How to Produce Fake High Dynamic Range (HDR) Images
For years I have been interested in High Dynamic Range images. These images display a greater dynamic range between the lightest and darkest areas of an image. Most images have a dynamic range of about four to five f-stops. HDR images can be a range of 10 f-stops or greater. Photographers create HDR images by photographing a scene taking multiple exposures at a normal f-stop, but also at two to three f-stops underexposed. This process is called tone mapping and the images are merged in Photoshop or GIMP into one image with an expanded dynamic range exhibiting greater luminescence and detail. GIMP has a neat plug-in script called Fake HDR that allows you to expand the dynamic range without going through the rather challenging tone mapping process. Read on to learn how to create HDR-type pictures using Fake HDR for GIMP.
*Keep in mind this is only suitable for some images and the results are not really HDR, but the effect that you can obtain is stunning.
- Difficulty:
- Moderately Easy
Instructions
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1
Open Script-Fu
Ensure that the hdr-eff-plus.scm file that you downloaded for the Fake HDR script is in the SCRIPTS folder before opening your test file on GIMP. This can be found at //user/application support/gimp. All scripts are stored in this folder. The scripts can be downloaded from the GIMP Plug-In Registry. After you open GIMP, click on the Sript-FU tab to select the tools.
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2
HDR Effect
Try the HDR EFFECT. This only allows you to adjust the black layer opacity, and as you can see, when using it full strength (50) it makes the image look like a cartoon. Yes, there is more detail, but who cares? You can adjust this to lessen the effect.
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3
HDR Toolbox
Use the FAKE HDR EFFECTS PLUS. This allows you to adjust a lot of parameters in addition to black layer opacity. You can adjust the brightness and sharpness of the soft glow effect, which expands the dynamic range of the image. You can also adjust the saturation of the image and the level of image you want in the minimum and maximum portions of the image. Unfortunately, there is no preview, so you need to render each image and undo to begin to test the range of this tool.
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4
Adjust First
Adjust the saturation and brightness levels first; this will be helpful. Then adjust the dark layers and sharpness. I did this many times undoing each effect and testing the minimum and maximum levels to get an idea of what each slider actually controlled in the image.
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5
This is the final image for now. I want to spend some time testing this application and see if I can improve the result. I like the improvement in the detail and the saturation of the colors, although I feel they might be too saturated. I also think I want to shoot an actual HDR of a scene and use the "normal" exposure with Fake HDR and then compare the results. I think I still have a lot more research and writing to do on this subject, so stay tuned.
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Tips & Warnings
You have to download the plug-in and have it in the correct folder to gain access to the tool.
