40 MICRON
How thick is the film?
The micron figure describes film thickness. It gives you a measurement to compare when reading product specifications.
FILM THICKNESS EXPLAINED
What does 40 micron mean for cello bags?
40 micron describes the thickness of the film: 40 micrometres, or 0.04 millimetres. It does not describe the size of the bag, how much it can hold, or a tested protection rating.
THREE DIFFERENT QUESTIONS
Thickness is not the same as fit
USABLE DIMENSIONS
Will my item fit?
Use the internal width and length in millimetres. Add the envelope, mount or backing board before measuring the finished set.
Use the Size GuideSUITABILITY
Is it right for my purpose?
Material, construction, closure and the way you pack the item all matter. A thickness number alone does not establish a bag’s strength or specialist suitability.
READING THE NUMBERS
Microns converted to millimetres
These are unit conversions, not ratings or a comparison of products we sell.
| Microns (µm) | Millimetres (mm) |
|---|---|
| 20 | 0.02 |
| 30 | 0.03 |
| 40 | 0.04 |
| 50 | 0.05 |
A thicker figure is not a guarantee
You cannot translate a percentage increase in thickness directly into the same increase in strength. Nor does “40 micron” establish waterproofing, UV protection, food-contact suitability or archival certification.
WHAT TO CHOOSE
Match the bag to your work, not just a number
Clear OPP presentation
Our 40 micron OPP bags are intended for clear presentation of prints, cards, photos and artwork, with a self-seal flap for closing. The same film specification is used for the 100 Pack and 200 Pack options.
FIT
The right size still comes first
A thicker film does not create extra internal room. Leave clearance for the item to slide in without forcing it, and use appropriate rigid packaging when sending work through the post.
Follow the buying guideUnit reference: BIPM SI prefixes. Product measurements on this page refer to the CelloBag range.
KEEP EXPLORING
More help choosing your bags
What are cello bags?
Start with the material, closure and typical uses.
Read guideCello vs cellophane
Know the difference between a product name and its material.
Read guideHow to choose cello bags
Work through size, clearance and pack quantity.
Read guideChoose your size with confidence
All eight CelloBag sizes use 40 micron OPP. Compare the internal measurements to find your starting point.