The word openness is thrown around quite a bit in regards to roller shades. It’s a word that designers and shade manufacturers have coopted to basically mean how much light comes through a shade fabric. Yet there is incredibly limited information amongst manufacturers about how openness is tested and decided. Which means that openness can actually differ one manufacturer to the next.

The facts are that there is no standardized testing for openness. If a certain manufacturer does have a testing mechanism for their own fabrics then it would be fair to trust their assessment amongst fabrics that they produce, but a comparison to a competitor’s fabric cannot be relied upon. At the simplest level, openness is the amount of light that is allowed to come through the fabric. It is also to a certain extent, the clarity of the image or view which can be seen through the shade fabric.

The only trusted number is an openness factor of 0%. It can also be called opaque and that means that a fabric lets no light through and an image cannot be seen through the fabric. A fabric that is opaque will be considered a blackout shade fabric.

A Few Tips We Recommend:

Blackout fabrics should always be 0% open or opaque.
Sheer fabrics should always be considered to allow the most light through. In the nebulous industry talk, we would recommend thinking of sheer as anything manufacturers are calling 3% open or greater.
Basketweave fabrics are the fabrics that most often get a specific openness label attached to them and that’s because the fabric is woven in a traditional basketweave pattern at a large enough scale for the pattern to be visible to the naked eye. That in mind, the tightness or looseness of that weave will alter the amount of light that comes through.

The reason we at Quiltcraft are wary of the openness factor and would advise you to be as well, is because without an industrial standard definition and testing mechanism, openness is incredibly subjective. What we might consider 5% open, the next person could consider 7%. We would suggest seeing the fabrics for yourself and testing them based upon your own eye. A fabric considered to be 5% open will look to be a lower openness on a dark overcast day, but then may seem to be a greater openness when hit with direct sun.

**For Other Helpful Info…**

Check out our post on When Should You Use What Type of Roller Shade Fabric?

We hope that this explanation has been helpful to you in your consideration of roller shade fabrics for future projects. At Quiltcraft, as with most good manufacturers, samples are readily accessible and can always be sent out for your personal viewing and decision-making process.