FX-Foundry’s Dynamic Range Extender: Fixing photos with bright skies

October 14, 2009

I recently discovered something really cool in the FX-Foundry plug-in pack for Gimp. Have you ever taken a photo that was exposed properly for the sky, but then everything in the foreground was really dark? Or you exposed properly for your subject but the sky was blown out? Like… say, this photo:

Essentially SOOC

This is the image converted directly from RAW to jpg with no adjustments. As you can see, the sky’s a bit blown out – especially near the tree branches – and the building is a bit dark, especially at the bottom.

The important part is that you have two versions of your photo – one that’s exposed correctly for whatever is bright (like the sky in this case) and one that’s exposed properly for what is darker (the building, in this case).

There’s a few ways you can do this:

  • Use a tripod and take two photos. This is the best way to go if you’re taking a photo of something completely still – like this landscape. I, unfortunately, didn’t do that.
  • Shoot in RAW and use your RAW editing program to give you two different exposed photos – this is what I’m doing with this photo.
  • Shoot in jpg and edit the photo – this is the last choice, as far as I’m concerned. There are definitely reasons to shoot in jpg – and some cameras only allow you to shoot in jpg – so at the end of this entry, I’ll give you some tips on how to get your two images when shooting in jpg

So. Here’s my two images that I got from my RAW editing program (once again, I’m currently using UFRaw, which is a free program that you can install as a plug-in for Gimp, which is why I use it, but since I haven’t tried any others yet, I’m hesitant to recommend it as a Raw editing program of choice):

Exposed for Building Exposed for the Sky

Here comes the most important part when using this filter: You must have two layers in your image and the bottom layer has to be the lighter one (exposed for the building, in this case) and the top must be the darker one (exposed for the sky):

My Layers

Now all you have to do is run the filter found under FX-Foundry –> Photo –> Enhancement –> Dynamic Range Extender. Here’s the dialog box you’ll get:

Dialog Box

So far I’ve just used the defaults every time and not had any problems. In this case, I end up with this final image:

Final Image

For comparison, here’s the original again:

Essentially SOOC


Tips for JPGs

So. You’re shooting in jpg only and your image is properly exposed for the sky? Try this to get one properly exposed for the building: In Gimp, create a duplicate layer and then set the blend mode to Screen. Still not light enough, do it again. As soon as you get too bright, just set the opacity lower on the final layer until it looks about right. Here’s my “Exposed for Sky” image with two duplicate layers set to screen mode – the top-most one is only at 70% opacity:

Using the

After it looks good, right click on the top layer and select “Merge Down”. Keep doing this until all your Screen layers have been merged down (note: if the only layers you have are the original layer and your screen layers, you can also do “Flatten Image” – which gets rid of ALL your layers and just gives you one layer that looks like exactly what’s showing in Gimp right then).

If you’re image is properly exposed for the building, the technique is the same, just use the Multiply blend mode instead of Screen. Note: this often does not give you great results – in fact, it looked like crap when I tried it with this image – the problem is that if something is blown out, it’s really hard to get those details back. So, if you’re shooting in jpg and you think you might want to try this technique, be sure to expose for the sky and not the building (or land, or whatever you’re shooting)

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  • FX Foundry looks interesting. I will be trying this out over the weekend. Some of the plugins that I use regularly are the ATM (Advanced Tone Mapping) plugin, the Lomo plugin and the Exposure Blend plugin for differently exposed shots of the same thing.

    Although I am now looking to use the Blending plugin slated to be released for digiKam. It looks quite good.

  • Laura

    I have been trying to figure out how to do this for so long! Sweet!

  • Pawel Maczewski

    Great job reviewing and posting info about this plugin ;) This is something I've been looking for - simple yet powerful. I always got scared with number of settings in any HDR-related software (and I'm not a person that gets scared by number of settings easy, just I couldn't get any results I was hoping for...). I tried this plugin and it worked! Thanks a lot.

  • @Pawel
    If you use GIMP, try the ATM plugin. If it so much better than HDR software like Photomatix in giving you that extended exposure range.

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