Well it’s about time we hit the HDR. If you think we’re talking about some sort of Hardcore Digital Revolution, read on…
What we’re talking about is High Dynamic Range. This is one of the many great advances made in our software technology and most importantly, it’s sitting in Photoshop waiting for you to put it to use.
For those of you who haven’t experimented with HDR, there are a few things we should explain first.
For most people, editing your images in Photoshop usually involves either an 8bit or 16bit image. Which is fine for most everything we do.
However, there are some situations where there is such a dynamic range of luminance values, that it is impossible for us to capture everything in the scene.
Lets say you have a room lit with tungsten lighting(regular ol’ light-bulbs) and some deep shadows in certain areas, but you also have a window in the scene and it’s casting sunlight into a portion of the room.
Now just from this description we can imagine a scene with a wide range of values, not to mention some unbalanced lighting. We’re not gonna worry about the unbalanced lighting, that’s for another tutorial. But we are going to worry about our wide range of values in our lighting.
First we are going to bracket the scene. I would highly recommend your camera being firmly mounted on a tripod for this. If it moves at all or if your aperture changes, we will have problems.
We are going to bracket a series of exposures each designed to capture our dark shadows, along with our bright highlights. You can combine many images, but one thing to remember is we will be dealing with large files and serious processing, so if you are using on an old dog of system, might be best to start with three or four exposures first. Whatever. The point is to get some images that cover some range and we are going to mash em’ together in Photoshop.
When we bracket these we will also want to shoot at 1-2 stop exposure increments. Anything less is really ineffective.
After we have downloaded our multi-exposure experiment, our next step will be to find our images in Adobe Bridge and highlight them. Then in the tools menu up top we will select Photshop from the menu and choose Merge to HDR.
What this does is processes our images together and opens a preview window.We can mess around here with the white point preview, but I just always click OK.
After you process the image it will open in Photoshop. Now if you go up and select Image and then Mode, you will notice we now have a 32 bit file.
This is where we start the work. A 32 bit file contains an immense amount of data and for us that is a good thing. When configuring the data, it uses floating point math calculations instead of whole numbers when describing luminous values. So it really is using a different image mode to discern light values.
We now are given the flexibility to make some large adjustments to the image and since we have gone up to File and then Mode, we will want to change this to a 16 bit image.
What this does is brings up a HDR conversion window and from the drop down list we are going to select Local Adaptation. When this opens we click on the Toning Curve and Histogram arrow. Now we can adjust this image just like we would in Curves. The Radius and Threshold sliders can be adjusted and you should spend some time playing with them to see how they affect the image.
So that’s about all there is to it. Once you’re done click OK, and you now have a 16bit image that you can edit further in Photoshop.
You will see that it may be easy to go overboard on the adjustments and really tweak the image around. However the goal should be to create as natural looking image as possible. One that looks like minimal editing may have been done.
So have fun and see what sort of new doors this may open for you.
Also there are other HDR programs out there that you may want to look into once you have mastered Adobe’s. One that I prefer is Photomatix. This is a sweet program and not only as versatile as Adobe’s, but offers many others features that are helpful and even includes a separate plug-in for Photoshop. You can find them at http://www.hdrsoft.com/
It costs around $120 for the bundle which included Photomatix Pro and also the Photoshop Plug-in.
Well that’s all for today, hope you have fun and don’t forget Bracket, Bracket, Bracket!