UV Induced Infrared Fluorescence 2

[Stefano]

Yes, a monitor can only simulate most colors. Some colors, such as the red from a far red LED or the violet from a violet LED can't be shown as they really are. I once tried (and I will have to do this one day) to reproduce in Paint the colors of my LEDs as close as possible (my screen is an LCD, maybe OLEDs work better). The real, pure colors coming from my LEDs were like twice as saturated as the colors my screen showed. The difference was a lot.

 

There is also the issue that some cameras struggle with violet light, and show it as blue instead. A 405 nm violet laser pointer may appear blue using most cameras, especially if old, but newer ones do see it as violet. My phone's front and rear camera see a 405 nm laser pointer/LED in different colors.

[Cadmium]

There is the aspect of the RGB Bayer filters responding unevenly to IR until about 800-850nm, then they are more the same and thus the image becomes more monochrome.

The red Bayer filters transmit 700nm range stronger than blue and green Bayer filters do. Above 800 the red/blue/green Bayer filters tend to transmit the same.

So that is part of the IR color difference. You all know that already, just pointing it out for the balcony crowd.

 

http://www.astrosurf...esponse-ccd.jpg

 

http://www.astrosurf.com/luxorion/Physique/spectral-response-ccd.jpg

[Stefano]

...shouldn't red dominate in UV around 360 nm? We are talking about IR, but the UV region seems a bit off...

[colinbm]

Colin, the problem isn't the camera, the camera (as you said here) responds to indigo and violet wavelengths just fine. It's that the MONITOR can't display 400nm using an LED that peaks at 450nm.

 

Thanks Andy

[Cadmium]

Stefano, You are right, we are talking about IR.

There are a lot of those Bayer graphs, pic your favorite, they are all about the same, simply trying to illustrate the point that RED is stronger in the lower IR range.

[dabateman]

Ya that graph is off we should hand draw a better one. Blue cuts off generally at 380nm. Then green takes over. Red might bump back up again below 300nm, as once I got mostly red with a 280nm shot. But I don't know if my white balance was good.

[Cadmium]

This is what I mean. Several different filters options on this one 1000 diffraction grating.

 

My question is about the part with green arrows.

 

This is already cut off by a S8612. Also, the any camera with hot mirror no longer sees it.

 

But it is not yet 'false orange infrared'.

So how should I name this range correctly?

 

All the most beautiful flower stamens are here.

 

 

I got looking at this grating comparison again. I find this interesting, mostly the top no filter grating, then compared to the filtered gratings.

The top grating, showing the full spectrum range, blue, green, red, far red. and all the way up into monochrome IR!

I have NEVER seen that, or at least I never noticed that presented like that before. That one full spectrum grating is very revealing.

So to answer the question about what to name the #1 zone...? I am not a scientist, but there are some around here... Any ideas on the name, anyone.

Andy named a torch, so maybe he is good with names? Someone? Anyone?

Regardless, I really like that no filter grating!

 

[Stefano]

Usually the 700-750 nm or 700-800 nm region is called "far red". It is infrared by definition, but still has some of the characteristics of red light. Some objects become white but others are still dark, and it is also visible to the human eye as a very deep, strong, dull red color.

 

 

He says far red is not infrared. I disagree, but it is true that this band is in the middle land, and borders are blurry, as for UV and violet.

 

However, when he says it is the deepest red you will ever see, I 100% agree. It is PURE red, you really have to see it. A beautiful color, one of my favourites. You can get something similar by looking through an Hoya R72 or similar, but there's nothing like turning on a 10 W 730 nm LED in a dark room, and look at how your hands become red under the light.