LED spectrum/visual perception

[oreo54]

740nm will relax Photosystem I (it absorbs at a max of 700nm thus called P700.) This will could help prevent damage to Photosystemm II .

Out of curiosity ... so what do you think about this spectrum?
Pretty much out of the ordinary so I'm curious.

 

[Dana Riddle]

Out of curiosity ... so what do you think about this spectrum?
Pretty much out of the ordinary so I'm curious.

Looks OK to me. The violet spike is pretty much outside of the protective xanthophyll bandwidth (as opposed to the blue spike at about 450nm.) The aqua bandwidth can be absorbed by the accessory pigment peridinin and transferred with almost 100% efficiency to chlorophyll a and the reaction centers. And a little red for photosynthesis and visual appeal.

 

[oreo54]

Thanks...

 

[Dana Riddle]

Here's the visible spectrum of the Orphek Reef Daylight Plus luminaire. I need to extend the calculations into the infrared range.

 

[taricha]

On visual perception, does everything blue look the same to others eyes? Or just me?
A fixture with 420 and 450nm LEDs look exactly the same to my eyes. I can either check them with a meter, or if I put an orange filter on, a little bit more of the 450 squeezes through.
405 looks totally violet, 420 totally blue and identical to 450.

 

[Dana Riddle]

And with IR added:

On visual perception, does everything blue look the same to others eyes? Or just me?
A fixture with 420 and 450nm LEDs look exactly the same to my eyes. I can either check them with a meter, or if I put an orange filter on, a little bit more of the 450 squeezes through.
405 looks totally violet, 420 totally blue and identical to 450.

I can visually see definite differences between the 422nm, 451nm and 468nm LEDs.

 

[taricha]

I can visually see definite differences between the 422nm, 451nm and 468nm LEDs.

Oh no. I guess I'm blue-blue colorblind! [emoji1]

 

[Dana Riddle]

Oh no. I guess I'm blue-blue colorblind! [emoji1]

Maybe not - I suppose it depends upon the bandwidth (specifically the Full Width at Half Maximum - FWHM.) I have some LEDs advertised to have a peak at 450nm (which is true) but appear to be purple due to the presence of a red shoulder.
I'm really curious about your lab. It must be rewarding to work with Atlantic corals, something I wish I could do. But I understand permitting is as big a pain as it was in Hawaii.

 

[taricha]

I'm really curious about your lab.

Heh. I teach high school so the lab is a classroom lab, my supplies and equipment are whatever I can get my hands on, and my test organisms come from my tank. [emoji16]

 

[Dana Riddle]

Heh. I teach high school so the lab is a classroom lab, my supplies and equipment are whatever I can get my hands on, and my test organisms come from my tank. [emoji16]

I know the feeling. With what I've spent on lab equipment, I could have had a Mercedes sport coupe. Hmmm... Mercedes or lab stuff? - lab stuff! There's plenty of equipment I would love to have, but my retirement dollars won't stretch that far. When I was in Hawaii I had access to a great wet lab (in addition to mine) but didn't have the time. Now, time is a little more available, but no wet lab with its heat blocks, digesters, etc.

 

[Jase4224]

So after a bit of a re-think I’ve decided that using two blue bars and one white(er) bar simply won’t give me the results I’m looking for. I’ve decided that one blue bar for morning and evening with two white bars for midday actually works much better in every respect: better spectrum for photosynthesis, better looking spectrum and even cheaper on power.

First my blue/actinic bar x 1

Second is my white bars, this shows bar x 1

Third this is the overall result of 1 x blue and 2 x white

Of course these will be on timers with the blue turning on first and turning off last with the white bars timed separate so the tank gets brighter/darker gradually.

What do you guys think?

 

[oreo54]

I like mine better..

 

[Jase4224]

I like mine better..

Lol everybody has different tast

 

[Dana Riddle]

Lol everybody has different tast

Exactly - this is one reason I no longer spend a lot of time discussing the 'best' light (there isn't one). A light source could promote photosynthesis with 100% efficiency, make corals the colorful possible and many would not use it because they think the light is ugly.

 

[Jase4224]

Exactly - this is one reason I no longer spend a lot of time discussing the 'best' light (there isn't one). A light source could promote photosynthesis with 100% efficiency, make corals the colorful possible and many would not use it because they think the light is ugly.

Agree. The ‘best’ light just for growth might end up being purple lol

For me I don’t want a dark blue tank. I like lighter blue. But I also don’t want lots of peaks and troughs in the overall wavelength because I don’t want to ‘miss out’ on exciting any pigments.

 

[taricha]

A fixture with 420 and 450nm LEDs look exactly the same to my eyes.

I can visually see definite differences between the 422nm, 451nm and 468nm LEDs.

Oh no. I guess I'm blue-blue colorblind! [emoji1]

As a follow-up, these two blue LEDs are closer than the manufacturer description. They are 430 and 448nm.

I asked my students if any of them could see a difference in the blue LEDs. Probably 80% (like me) said they look exactly the same - blue, no matter how they tried. But a few students said very specifically that the center one looks a little more purple. My samsung galaxy s7 (where the pic came from) also renders the 430nm as clearly more violet.
[...but a newer samsung galaxy renders both LEDs as equally blue - to match the less accurate vision of the majority!]

 

[Jase4224]

As a follow-up, these two blue LEDs are closer than the manufacturer description. They are 430 and 448nm.

I asked my students if any of them could see a difference in the blue LEDs. Probably 80% (like me) said they look exactly the same - blue, no matter how they tried. But a few students said very specifically that the center one looks a little more purple. My samsung galaxy s7 (where the pic came from) also renders the 430nm as clearly more violet.
[...but a newer samsung galaxy renders both LEDs as equally blue - to match the less accurate vision of the majority!]

Interesting, I assumed that everyone would see that the colours are different. I know women tend to see purple when Men see blue. I once had a blue damsel and every woman who saw it said was purple but all the guys thought it was blue. There is no ‘actual colour’ I guess.. just and individual brains interpretation of wavelength.