Well, not exactly but perhaps a mini HDR; but a very useful one at that. There are numerous articles, Web tutorials, books written about the high dynamic range image processing and for a good reason. The process yields remarkable results with detailed highlights and detailed shadows. Images obtained from HDR processing encompass a range of tonalities that would not be possible to capture on film or in digital sensors. After all, who does not want to have a film or a digital sensor that doubles or triples the EV range, maybe even more. I have used this technique with excellent results, the image on the right is one example and it is also a 7-photograph stitched panorama (click to enlarge). But, I want to talk about using the same tool I use to process my HDR images, Photomatix, for a different purpose that does not require advanced planning. This use that I will present here has been generally ignored in most of the articles, perhaps because it is not “real HDR” but who cares. It produces really good results for difficult images. My intention is not to present a full tutorial on how to use Photomatix for HDR, I will present you with the initial screen with the default settings, then show you the completed version with groups of settings following that. If you carefully review the  small gallery of images at the end you will get an idea how the process works. You can even get help from an article written by John Paul Caponigro in a recent issue of Digital Photo Pro magazine. He explains the HDR process using multiple images, but you will understand what various controls do.

Although Adobe Photoshop handles processing HDR images, even saving them in an HDR file in radiance format and tone mapping the image to a low dynamic range so that we can display and print it, the tools it provides are not as easily usable as the tool of my choice, Photomatix from HDR Soft. Typically, one would select 3-5 photographs exposed 2EV’s apart ranging from -4 to +4 in RAW format. Then Photomatix opens these RAW format files and processes them to generate one HDR file that cannot be directly displayed on a normal monitor because of the great range. This file can be saved in one of the available formats in 32-bit, which is not a bad idea at all. Then, using the second component built into Photomatix, one creates a tone mapped version that has a dynamic range that is suitable for displaying and printing, with or without further adjustments. Tone mapping is a required step until either we can all afford an HDR monitor, not very likely at $20K; or the price of that beast comes down. Essentially, without tone mapping this process is currently not of much use.

One of the capabilities of Photomatix is to create a pseudo HDR file from a single RAW image file. It does not do this by some form of trickery, but by converting the full range of RAW format to an HDR file. With today’s digital cameras with their 14-bit image capture, there is quite a bit of information that can be used if properly processed. It is a matter of choosing the portion of the dynamic range in processing and tone mapping that portion to the usable spectrum of luminosities. When we develop a RAW file in a program like Lightroom, or Photoshop Adobe Camera RAW we are doing exactly that. So, why bother using Photomatix for this purpose? The answer lies in first, being able to see the full dynamic range, albeit in small sections at a time in a small view port; second, the tone mapping in Photomatix works really well with problem images. Take a look at the following images (click to enlarge):

They are, the original RAW file, Lightroom processed, Photomatix processed. You may think that I purposely did a lousy job in Lightroom, but trust me, I tried to retain a similar dynamic range as I saw in the Photomatix processed image and some tonality in the sky. My attempts to add a more pleasing brightness to the whole image resulted in the sky being washed out, at least partially on the right side of the image. I know, I could have used the gradient fill available in Ligthroom 2, selectively brighten certain parts, etc. But I wanted to keep the adjustments to a set of global adjustments, affecting the entire image in both programs.

The process is quite straigth forward if you have Photomatix. If you don’t, you can download a trial version that is functional for 30 days I believe. So, here is how I do it in general and my settings for this image.

1. Start Photomatix, you will see its spartan interface. Don’t let that fool you, more powerful parts are a few menu clicks away
2. From the menu, follow ?File/Open” and point to the RAW file you wish to process

Photomatix will load the file and process it according to the parameters set in the settings. At the load time, there are no more selections, it’s simple. After it is done, it will present the pseudo-HDR file and the small HDR viewer. The second image in the small gallery below shows the screen capture at this stage. Note that the HDR viewer is displaying the area pointed by the arrow in the middle of the image. At this stage, if you like you can save your image as an HDR file in Radiance format. Photoshop can open this 32-bit image file if you like and you can process it in Photoshop. I prefer to tone map in Photomatix because the controls are more powerful and also much easier to use. Whether you save it at this point or not, click on the “Tone Map” button on the tool bar.

Tone mapping interface has quite a few controls. My intention is not to present a full tutorial on what these controls do, so I will present you with the initial screen with the default settings, then show you the completed version with groups of settings following that. If you carefully review the following small gallery of images you will get an idea how tone mapping works. You can even get help from an article written by John Paul Caponigro on a recent issue of Digital Photo Pro magazine. He explains the HDR process using multiple images, but you will understand what these controls do.

