Creating Simulated Infrared images
History:
Infrared is an intriguing view of objects we see every day in a new light. That is of course because the infrared region is outside normal human vision. Many use converted digital cameras that see infrared to make images that look out of this world. When we talk about infrared there are often terms that get mixed together in ways they shouldn't. For instance many people think of thermal images when they hear the words infrared. Thermal is the longest parts of the infrared spectrum and generally not part of popular photography. Infrared is really divided into a few categories having different properties. I won't geek this out much beyond quickly separating these terms. This tutorial will show you how to do both a NIR and an MWIR image.
- Normal visible spectrum looks from .4 to .7 microns (also said as 400nm to 700nm) common camera detection range.
- The Near infrared (NIR) region is from 0.7 to 1.1 microns (also stated 1100nm and the upper detection limit for silicon based cameras)
- The Short wave infrared (SWIR) band is from 1 to 3 microns (non-thermal and above hobby camera detection, sees through smoke)
- The Medium wave infrared (MWIR) band is from 3 to 5 microns (thermal)
- The Long wave infrared (LWIR) band is from 8 -12- 14 microns (thermal)
1) Go straight to NIR GIMP tutorial - click here
2) Go straight to Color NIR Photoshop tutorial - click here
3) Go straight to MWIR Photoshop tutorial - click here
It was recently that I viewed a couple of NIR tutorials and they appeared to have lost a great deal in translation. They turned everything a weird purple and then titled it Infrared. The colors they create do look like some hobby photos. However, I think they missed what Infrared is supposed to do when done best. That is to alter the colors of plants and not make everything look like a psychedelic concert poster. Black and white Infrared was popular during the film era. Now the new fad is color-Infrared and this tutorial is aimed to emulate that appearance. Color IR is where vegetation is assigned color in different fashions by the infrared photographers via filters and a variety of other ways. One can always gray-scale the final image for the older film look. The main feature of NIR images is chlorophyll in plants. They reflect all the infrared light and so plants get distinguished easily when in the NIR. That is why the leaves of trees show so bright in Infrared. Yet the trunks of the trees remain dark toned. When you see a photograph that you suspect as infrared then check the vegetation to see if dark green vegetation such as pine trees are of light tone. Back in the very old days of film, the infrared showed up on the film because our forefathers didn't know what it was. Later cameras began to put filters into the camera to block infrared so it wouldn't disturb your normal images. When you see old photographs the people often have a sort of glow to them. Also the trees and so forth are light in tone. This is an infrared effect!
In essence this simulation is trying to create this effect. In the end this tutorial is not perfect and is just a simulation. The blossoms on the roses in the flower images are red even after the tutorial. In true infrared the red petals would also change color drastically given that they too are vegetation. So have fun but this is just a simulation and you may learn some cool stuff about layers in your favorite program.
Above is an actual infrared image of red roses
***********************************************
Click here to Download GIMP v2.4.5 by Spencer Kimball
***********************************************
If you don't have Adobe Photoshop for my tutorial below then download GIMP from the link above as it is free and powerful. It has similar features and you will be able to create the same type of Infrared looking images with perhaps additional creativity.
1) Left-click the File menu and Open your favorite flower or vegetation picture in GIMP. One of the problems you'll want to avoid is using an image that is already over-exposed. In other words, if the sky or any other part of the image is "blown-out" this process will exaggerate it.
2) In the image window under the menu Dialogs choose Layers. This window will show you the status of the layers we’ll use.
3) Right-click on the Background layer and choose Duplicate Layer.
4) Left-click the layer titled Background copy. On the image wondow under the Colors Menu, left-click Components and then sub-menu Channel Mixer.
5) In the Channel Mixer assure the Monochrome checkbox and the Preserve luminosity checkbox are checked.
6) Change the red input box to 110.0, the green box to 110.0, and the blue box to -120.0. Left-click OK to accept changes.
7) In the Layers pallette Left-click the layer titled Background copy and change its opacity with the slider above to 50% or some value where you think the colors look interesting.
