Using Curves in HDR Processing

Article by Malcolm MacGregor

If I were to suggest just one tool for you to learn in photoshop, it would be the Curves tool. The curves tool is an extremely powerful tool. It’s able to increase contrast, saturation and can even change the color balance of your image. It is, by far, the tool I use the most in my HDR processing workflow.

Let’s talk about how I used the Curves tool to process this photo of the Okaloosa Island Fishing Pier in Ft Walton Beach Florida.

This photo is a 6 exposure HDR, merged in Photomatix. Generally, when I merge my exposures in Photomatix, I try to keep them looking pretty flat. I always want to make sure that I am doing the bulk of my processing in Photoshop. So here is the photo after merging in Photomatix:

 Now I am ready to begin with my curves adjustments. The first thing I do is to break the photo up into sections. This photo has 3 main sections:

  1. Water and Sand
  2. Pier
  3. Sky

I create curves adjustment layers specifically for these individual areas using masks on the adjustment layers. If you don’t know how to use masks, I highly recommend you look it up! It’s actually very easy and allows you to apply adjustments to specific parts of a photo.

Lets start with the Water and Sand areas. The first curves adjustment layer I did looked like this:

I then did another curves layer for the sand only (masking out the water portion) to brighten it up even more:

 

My next curves adjustment was for the small area where the water was splashing against the pier. I wanted the splashes to really stick out, so I lightened them up a bit more:

The last curves adjustment layer I did on the sand/water portion was to add tones to water. I changed the drop down box that normally says “RGB” to “Green”. This will allow us to affect the green channel only. By pulling the top right point straight to the left, I add very subtle green tones to the water:

Now that I’ve got the sand and water looking the way I want, I’ll start on the pier. I only did one curves layer for the pier, to brighten it up and add lot’s of contrast:

The next section of the photo to work on would be the sky. I did 3 curves adjustments for the sky, 1 for contrast and 2 for toning:

Red Tones:

Blue Tones:

And this completes the curves adjustments! Leaving us with the final photo:

 

You can see we’ve made quite a transformation from the original. The final photo has much more saturation and contrast without looking overdone. We were able to pull a lot of detail and color out which makes for a more dramatic presentation. Some things to keep in mind:

  1. Not all of your curves adjustments will look the same. This is the point of masking, so you can apply different adjustments to different portions of the photo.
  2. Take your time with the masks. Sometimes it is useful to use a plug-in such as Topaz’s Remask. Remask makes it easy to get very clean selections.
  3. You’ll see that when you increase contrast with curves, you’ll also increase saturation. If the saturation is too much for you, change the blend mode to “Luminosity”. This will allow the curves layer to keep the contrast, but not the saturation.
  4. Experiment and have fun!

Here are some other photos where I’ve used multiple curves adjustment layers:

 

 

I hope you’ve found this curves tutorial useful! If you have questions, feel free to email me at malcolm@sohdr.com

You can find more of my work on my website photomalcolm.com

You can find more info on HDR and even watch full in-depth HDR tutorials at schoolofhdr.com

  • http://www.facebook.com/john.miguez.3 John Miguez

    Very nicely described. Thanks.

  • ZeeKay

    Wow! You have said a whole lot of nothing here.

    Let’s see, we do not have access to your original files so we can play with it and see for ourselves what you did. You have not shown step-by-step progression of your image after each adjustment. You also haven’t talked about in any useful detail on what each adjustment does and your thought process in doing one way or another.

    I am a Photoshop power user and I also use Curves a lot. The only take away for me is to try to use some of your adjustments to my images and see if they become interesting. Sort of like, let’s see if this does something cool to the image.

    Really, what is the point of this article? Zero points for any useful information.

    • ZubbuZ

      Seriously, care to whine and whinge some more?

      It was a good article/tutorial to make people aware of the feature (who have never really used curves before) and give them an idea of what it can do… It never claimed to be an in-depth piece detailing every little step. If that is what you (or others) want, then there are other tutorials out there…

      Grow up dude…

      • ZeeKay

        Ok so you are “aware” of curves in general now. But what useful information did you really get out of it besides being “aware” of it?

        Can you now apply them and decide what curves adjustment would work? I bet you have to try a lot before you get a hang of it and then spend a lot more time to be able to assess where it would make sense.

        There are a lot of tools in PS that you may not be aware of. I suggest you start with a good tutorial first.

        The author clearly did not share his technique in any useful detail.

        • ZubbuZ

          Oh, I was aware of curves before this. But awareness is the first step to learning anything new. When I come across something new, it is often at a mere mention of information and how it can be useful, then if I am really interested I can easily go do further research.

          This isn’t really a site that does massively in-depth tutorials. What you are saying is that no one should ever mention a topic to anyone unless they are prepared to sit down and go through the entire thing step-by-step holding your hand… That’s just stupid…

          Malcolm will have just done this out of his own time, and if makes people aware of what curves can do, then it has done its job…

          I maintain my previous thought – grow up.

          I hope you have an entire website that you upkeep yourself, with massively in-depth tutorials for everyone to read. Either that or you better never mention anything you know to other people otherwise you might be guilty of ‘only’ making people aware of information… We wouldn’t want that now would we…