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Photography Question 
Chris Macer

Merging images in PSCS2

Hi everybody, I've been experimenting with exposure adjustments in RAW recently. I'm wondering if anyone can give me info about merging images in PSCS2. I want to increase the overall dynamic range using 2 frames - i.e., one exposed for highlights, one for shadows.
Does anyone have any advice or know of resources on how to effectively do this? I know that has a plug-in for doing this. Any experiences with this one? Thanks in advance for any tips! :)

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4/26/2006 7:54:55 AM

Charlotte K. Lowrie   Hi Chris,
I haven't had experience with Fred's action or plug-in, but if you want to merge two processed RAW files in PSCS2, here are the basic steps.
*Be certain that you used a tripod to take both images. If there is the slightest difference between the images, this process won't produce good alignment for obvious reasons.
1. Open both processed images in PS CS2 and tile them so that you can see both images.
2. Click the Move tool in the Tool palette, and then hold down the Shift key as you drag one image on top of the other image. Then let go of the mouse key before you let go of the Shift key. This action precisely aligns the images.
3. Click the Layer mask icon at the bottom of the Layers palette. Be sure that the Foreground and Background colors in the Tool palette are set black/white (click the double arrow to reset them).
4. Be sure that the Layer mask is active, and then click the Brush tool (at whatever brush size is appropriate), and then paint using Back to hide the layer and white to reveal it.
5. Tweak as necessary. ;)
If you REALLY want dynamic range, try High-Dynamic Range imaging with RAW files!
Best regards,

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4/26/2006 2:09:50 PM

Dan C.
BetterPhoto Member Since: 12/31/2005
  Hi, Chris.

There are many methods to digitally merge, including manual painting, easy automatic, and with a plugin. There is a very easy way with no painting and it works pretty good. You can see an example of this here:

This was digitally merged.

Here's a good tutorial on how to do it. The easiest method can be done in less than 30 seconds (used on the building picture) with no painting.

The method that takes no plugins and no painting is the LAYER MASK method.

BTW, using digital blending you can increase dynamic range more than 2 stops. I have not test it, so I do not know and I don't want to debate the point, but using simple logig it would seen that if a camera had a dynamic range of 6 stops, digital blending may increase that to 10 or 12.

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4/27/2006 4:19:06 PM

Chris Macer   Thank you very much Charlotte and Dan! That's some great info that you have both provided.

It seems that there are 3 approaches to take when doing this. The first being the "painting mask", which I had suspected might be the best but most time consuming. The "layer mask" looks like it could save a lot of time in some cases. I'll be keen to give it a try. And lastly, Fred's Action.

I'll give these a go asap and hopefully will see some great results in the near future. Thanks again! :)

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4/27/2006 9:02:31 PM

Toni Allen   Hi Chris,

This guy has a great tutorial which may offer some extra insight for you.

Good luck with your experiments!

Toni Allen

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5/4/2006 4:17:26 AM

Steve Mescha
BetterPhoto Member Since: 1/22/2002
  LOL, looks like I'm not the first to think of Luminous landscape when I read your post! Hope you found some great tips there. It's an awsome site :-)

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5/4/2006 6:33:38 AM

Robert Sena   Chris:

I saw a demo of High-Dynamic Range where the photographer took 7 shots and merged them to get a fantastic result. You can see the details in shadows as well as have great hightlights. This is just a lead as my knowledge stops there.

Bob Sena

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5/4/2006 9:54:54 AM

Jim Smith   Here's a better way, in my opinion. Bring your second image onto a second layer above the first, and change the blend mode of the second layer to "Difference." Then, move the layer around until you get the picture as DARK as possible (since your blend mode is "difference," the images will be aligned when they "cancel each other out.") Then, once aligned, just flip your blend mode back to normal, and you're all set.

If wind or something caused your two images to be slightly different, or if there are any other differences, just throw a mask over whatever parts of the picture are NOT well aligned (e.g., where the image is NOT dark in "difference" blending).

If differences in specular highlights are noticeable (e.g., sun coming off of waves between the two images in a seascape), you could make the top layer a "Darker" blend mode, which would prevent those specular highlights from being duplicated.

This technique came from Jack Davis, by the way.


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5/4/2006 6:57:17 PM

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