8) Optionally you may want to right-click the layer titled Background Copy and choose Duplicate layer again. Change the Layers Mode to Screen in order to lighten up the image. Lower the opacity in the layer pallete if this becomes too bright. Consider adding yet another “screen” layered mode until the image is lightened to your satisfaction.
9) On the image window choose the menu File and Save As for the infrared simulation. GIMP will ask you to Export it and that will help flatten the file to a normal JPG to share with your friends. Use caution when left-clicking Save because this will overwriting your original file.
1) Open your favorite flower or vegetation picture in Photoshop
2) In the program menu choose Layer >> New Adjustment Layer >> Invert
3) Choose the OK button to accept the new layer
4) In the Layers palette set the Blending Mode to Color (on that palette it's a pull down menu that says NORMAL by default)
5) Select the background layer in the layers palette and in the program menu at the top of Photoshop choose the Layer >> Duplicate Layer
6) Choose the OK button to accept the new layer
7) In the layers palette move the background-copy layer to the top of your layers by dragging it up the layers palette. It will then be above the adjustment layer (called invert) you made earlier
8) Make sure that the background-copy layer is still selected and then change the blending mode to Screen
9) Save your results to a new file. The vegetation should appear more infrared or white looking at this point. Saving as a JPEG file will merge of all the layers you see and make a single nice image.
Optionally you may also want to bring only the background-copy layer's opacity down to 92% or similar using the layers palette option. Here is one more cool trick. A friend turned me onto .AHU files. Basically when you are in Photoshop hold the CTRL key while pushing 'U'. This brings up the presets for Hue, Saturation, and Brightness. You can play with this and save/load AHU files. Perform the Ctrl-U in Photoshop after you have your picture up. Then load in this file of mine and see what you think. Download Tracys_IR.ahu here. You can change this and save it off as a file to your own liking.
Congrats on finishing these steps!
To achieve the older style infrared film appearance change the image to gray scale, add some noise, and then maybe add edge glowing with filters from Photoshop or whatever you use.
This tutorial to a minor degree works on people. If you see human bodies in true NIR photographs they have a sort of waxy and soft glowing appearance. Much of the IR bounces back off the skin. People take on a pale appearance that to me isn't flattering. Usually the darker the skin tone the less ghostly they look. What stands out to me most in NIR pictures of people is how their eye-lids reflect so much NIR light. We are used to seeing slight shadows where the eye-lids are. However, the instructions will lighten up their skin and make some really interesting images. Also try swapping the red and blue channels for additional effects.
Care to see what people really look like in the NIR? Click{{HERE}}
For some non-scientific thermal images of people try this:
1) Load up your favorite people picture into Photoshop.
2) Go up to the menus Image>>Adjust>>Gradient Map. When the gradient map comes up click on the pulldown menu and choose the rainbow colored gradient. It is called 'spectrum'. Left-click OK to accept changes.
3) Since this is supposed to be a thermal image we can assume the skin should be warm. In thermal this might be best false colored red. If the skin is not red choose the menus Image>>Adjust>>Invert.
There will be incorrect heat signatures in the scene such as very hot walls or whatever, but this is only a fun simulation and beats buying a $9,000 thermal camera with low resolution.
People shown in simulated thermal infrared
To give you a reference of what your thermal simulation should look like, here is an actual thermal infrared image below. Notice the warm skin. The drink being held is a foam cup with ice. If you look closely you can see finger prints on the foam cup where it was previously held. The nose is actually cooler because it was cold outside right before the image was taken. The finger tips are colder because they were holding the icy cup earlier. The software for thermal can assign these false colors anyway desired. However, it's easier for most of us to grasp that shades of red are warm and blues are cold and so they are assigned that way. Thermal can also be gray scaled. In this instance the operator decides if the blacks or the whites represent warmer surfaces.
An actual thermal infrared image of the author
Written Dec07 and updated Nov09 by Tracy Rose