When you like what you see, click on the “Process” button to tone map the image and save it as a TIFF file. The bit depth and the color space are determined by the preferences. Clearly, this image is not finished to reflect my vision for it. But I will start in Photoshop with an image that will have full range of information in the shadows and the highlights as well as midtones. From there, I will take it to where I want this photograph to go.

Take a look at the gallery now, it will give you a general idea about what is possible in a non-standard RAW processing engine. So, next time you have a difficult image, consider giving Photomatix a try. It may actually save the day.

Images list: 1. Photomatix screen, 2. RAW image opened and processed, 3. Tone mapping with default settings, 4. Tone mapping as I applied it, 5. HDR settings, 6. Tone settings, 7. Color settings, 8. Smoothing settings

I face situations where I may want to accommodate a wide tonal range in an image that has too much contrast. I picked a sample image to use here showing two garages with white paint under direct sunlight with a heavy shadow area behind a fence. (Figure 1)

In this tutorial, I will use the combined RGB channel and not be concerned with color corrections. The purpose is to illustrate a technique on controlling the range. You may save and use the image above to follow the rest of the tutorial.

Simple curves adjustment

I made a decent effort to adjust the curves to open the highlights while retaining some detail on the white parts of the garage. Here is the result (Figure 2):

I have managed to adjust the whites and, to some extent, the mid-tones but the shadow area on this side of the fence is still too dark. Here, the split adjustments of the highlights and the shadows will give me a greater control on maintaining the tonal range that I would like.

The mask

First, I need to create a mask that consists of the luminosity of the image. To achieve that, click on the “Channels” tab, then Ctrl-click on the RGB combined channel. This will select the luminosity of the image. Press Ctrl-C to copy this selection. We now need a new channel, click on the fly out menu arrow on the top right corner of the channels panel and select “New channel” from the menu, accept the suggested name “Alpha 1.” You will see a blank channel. Make sure to click on this channel and press Ctrl-V to paste the image in the clipboard. Now we have a B&W image of the luminosity of the original. Press Ctrl-D to release the selection so that no part of the image is selected. Since I want the mast to control the shadows, I will invert the image before making the final adjustment to create the mask. To do this, press Ctrl-I (making sure that you have already pressed Ctrl-D.)

To make the mask work the way we want, we should enhance its contrast. Summon the “Curves” tool, press Ctrl-M and make the curve to look as follows. The important thing to remember is to create a smooth curve. Here’s my curve (Figure 3).

After this adjustment, my Alpha 1 channel looks like this (Figure 4):

Now I have a high contrast channel that I can use, I want to use it to select the appropriate parts of the original image. Press Ctrl-click on the Alpha 1 channel to select the mask, then click on the RGB channel. The mask has created the selection on the RGB channel which will control the areas that will be affected by subsequent adjustments.

Curves, part I

Now, click on the “Layers” palette and using the black-and-white circle at the bottom of the palette window, create a “Curves” layer. This adjustment layer will only affect the shadow areas of the image and to a lesser extent some of the mid-tones. I have adjusted my curves as follows. This retains the highlights the way they were, makes slight adjustments to the mid-tones, and significant adjustments to the shadows.

The resulting image after this stage looks like this:

I can see more in the shadows, even the reddish patio tiles and other detail are visible.

Curves, part II

Now I will turn my attention to the highlights which requires the exact opposite of the mask that I have created for the shadows. Using the mouse, Ctrl-click on the curves mask, which shows the high contrast B&W image on its thumbnail. (Alternately, you can switch to the channels palette, and Ctrl-Click on the Alpha 1 channel.) We want to mask the exact opposite of the selection, so press Ctrl-Shift-I to select the inverse. Again, using the B&W circle at the bottom of the Layers palette, create a new curves layer which will affect only the selected areas, highlights. Any adjustments we make on this curve will affect the highlights and to a lesser extent the mid-tones. Here is my curve for this adjustment (Figure 7).

Finished work

And the resulting adjusted image has the correct highlights and reasonably open shadows. Since we have both curves layers active, the image shows the combined adjustment and yields full tonal range.

If you think the same result can be obtained by using a single curves layer on the original image, you may be (may be) right. Try it and observe how fussy you have to be to make it look half way decent. Where this method of split level curve adjustments are quite tolerant of substantial adjustments on their respective curves.

I would like to hear from you, feel free to leave a comment or send an e-mail a message to me.