Translations:Dark period/13/en
From Polyphasic Sleep Wiki
The most popular and versatile method for achieving a dark period is through the use of red-coloured laser goggles (colloquially known as "DP goggles" in the Discord community). There are several types of these available, and below is a comparison between their light-filtering lens tints.
The data and the links here are sourced from online stores on Taobao and other websites, but not all have been confirmed by the editors here. The data has also not been independently verified by ourselves, and the Wiki makes no guarantee of validity of this data.
| Filter type | Specification | Transparency | Verdict | Sample Image |
|---|---|---|---|---|
| Dark red | 200-540 nm @ 99.99% min | data not found | Recommended | 
|
| Light red | 200-540 nm @ 90% min | data not found | Recommended | 
|
| Orange 2 | 
|
35% | Recommended | 
|
| Orange 1 | 
|
30% | Recommended | 
|
| Yellow | 
|
50% | Useful but not ideal | 
|
| Light yellow | data not found | 85% | Avoid | 
|
Notes:
- The dark red goggles may be too dark and reduce vision, but this would be useful during daylight hours or in bright environments.
- The light red goggles let in substantially more red and green light than the orange one, but less yellow. The overall brightness appears to be slightly higher for the orange one, but the orange one allows for more colour perception. Based on the melanopic sensitivity function, both should provide similar levels of protection against melatonin suppression.
- There is a significant price difference between the first two and the third and the fourth one. However, the third and fourth ones have better quality (fewer rough edges on the plastic, more uniform transparency, and provide more options).
