i have this fabric cotton I don't know if it protects against UV rays from the sun because it has pores and I don't know if it's good to use as a curtain so that dry air enters the room and dehumidifies it. in brazil name is flanela castronaves.vteximg.com.br/arquivos/ids/172201-1000-1000/…

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A textile engineer can answer your question. The cloth (shown in the picture) appears to be very dense and colored. It is likely to restrict passage of air and its color is likely to fade after some time. Any cloth can protect UV to some extent. Most cotton cloths can reduce incoming UV by reducing the overall amount of incoming radiation. Certain types of plastic cloths can reduce incoming UV by reflecting the incoming UV radiation. You may try curtains with multiple layers, and change them as per your needs. You may check Amazon web site and search for cloths with your criteria.

I don't care if the fabric changes color due to UV, I need it to offer good blocking to minimize UV ​​entry, but to be good for use as a curtain, is it better to use this cotton fabric (red or orange colors) or use 100% polyester fabric that is slightly transparent in white?

realthread.com/blog/uv-protection-cotton-vs-polyester may help.

According to the review in the link, polyester is the winner in terms of UV protection, but my white 100% polyester fabric is transparent. Is this a problem for UV blocking?

It is not a problem, but since it is opaque, it will restict visible radiations along with UV.

If you want, you may Edit your question to add 'applied-physics' as a Tag.

my white 100% polyester fabric is transparent is problem block UV?

If it is polyester, it will have a good UV protection. If it is transparent, it will allow visible radiation. If it is not threaded/woven, it will not breathe air. ... No fabric is likely to fulfill all your requirements.

It really is 100% polyester, similar to white plastic but it is transparent, is the visible radiation UV? Does it also dry out plastic and rubber?

Sorry, I am not knowledgeable enough to answer all your queries.

I don't know the answer either

Human beings can see visible radiation, but cannot see ultraviolet (UV) radiations. Visible radiations have lower frequencies than UV radiations. en.wikipedia.org/wiki/Electromagnetic_spectrum#/media/…

Does visible radiation also have an influence on drying out plastic and rubber, just like UV? Does 100% white and transparent polyester fabric allow UV to pass through?

Any type of electromagnetic radiation (microwave/ infrared/ visible/ ultraviolet/ xray) radiation can dry, and can be absorbed by, any type of material. How much? It varies and depends on many factors.

How to minimize this? Minimize as much as possible I only have this white transparent fabric, 100% white polyester, and cotton fabric. I thought about using it as a curtain on the window to let in air because the curtain moves and is not fixed to the wall. It has good protection against rays that dry out plastic and rubber.

Light colored fabrics absorb less visible/UV radiations than dark colored fabrics. A reflecting surface can reduce absorption of radiation.

The transparent 100% polyester fabric I have is white and the cotton fabric is orange or red. Which one protects better? cotton image:

castronaves.vteximg.com.br/arquivos/ids/172201-1000-1000/…