How To Make a Pseudo HDR

Pseudo high dynamic range photos are really nothing more than a single exposure processed as an HDR. There are other guides on how to do this but I am going to describe the process I’ve found that I think works pretty well, at least in my humble opinion. This little guide assumes nothing about software, but points out principles I think may help enhance your pseudo HDR experience.

The first thing you’ll want to do is select or take a good candidate photo for processing.

  • A good candidate photo should be well exposed—that is there are not a lot of blacked out or burned out spots on the image. HDR images attempt to prevent this from happening by merging images together. Just about any image that is well exposed can be used, although you may be able to get away with a poorly exposed image.
    • If you look at the tone curve below, you see two peaks and a valley. If the tone curve contains peaks or valleys that are flat, then the image is probably blacked out or burned out.
    • Most cameras nowadays have a way to see the tone curve while you are shooting the image, or right after you’ve shot the image.
  • If possible, shoot the photo in a RAW format so that the camera does not do any processing to the image.
  • You’ll want a low ISO too.

I shot this image at as a RAW file at ISO 100. This is the image with no processing save a resize and conversion to a JPEG, but even conversion to a JPEG does  alter it some.

Pseudo HDR Original Image
Pseudo HDR Original Image
Flat Tone Curve
Flat Tone Curve

The next step you’ll want to do is to “flatten” the image. An image that is flat is an image that seems to lack contrast such that the colors look washed out. The human eye has a tendency to gravitate towards localized contrast, and images that don’t have such are typically described as flat. RAW images right off a camera almost always look flat without some sort of post processing. Images converted to JPEG usually go through some sort of algorithm to make the image look more natural, typically done by adding more contrast. The white line represents the bias by which the photo processing software is altering the photo. This line is straight (i.e. flat) while the human eye sees things in more of an “S” shape with the line flattening out at the top and bottom.

  • If your image is flat already, you may not need to do any post processing.
  • If the image has light and dark areas you may want do some post processing to flatten the image more.
  • Add fill light if there are dark spots. You may want to decrease the overall contrast of the image and tweak the brightness some.
  • If the image was shot at a high ISO, you’ll probably want to run a noise reduction algorithm to smooth this out some. Some HDR processes can really expose noise even at low ISOs.
Pseudo HDR Flattened Image
Pseudo HDR Flattened Image

Once the image is flat, you’ll want to save it as a 16 bit TIFF or something that supports a higher bit range than 8 bit because tone mapping attempts to compress higher dynamic range images into lower range images, typically by reducing the color information. 16 bit TIFF files store enough information for most modern cameras.

After saving the image, you can process it like any other image that was produced using HDR, so fire up you’re HDR program and start tweaking the image with tone mapping!

Pseudo HDR Image
Pseudo HDR Image

After I ran this image through Qtpfsgui (a free HDR workflow), I rotated and cropped it some to come up with this image.

Pseudo HDR Final Image
Pseudo HDR Final Image

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