jktales

Tales of Experimental Photography

Light Plane Photography and Laser Safety

Lasers are not toys!

Lasers are not toys!

Lasers are no toys, they are potentially harmful to your eyes and skin. In worst case a laser can blind you, your models, your audience or any bystanders. You need to be aware of the risks involved and need to understand as much technical details as possible before doing any work with lasers. Lasers need to be installed and operated in a way that no one can get hurt in any situation.

Luckily when working with line lasers, the output power of the laser diode is projected to a long line and therefore distributed to a relatively large area. So even with a laser of potentially dangerous output power the energy that can actually enter an eye is usually not enough to do any harm. But you need to make sure that this is the case in any potential situation. With line lasers, the closer your eye gets to the laser module itself the higher the energy will be that can enter your eye. When coming too close the energy can become harmful. Special care must be taken when the line generating optics are removed from the laser module as the point beam is much more dangerous. Potentially, even a 5mW point beam can do serious harm to a human eye. With point lasers, the distance between laser and your eye is almost irrelevant, a laser that can harm your eye at 5cm will do the same at 50m!

If you are using lasers that exceed 5mW output power I’d recommend to buy a laser power meter to ensure that no one can ever be exposed to a beam with enough energy to do any harm. It is very difficult to assess how much power a laser really has if you cannot measure the power directly. But if using a power meter be sure you understand how it is measuring the power and how the raw numbers need to be interpreted.

Be especially aware of cheap green laser modules which are readily available on the Internet. The DPSS diodes used in most of these modules can emit invisible infrared light with an energy surpassing their nominal output power. You can blind yourself without any warning as your eye cannot detect IR light and will not automatically close! If buying a green DPSS laser (“if it’s less than a few thousand dollars and green it’s most probably DPSS”) it’s recommended to buy only higher quality products and ask the seller if the module has a built-in IR-filter.

Looking straight into any laser beams should be avoided at any time, even with low power line lasers! Always tell your models and visitors to avoid looking straight into the beam! If unsure about the risks of your installation, use appropriate laser safety goggles at all times.

My notes here are very limited and might not depict the real risks, after all I am not a laser safety professional. Before doing any work with lasers, please read more about laser safety. Especially Sam’s Laser FAQ has many practical do’s and don’ts:

Many countries have laws regulating import and/or use of laser products. Check with your government if and how that applies to your country.

Next >>: How-To: A Simple LPP Installation

 

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