# Hair color in infrared....



## sarahashleyphotos (Aug 2, 2009)

I figure yall could help me with this. 

First of all this is about these images: 






Someone had told me that since my hair is dyed red it should have been a different color in IR. "I did read the part about your hair being red and if you know anything about IR, you know that dye has a much different IR reflectivity." I was just wondering if I am doing anything wrong. My custom white balance was set for grass and this was shot with studio flash lighting. Im not familiar with the science of IR but it looks right to me. He also said stuff implying that the shots being underwater would have some effect on the IR. "I am quite familiar with IR photography but it is still a fairly new medium that I have not seen that much underwater". & This really through me "I am not sure how the IR relates to how they turned out. It would be interesting to see if there really is a difference in IR or not, did you take any non-IR shots?" lol My hair is not blue in real life so ya there is obviously a huge difference.

Also this really confused me: "I have found usually quite different techniques between IR photographers and physics have a habit of cropping up when you are using beyond visible." He kept bringing up physics and I dont know what that has to do with IR at all.


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## UUilliam (Aug 2, 2009)

sarahashleyphotos said:


> He kept bringing up physics and I dont know what that has to do with IR at all.



Now this bit i can answer 
Physics has everything to do with IR
The Colour spectrum of which We can see (Visible light) and everything under the visible light spectrum (infra red) and everything above the visible colour spectrum (Ultra violet)
It's all about Wavelengths (&#955; - Greek letter Lambda - Symbol in physics for wavelength)
Basically what happened when the convert your camera is they remove the IR filter which all camera's have to stop Wavelengths Above and below our Visible Spectrum from showing up meaning the camera is constricted to a wave length of 380 - 700 nanometres (on average)

Infra red falls into 3 categories:



 IR-A: 700 nanometres - 1400 nanonmetres
 IR-B: 1400 nm - 3000 nm
 IR-B: 3000 nm - 1 mm
If you have ever heard of people speaking of people having different colours, Basically these colours which the body emits is too far beyond the USUAL wavelength that most humans can detect unaided, however we are not all the same, this is how some people can read your "aura"
Basically it is the heat which your body is emiting, If your in love, your body will be hotter than usual, If your sad, your body will feel fairly cold etc..

anyways thats what Physics has to do with infrared...


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## KmH (Aug 2, 2009)

sarahashleyphotos said:


> My custom white balance was set for grass and this was shot with studio flash lighting.


Here is a big part of the problem.


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## DeadEye (Aug 2, 2009)

ep its all physics!

 Think of it this way.  Color is a wavelength of light.  White light is a sorta mix of every color.

 Well what determines the color of an object?  Answer~ absorption .

 Why is an object green?  Answer ~  White light strikes the object and most of the red and blue wavelengths are absorbed thus a majority and the reflection to your eye is green.

Infrared is just another color all be it one we cant see with the naked eye. 

A pure infrared image is therefore monotone. 

 Why is there color in my infrared image?   ~    Visible light leekage.

Dan


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## DeadEye (Aug 2, 2009)

Look at the blue item marked in this thread.

Blue leeks the most on my conversion.

http://www.thephotoforum.com/forum/general-gallery/172271-infrared-photography.html


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## UUilliam (Aug 2, 2009)

DeadEye said:


> Infrared is just another color all be it one we cant see with the naked eye.
> 
> A pure infrared image is therefore monotone.
> 
> ...




your half right there...
Infra red isn't a colour, It is a class for any colours that have a wavelegth below Red


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## DeadEye (Aug 2, 2009)

UUilliam said:


> DeadEye said:
> 
> 
> > Infrared is just another color all be it one we cant see with the naked eye.
> ...



 Ok~ Thank You


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## sarahashleyphotos (Aug 2, 2009)

Ok. I dident have to take physics in high school so I dident really know what it was but I understand the whole wavelength thing. I also know what they did when they converted my camera. I guess my problem is my lights but really I dont see it as a problem... I like the outcome and think well it was taken with a camera that was converted to infrared well then that obviously is having an effect on the image so you cant say its not infrared. When I get the money ill buy some hot lights and see if there is any diffrence but I dont even see much of a diffrence when I photograph myself outside. My hair is just a little lighter than shown here.


