Color Balance

[Lasergreg]

With the discussion on Color brightness, I decided to post my initial notes, working toward a eventual standard for Color balance and Modulation.

Comments are welcome...!

[Peter Broerse]

With the discussion on Color brightness, I decided to post my initial notes, working toward a eventual standard for Color balance and Modulation.

Comments are welcome...!

Hi Greg,

So if I am reading your document right and am doing the right calculation...??...I end up with the fact that:

For a good RGB mix using 532, 635 and 473 I need 2 x the amount of green as red and 3 x the amount of green as blue ?

IN figures this reads:

1000 mW green
4000 mW Red
8000 mW Blue

Together makes a 13 watt bright white ?

Or am I doing something wrong here ?

Cheers,

Peter

[Lasergreg]

Peter,

yes you have a decidedly unbalanced ratio of beam power to color, so your number are in the right direction. This is also part of the reason that I personally prefer 473 blue to 457.

However, equal brightness does not necessarily make white. The ratios are much more forgiving (roughly 2:1, not 8:1), but it is very dependent on the specific wavelengths.

Play with the Chromaticity Applet and you should get a good idea.

Greg

[Pangolin]

One more detail. Sometimes people mistakenly try to apply the CIE Chromaticity Diagram to lasers. This will not show the complete story, because it doesn't take into account effects that are unique to laser light, such as Raleigh Scattering and Forward Scattering, both of which provide higher visual efficacy with shorter wavelengths. This is why you need less blue laser light than the CIE Chromaticity Diagram would suggest...

Bill

[Lasergreg]

Bill,

Do you have any sources for calculating specific values of scattering versus wavelength? I found one source, and for the fog particle size we typically have, the difference between the different blue wavelengths (ie: 473, 457, 445) was actually pretty small. Much larger difference between blue and red, of course.

Greg