Infrared is blue?

[Herb Cunningham]

I got a D20 that was modified for IR from my dealer, who is loaning it to me until I can decide on a camera to convert. When I take photos in the shade, I get pretty good IR response, i.e. foilage is white. When I shot some Kudzu in overcast light, foilage comes out blue.

I think I need to reset the white balance, but don't have a clue about how to do dat.

Thanks
Herb

 

[donbga]

I got a D20 that was modified for IR from my dealer, who is loaning it to me until I can decide on a camera to convert. When I take photos in the shade, I get pretty good IR response, i.e. foilage is white. When I shot some Kudzu in overcast light, foilage comes out blue.

I think I need to reset the white balance, but don't have a clue about how to do dat.

Thanks
Herb

Try doing a custom white balance.

Don

 

[pellicle]

Hi

I got a D20 that was modified for IR ...
I think I need to reset the white balance, but don't have a clue about how to do dat.

if its a Canon 20D then you photograph something which is "white" and then use that to set the white balance (its a bit odd in my opinion) but it its a D20 then I have no idea that it is or how to do it.

I also suggest trying different "filters" in the black and white settings ... Canon emulates orange / red / green filters in the camera ... alternatively shoot in RAW and fiddle back on the PC.

I'd convert to monochome and forget about the 'false colour' IR stuff ... but then hey, I'm a HIE fan and never tried the EIR films

 

[Worker 11811]

Infrared isn't really a color at all. It is a wavelength of light/radiation which is longer than (lower frequency than) what the human eye perceives as red. That's why it's called "INFRA-red" as in "BELOW-red." As such, infrared doesn't register as a color to the human eye and is typically perceived by the human body as heat.

Cameras (film and digital sensors) CAN detect infrared but they do not typically couple those wavelengths to the red part of the human-visible spectrum. They could couple to almost any color that they are designed to but they are often registered as a light cyan or bluish white color.

Try a little experiment. Take a picture of the emitter ("business end") of the remote control to your television, using a digital camera while you are pressing one of the buttons. You should be able to see momentary blue-white flashes of light coming out of the remote control. This will tell you whether your camera can register infrared and how well it registers it. It will tell you what color your camera will couple infrared to. It's also a good way to tell if the remote control to your television is working or not!

If you use a camera that shoots infrared or has been modified to shoot infrared, you will have to do what others above have said: white balance the camera so that infrared registers as white. (Or whatever color you want it to register as.)

Alternately, you could use Photoshop or GIMP to rotate your color palate around so that infrared registers as whatever color (white) and any other colors that register along with it are proportionately shifted to other colors.