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## UUilliam (Aug 2, 2009)

Tbh i like your out come too, And lights emit differently with infra red
heat emits Infrared colour too so the heat of the light will also change the outcome of the image.


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## Dwig (Aug 2, 2009)

sarahashleyphotos said:


> ...it was taken with a camera that was converted to infrared well then that obviously is having an effect on the image so you cant say its not infrared...



Did your conversion replace the IR cutoff filter with a filter that blocks the visible portion of the spectrum or was it done the usualy way where a clear glass flat replaces the cutoff filter. If done the later way, you camera still sees the full visible spectrum in addition to seeing IR. 

Even when a visible-cutoff filter is used as a replacement for the IR-cutoff, all photosites still see some IR regardless of whether they are assigned to the red, blue, or green channels. If you leave the image data in its default color mode, you will see some tint as the different red, green, and blue filters on the photosites are still present and don't transmit IR equally. There is no way to adjust this tint other than in post processing and the three color channels do not represent different sections of the IR spectrum to any significant degree.

Also, there is absolutely no way to predict the degree of IR reflection that an object has purely by its percieved visible color. Objects that appear to be exactly the same color visually, or when photographed with a "normal" camera, can have radically different brightnesses in the IR.


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## DeadEye (Aug 2, 2009)

sarahashleyphotos said:


> Ok. I dident have to take physics in high school so I dident really know what it was but I understand the whole wavelength thing. I also know what they did when they converted my camera. I guess my problem is my lights but really I dont see it as a problem... I like the outcome and think well it was taken with a camera that was converted to infrared well then that obviously is having an effect on the image so you cant say its not infrared. When I get the money ill buy some hot lights and see if there is any diffrence but I dont even see much of a diffrence when I photograph myself outside. My hair is just a little lighter than shown here.



 I dont see it as a problem either, its a charteristic of digital IR. I did not intend to say the image was not Infrared ,only to help explain the results.

 Dan


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## Garbz (Aug 3, 2009)

Your introducing variables that can not be understood by us. We don't know what your hair would look like emitting IR light. A spectrum analyser would be able to but we can't. The issue here is that different dyes emit different IR light, water absorbs IR light, and a studio strobe doesn't generate the same amount of IR as say a lightbulb (I think not sure about this last part).

No one can say for sure that your hair should or shouldn't have looked the way it does under your conditions, it hasn't been measured and it can't be seen. For instance take this picture:





It was on IR sensitive film with a 720nm filter so the only light here has the range 720nm to 850nm. Her hair is still the same brown as it always is, but her dark lips are as bright as the rest of her skin, and you can't tell that a very pale skinned girl is wearing a very very dark red jumper.


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## sarahashleyphotos (Aug 3, 2009)

Dwig said:


> sarahashleyphotos said:
> 
> 
> > ...it was taken with a camera that was converted to infrared well then that obviously is having an effect on the image so you cant say its not infrared...
> ...



No clear glass. A IR filter was put in place of the IR block filter which was removed. My conversion was done by lifepixel.com.


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## blash (Aug 3, 2009)

Garbz said:


> It was on IR sensitive film with a 720nm filter so the only light here has the range 720nm to 850nm. Her hair is still the same brown as it always is, but her dark lips are as bright as the rest of her skin, and you can't tell that a very pale skinned girl is wearing a very very dark red jumper.



Now her eyes are creepy though


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## Dwig (Aug 3, 2009)

sarahashleyphotos said:


> ...
> No clear glass. A IR filter was put in place of the IR block filter which was removed. My conversion was done by lifepixel.com.



Then unless you had a visible-cutoff filter over the lens, like the one mentioned in Garbz's reply, your shot is not pure IR. Its a mix of IR and visible. Nothing wrong with that, per se, but its a bit of a different effect than that of pure IR.


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## Garbz (Aug 4, 2009)

Dwig said:


> Then unless you had a visible-cutoff filter over the lens, like the one mentioned in Garbz's reply, your shot is not pure IR. Its a mix of IR and visible. Nothing wrong with that, per se, but its a bit of a different effect than that of pure IR.



I think she meant "No clear glass", and not "No, clear glass". From my reading the IR high-pass filter is on the sensor.


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