Thursday, October 25, 2012

Making HDR using a single photo

After (straight HDR not tone-mappped yet)
     HDR or High Dynamic Range imaging is a process of taking multiple photos of a single scene in
different exposure ranges and combining them in post to show all the exposure ranges not usually
captured in normal photos. Usually at least three exposures, the highs, the correctly exposed then one with
the lows. The highs will enhance the bright areas of the photo. The lows will be enhancing the shadows.

    HDR photography has created quite a stir in photography world for a few years since it became popular.
Some photographers says its cheating, while on the other side of the fence they say it's just the same as what photographers do on post production. And there are also taking of sides on the pro HDR regarding the overdone HDR's.

    Enough about that now let's get started. I'm going to use Gimp as my photo editor and Picturenaut
as my HDR software for the reason they're both free and can both be good alternatives of their very expensive competitors.

    I assume you already have softwares to do this if not go ahead and download the two softwares.
Then choose a photo. Now, there are photos that are right for HDR and there are some that are not so.
A good photo for this are those photos with nice textures or contrast. A good example is a landscape photo with a rocky foreground and a nice cloud formation at the back. Go ahead and look for photos with those qualities and lets get started.

     First open Gimp. Then go ahead on open your photo by ticking "File" the "Open" the choose the photo you wanted to use for this project. Then go ahead and tick the "Color" tab then choose "curves.

Then the "curves" box will come up. You should see that box with a diagonal line on a grid. Go ahead and click and hold at the very center of the diagonal line.

Then drag it upward going slight left. Or you can experiment just make sure not to over expose the highlights.
This will brighten your photo thus giving details to your shadows.

When you adjusted to your liking then go ahead and click OK, then Save it or Export in Gimp. Then Go hit "ctrlZ" or "Edit" then "Undo". Then open another curves like what we did before only this time we will drag it downwards and slightly to the right.

This will darken your photo giving more details to your highs. If your happy with what you see then go ahead and save it.

Now Open your HDR software. In this case Picturenaut. The tick File the Generate HDR. Then click add then choose the three pictures. The original and the other two we edited with curves in Gimp.

Then we have to change the EV's or exposure values of the two that we edited. Go ahead and change the one with highs or the bright one make it +2 or try out other exposures. EV's from +1 to +4 are the usual values depending on the photo. If you edited it bright enough just enough then a value of +2 will be safe.
Then on the one that we made darker make to -2 or again experiment on it.

You can check the exposure correction, ghost removal and color balancing to help you automatically correct those things. On the Weighting again you can experiment until you satisfied with the resulting image, so as the curve. Just experiment on the settings there and see how and what are it's effects on the picture. this will help you a lot because each photo will be done differently there not one definite setting for every picture you have to experiment on it. Now you have an HDR photo.

Now there are more things you can do to it. Or you can save it straight because the generated image is already good as is. Or you can go further and do some more refining. The common thing done is tone mapping which as far as I know part of the HDR process although a totally separate process. For Picturnaut the Tone map feature is under the "Picture" tab. Go ahead and try out some presets there or change things there to your liking then save it. One thing to remember about an HDR image is it still has to look real, don't over do it. Congratulations you just made an HDR from a single photo.

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