Orionath

I don't quite have the hang of this yet. It's a little harder than the Contrast Masking technique. But these latest ones are getting close to acceptable so I thought I'd share my trials and progress. There are various photoshop tutorials on this. I like this one on Luminous Landscape the best.

I'm using Gimp instead of Photoshop. The original images were JPEGs, but I am doing the work in the Gimp native format since JPEG doesn't support transparency. I set my camera to take automatic bracketed exposures +- 0.7. I think that next time I will try +- 1.0 or +- 1.3 since the 0.7 setting didn't produce quite enough of a range. I used a tripod with AV priority at f-8 and 1/30 sec. I got three images: one slightly underexposed, one normal exposure and one slightly overexposed. I discarded the normal exposure and opened the light and the dark images. I did a Select - All, Copy on the dark image and then closed that window. Then, I opened the Layers and Channels dialog box and created a new blank layer using the light image as the background, pasted the clipboard contents (the dark image) into the new layer and named the layer "Mask". Next I added a Layer Mask to the new "Mask" layer. Then I clicked on the Background layer (the light image) in the Layers and Channels dialog box, did Select-All, Copy and then Pasted that into the new Layer Mask. With the Layer Mask thumbnail still selected, I applied Gaussian blur with a radius of 30 pixels and set the Opacity to around 80% to 90% (if my original images had had more of an exposure range, I would have started around 70%). Then I selected the Background image layer again and tweaked the contrast and color balance using the Curves dialog. Once I got as much as I was going to get out of my adjustments, I flattened the layers and resized the image.

One of the reasons for going through this layering and blending process is to help decrease the digital noise in low light photographs, but I noticed that there was still quite a bit of noise left (maybe because I had used only a 1.4 stop range in my bracketing instead of a 2 - 3 stop range). So I did some work with Gimp's Non-Linear filters. First pass through, I used Alpha Trimmed Mean (Alpha = 0, Radius = 1). That took out quite a bit of the remaining noise. Then Optimal Estimation (Alpha ~ .90, Radius = 0.66). Finally a couple or three passes with Edge Enhancement (Alpha = .40, Radius ~ .60). The result is similar to using Unsharp Mask except that the process also reduces noise similar to using Neatimage (tm).

I know that these aren't quite ready for prime time, but here are the ones that turned out the best. This is sunset 8/2/2003 from the overlook at Oswald West State Park between Neahkahnie Beach and Cannon Beach, Oregon. It was hazy and there was a thick fog bank offshore.

This one was pretty straight forward as I described above:


This one, I hand painted the ocean in the mask layer to reveal a bit more of it:


This one was pretty un-interesting until I inverted the color (image > color > invert) on the mask:


These all look darker to me on my work computer than they do on my home computer. I don't know if my home monitor is set too bright / too cool or if my work computer seems dark because of the flourescent lighting. If they look too dark to you, let me know.

I feel like apologizing for such a long post. I'm still trying to work through the process for doing this. If anyone has had good success with this type of blended images, please share your techniques and results.

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sta500

Real friggen' dark. I can't see anything but the sky, except for in the first one.

timberwolf5480

they are a tad bit dark, especially the last one.

Orionath

Thanks, sta500 and timberwolf5480. I think I will need to check the gamma or color temp on my home computer, then.

__________________
What awful irony is this?
We are as gods, but know it not.
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