Why doesn’t expensive museum glass reflect light?

Many people who go to museums feel the same way. The glass in good exhibition halls is as if it doesn’t exist, and there is almost no reflection when taking photos. In fact, this is not an illusion. Expensive glass can indeed achieve low reflection. Ordinary glass itself can transmit light and reflect light. About 8% of the light will be reflected back, so it is easy to have light spots and reflections when taking pictures.

High-end museums use anti-reflective glass, also calledLow-reflective glass uses special processing to reduce the reflectivity to a very low level, and some can even reduce it to about 1%.

This kind of glass mainly relies on two processes to achieve non-reflection.One is to roughen the glass surface, so that the reflected light is dispersed and not obvious to the naked eye.Another more commonly used method is to coat the surface, by controlling the thickness of the film layer, the two beams of reflected light cancel each other out, reducing reflection from the source. The coating can also make a transition between air and glass, further reducing reflectivity, and the effect is more stable than surface treatment.

Good glass not only does not reflect light, but also meets the special requirements of museums, such as blocking ultraviolet rays to protect cultural relics, not deforming for long-term use, and being strong enough to be safe, all of which increase costs significantly.

It can be seen from the public procurement information that the price of professional low-reflective glass display cabinets is very high, with a set costing hundreds of thousands of yuan, and the overall investment of large venues is millions of yuan. It is indeed a result of the cost.

In addition to the glass itself, the lighting design of the showcase is also critical. The difference in brightness between inside and outside and the angle of the light source will affect the reflective effect. Professional venues will adjust the light to be brighter inside and not directly shine on the glass outside, further reducing reflection interference.