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Today when I went for eye checkup, the optician presented to me an anti blue ray glasses. This type of glasses reflect blue light, and hence, while wearing my original glasses and holding this new pair of glasses under the light, it reflected blue light, as expected.

However, when I put on these anti blue ray glasses, and put my normal glasses under the light, I saw red light reflected. This confused me because under normal conditions, it would at most reflect the colour of the light. I suspected this might be because I was wearing the anti blue ray glasses, but I cannot arrive at a definitive conclusion yet. Anyone knows why this effect happens?

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  • $\begingroup$ White light from your glasses are incident on your anti blue ray glasses, so which colour is reflected (blue end of spectrum )and which colour is transmitted (red end of spectrum)? $\endgroup$
    – Farcher
    Aug 4, 2018 at 12:37
  • $\begingroup$ @Farcher I understand that blue light is not transmitted to my eyes when wearing the anti blue ray glasses, but what about the other colour lights like green or yellow? Why do I happen to see the red light only? $\endgroup$
    – QuIcKmAtHs
    Aug 4, 2018 at 13:46
  • $\begingroup$ @QuIcKmAtHs When you say the other colors like green and yellow are you talking about partial reflection off the lens? Read up on partial reflection or thin film optics. $\endgroup$ Aug 4, 2018 at 14:32

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When I put on these anti blue ray glasses, and put my normal glasses under the light, I saw red light reflected. This confused me because under normal conditions, it would at most reflect the colour of the light.

The light available to be seen depends on the office lighting and sunlight filtered through the glass. Different lighting light temperatures are available and each adds a different look to the room. This is something you are not usually going to notice or think about, but something that is enhanced when using filters.

Corrected Color Temperature (CCT)

Notice how a lower Kelvin light produces a warm and relaxing environment while a high Kelvin light produces a cool sterile environment. Lower is redder, higher is bluer, the Sun has a stellar classification of G2V, indicating a main-sequence star with a temperature around 5,800 K.

When you wear blue blocking glasses this is what happens:

Blue Blockers

If the office lights are reddish and you are blocking blueish light then the blue won't pass through your glasses (balancing the red to make the light whiter) and only the non-blue colors remain; with lower Kelvin light red predominates.

Similarly when you look at blue blocking glasses (from the front, non-viewing side) without filtering you can see blue reflected, and through the glasses.

Blue Blockers

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