Matt Grunau
Adobe Demigod
Here's a way to fake a thermal image in Photoshop. You can easily set this up to be an action, and then batch process many files, allowing you to use it for video. This is not infer red, where heat is displayed as white and cool temps are dark gray, this is basically how the Predator sees people in the Predator movies.
First, you will have to create a custom gradient. Select the Gradient tool, and then click on the gradient bar that appears under "Image" shown by the red arrow.
A new window will pop up. Click on the small boxes to the left and right on the gradient and you will have the option to change them.
Make the right one white and the left one dark blue. Then, by clicking in the gradient itself, you will create additional color spots. You can change them to any color you want by double clicking on them or by clicking on the Color on the bottom left of the window. Set up your new gradient as I have here. I just used dark blue, then B255, then a slightly darkened G255, then red, yellow, and then white. These are only the colors I picked; you can and should experiment and find ones that work for each clip you use. Then rename it (I named mine Thermal, but you can name it Aunt Susie or whatever) and click the New button, and you will see it appear in your gradient "list".
Now you need something to use it on, and what channel. So, open a picture. You will need to isolate a channel to get it to look its best. I usually choose the red channel, as its monochromatic values put red represented by white, and green and blue represented by darker colors. If you don't understand how colors are represented by this grayscale range or how they pertain to the mixing of R, G, and B in building an image, you need to. Every color is built from three mains; Red, Green, and Blue. The amount of these colors in 8-bit color is represented by 256 shades of gray, also called Luminosity. Sound confusing? Just load an image, and open up the Channels pallet and you will get it. With channels palles open, click on any one channel. You will see your image drop to grayscale, and as you click from red to green to blue, you will see the grayscale change. In each channel you choose, lights and darks represent the amount of that color. The more of each color there is, the lighter the grays become. An all green picture would have the green channel represented by pure white, and the red and blue channels would be black, since there are no other colors present. Think of it as a graphical representation by blending the "Saturation" of a picture and the "Layer Mask" function to show you how much of each primary is present. Whew, long paragraph.
Ok, so you need to isolate a channel. Why? Because it gives the cleanest results, and when you go to apply your Gradient map, you will need it. A Gradient Map works by applying a gradient over an image, based on lightness and darkness (among other things). So, by isolating only one channel in grayscale, you apply the Gradient Map to the lightness and darkness of its Luminosity, and get your effect. This is especially handy for flesh tones which are based in red, and therefore the red channel will have white where red is present, and dark where it is not. And, since skin gives off heat, isolating the red channel makes the most sense.
There are two ways to isolate the red channel, and either will work when setting this up and creating an action. You can go to Image>Adjust>Channel Mixer and check the Monochrome box in the lower left corner (the Monochrome by default will give you the red channel, but you can change which channel you want, and how much if you like) and then click OK. Or, you can go to the Channels pallet, click on the red channel, Crtl+A to Select All, then copy, click on RGB in the channels pallet to select all three channels again, and then go to your Layers pallet and Paste. The Channels route gives more accurate results. I don't know why, logically they should be identical, but the Channels way gives more contrast, which is good.
With that now on its own layer, you go to Image>Adjust>Gradient Map, and then choose the gradient you created, and then click OK. You should see your grayscale image converted to the gradient you made, and if you used the red channel, your flesh tones will have turned white/yellow/red.
Of course, if you have a lot of other red tones in your image, they will be affected the same as your skin tones, so you may have to prepare your shots correctly (like DON’T dress in a bright ass red shirt), or you may have to mask out regions of interest.
You can probably pull off something similar in After Effects or the like, but Photoshop gives more option and control. Of course, there are plugins that can probably do this, but they cost money, and you will have a better working knowledge of Photoshop and video by doing it down and dirty.
That's it. Cheerio, toodle pip, and all that, and have fun.
:thumbsup:
EDIT: Pics & Video before & after:
First, you will have to create a custom gradient. Select the Gradient tool, and then click on the gradient bar that appears under "Image" shown by the red arrow.
A new window will pop up. Click on the small boxes to the left and right on the gradient and you will have the option to change them.
Make the right one white and the left one dark blue. Then, by clicking in the gradient itself, you will create additional color spots. You can change them to any color you want by double clicking on them or by clicking on the Color on the bottom left of the window. Set up your new gradient as I have here. I just used dark blue, then B255, then a slightly darkened G255, then red, yellow, and then white. These are only the colors I picked; you can and should experiment and find ones that work for each clip you use. Then rename it (I named mine Thermal, but you can name it Aunt Susie or whatever) and click the New button, and you will see it appear in your gradient "list".
Now you need something to use it on, and what channel. So, open a picture. You will need to isolate a channel to get it to look its best. I usually choose the red channel, as its monochromatic values put red represented by white, and green and blue represented by darker colors. If you don't understand how colors are represented by this grayscale range or how they pertain to the mixing of R, G, and B in building an image, you need to. Every color is built from three mains; Red, Green, and Blue. The amount of these colors in 8-bit color is represented by 256 shades of gray, also called Luminosity. Sound confusing? Just load an image, and open up the Channels pallet and you will get it. With channels palles open, click on any one channel. You will see your image drop to grayscale, and as you click from red to green to blue, you will see the grayscale change. In each channel you choose, lights and darks represent the amount of that color. The more of each color there is, the lighter the grays become. An all green picture would have the green channel represented by pure white, and the red and blue channels would be black, since there are no other colors present. Think of it as a graphical representation by blending the "Saturation" of a picture and the "Layer Mask" function to show you how much of each primary is present. Whew, long paragraph.
Ok, so you need to isolate a channel. Why? Because it gives the cleanest results, and when you go to apply your Gradient map, you will need it. A Gradient Map works by applying a gradient over an image, based on lightness and darkness (among other things). So, by isolating only one channel in grayscale, you apply the Gradient Map to the lightness and darkness of its Luminosity, and get your effect. This is especially handy for flesh tones which are based in red, and therefore the red channel will have white where red is present, and dark where it is not. And, since skin gives off heat, isolating the red channel makes the most sense.
There are two ways to isolate the red channel, and either will work when setting this up and creating an action. You can go to Image>Adjust>Channel Mixer and check the Monochrome box in the lower left corner (the Monochrome by default will give you the red channel, but you can change which channel you want, and how much if you like) and then click OK. Or, you can go to the Channels pallet, click on the red channel, Crtl+A to Select All, then copy, click on RGB in the channels pallet to select all three channels again, and then go to your Layers pallet and Paste. The Channels route gives more accurate results. I don't know why, logically they should be identical, but the Channels way gives more contrast, which is good.
With that now on its own layer, you go to Image>Adjust>Gradient Map, and then choose the gradient you created, and then click OK. You should see your grayscale image converted to the gradient you made, and if you used the red channel, your flesh tones will have turned white/yellow/red.
Of course, if you have a lot of other red tones in your image, they will be affected the same as your skin tones, so you may have to prepare your shots correctly (like DON’T dress in a bright ass red shirt), or you may have to mask out regions of interest.
You can probably pull off something similar in After Effects or the like, but Photoshop gives more option and control. Of course, there are plugins that can probably do this, but they cost money, and you will have a better working knowledge of Photoshop and video by doing it down and dirty.
That's it. Cheerio, toodle pip, and all that, and have fun.
:thumbsup:
EDIT: Pics & Video before & after:
Last edited:
Trying it out now.
