What the number is
Openness factor is the proportion of the woven fabric that is actual hole. One percent openness means one percent of the surface area is gaps between the yarns and ninety nine percent is coated yarn.
It sounds like a rounding error. It is not. That one percent is the difference between looking through a screen and looking at a wall.
One percent: you keep the view
At one percent openness you can see out. The fabric reads as a tint rather than a barrier, so the balcony still feels like it is outdoors and you still have your view of whatever you paid for the view of.
The published figures for the one percent fabric we supply: 26 percent polyester and 74 percent PVC, 600 g per square metre, 0.88 mm thick, 300 cm wide. UV screening up to 99 percent. Breaking strength greater than 2850 N per 5 cm on the warp and greater than 2000 N per 5 cm on the weft. Colour fastness grade 8.
Certification on that fabric: Oeko-Tex Standard 100 class IV, Greenguard Gold, RoHS, lead free, and fire classified to NFPA 701 TM#1 and BS 5867 Part 2 Type B. Those are manufacturer figures from the published fabric certificate, not our measurements.
Zero percent: you get the block
At zero percent the weave is closed. No view out, and correspondingly no view in, which is the reason people choose it. It is the privacy option and the full glare block.
Published figures for the zero percent fabric: 22 percent polyester and 78 percent PVC, 610 g per square metre, 0.82 mm thick, 300 cm finished width, yarn count 60 by 42. Breaking strength 3840 N per 5 cm warp and 990 N per 5 cm weft. Oeko-Tex Standard 100, Greenguard Gold, REACH, anti static, lead free.
How to actually choose
Ask what the blind is for. If it is glare and heat on a balcony you like looking out of, one percent. If it is privacy from a facing block, or a bedroom, or a projector wall, zero percent.
Colour matters more than people expect. A darker fabric cuts glare harder and gives you a clearer view through it, because your eye is not fighting a bright surface in the foreground. A lighter fabric bounces more heat off but glows when the sun is on it. Most people who want the view choose a dark grey or bronze, and most people who want the room bright choose a pearl or linen.
You can specify different fabrics on different bays of the same job. A west-facing bay taking the afternoon sun and a shaded side bay do not have to match in openness, only in frame colour.
The colours these fabrics come in
One percent: ZS 0105 White Grey, ZS 0450 Pearl Grey, ZS 0448 Grey Linen, ZS 0406 Black Bronze, ZS 0405 Black Grey.
Zero percent: ZS ZP3, ZP7, ZP8, ZP9, ZP10 and ZP19, in white grey, black grey, black, black bronze, grey and pearl grey.
Frame colours are separate from fabric: RAL 7012 as standard, plus white, light grey, starry grey and starry black. The frame is what your neighbours and your MCST see, so it is usually the one that needs approving.