1. Umbrella fabric
Umbrella surface is the key to measure the effect of UV protection. And summarize the following points: (1) cotton, silk, nylon fabrics are not as good as polyester; (2) some umbrella fabrics are thin and sparse, so it's better to choose the one with tight fabric; (3) satin fabric is the best, then twill and plain; (4) the darker the fabric, the better. When you pick an umbrella, you may as well open it to see the shadow on the ground. The shadow is dark.
2. Light transmittance
Transmittance refers to the percentage of luminous flux passing through a transparent or translucent body and its incident luminous flux. We found that when we judge whether an umbrella is sunscreen, we often mix two concepts: UV protection and transmittance. These two are totally different. We must bear in mind.
The wavelength of ultraviolet light in the sun is different from that of ordinary light, and ultraviolet light can't be seen. If you take a black umbrella, you will feel black under the umbrella, which gives people the feeling of sunscreen. But if you take an umbrella and sit there fishing for a day, you will find that you will still be sunburned, and your skin will be red or even molting. The conclusion is that the light transmittance mainly considers the adaptability of the eyes. The UV protection index is invisible, which is an important index for health protection. So pay attention to the difference between the two.
3. Umbrella ribs, styles, etc
After reading the most important indicators, the rest depends on your personal preferences. Like four fold or three fold umbrella, various styles, colors, or portable, etc. according to the different needs of each person to measure.
Reminder of professional umbrella makers:
Rain has a corrosive effect on the sunscreen coating. In order to maintain the sunscreen performance of the sunshade, it must be used separately from the umbrella. If the umbrella surface is dirty, you can use a soft brush dipped in water to gently brush, but not with your hands, and do not wash too often, otherwise it will also affect the sunscreen effect.