160 | 1.3 / 0.0 |
| 38μm | 86.9% | 0.6% | 225 / 245 | 140 / 130 | 1.3 / 0.4 |
| 50μm | 86.5% | 0.9% | 215 / 225 | 150 / 130 | 1.2 / 0.3 |
| 75μm | 86.5% | 0.9% | 215 / 225 | 150 / 130 | 1.2 / 0.3 |
| 100μm | 89.0% | 1.3% | 210 / 220 | 150 / 130 | 1.0 / 0.2 |
| 125μm | 85.6% | 1.6% | 205 / 215 | 150 / 140 | 0.9 / 0.3 |
| 188μm | 85.1% | 2.0% | 186 / 196 | 190 / 140 | 0.9 / 0.5 |
| 250μm | 84.0% | 3.0% | 176 / 186 | 190 / 150 | 0.9 / 0.6 |
Thin Gauges (25μm – 50μm): Clarity First
The thinner end of the range is where optical quality peaks. 25μm delivers the highest light transmittance at 87.0% with just 0.6% haze, making it the go-to choice for graphic arts, OHP sheets, and precision imaging. 38μm keeps almost the same clarity (86.9% / 0.6%) while adding a little more body for printing and label work. 50μm is the practical all-rounder — 86.5% transmittance, 0.9% haze, and enough thickness to run cleanly through lamination lines.
Mid Gauges (75μm – 125μm): Balance and Stability
From 75μm upward, the film gains body. 75μm handles large-format printing and repeated lamination without wrinkling. 100μm is unusual: it is the clearest grade in the entire range at 89.0% transmittance, despite being thicker than 50μm — a good pick when you need both clarity and handling strength. 125μm shifts the priority to stability, with MD shrinkage dropping to 0.9%, which helps when registration matters.
Thick Gauges (188μm – 250μm): Toughness and Structure
The two heaviest gauges trade optical clarity for mechanical strength. 188μm keeps 190% MD elongation, so it stretches under stress instead of tearing — useful for die-cutting and punching. 250μm is the thickest standard gauge; it holds its shape under load and resists cracking, which makes it suitable for structural base layers and heavy-duty converting. Transmittance drops to 85.1% and 84.0% respectively, with haze rising to 2.0% and 3.0%, which is normal at this thickness.
How to Choose
A simple rule of thumb: if clarity is the priority, stay between 25μm and 100μm. If dimensional stability matters more, look at 125μm. If the film has to survive mechanical stress or act as a structural layer, choose 188μm or 250μm. For general printing, labeling, and lamination work, 50μm and 75μm cover most jobs.
Not sure which thickness fits your process?
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