Sumptuous HDR – How to Post-Process HDR Images

If you’re new to HDR processing or feel you might have some gaps in your knowledge you’ve come to the right place.  Below you’ll find a no-nonsense, step-by-step guide to merging and processing your HDR images for maximum effect.


As with most things in life, there are many different ways to go about this.  This is my process for post-processing images for HDR.  I don’t mean to imply that my way is right and other ways are somehow wrong; this is just how I do it.  I use Adobe Lightroom and Photomatix Pro for nearly every HDR image I produce.  Once in awhile I feel the need to dip into Photoshop-proper for some finishing moves.

Buy Adobe Lightroom | Buy Photomatix Pro

(use coupon code sumptuousart with Photomatix for a 15% discount)

Capturing the Dynamic Range

Before you can process the images you have to have them.  You would take 3 or more pictures at different exposures in order to capture the full dynamic range of the scene.  This is only necessary when the dynamic range of the scene is greater than your camera can manage – the difference between the brightest highlights and the darkest shadows is beyond your camera’s capabilities to maintain detail.  HDR processing is one of many photographic tools.  Like all tools, it is not appropriate in all situations.  I’ll circle back to when not to use HDR later.  For now, here are some articles on how to shoot bracketed series of exposures with the intent of merging them for one HDR image:

Shooting for HDR with the Nikon:  D40x | D7000 | D700 | D800

Now you have a bracketed series of exposures.  From here on we’re going to operate as though you have 7 exposures taken at 1 exposure value (EV) spacing.  That means that there is a full stop difference in exposure between each of your pictures.  You have a series of the following exposure values:

-3 EV | -2 EV | -1 EV | 0 (balanced exposure) | +1 EV | +2 EV | +3 EV

Perhaps you were using the D7000 or D7100 or another camera that allows a greater (than 1) EV spacing.  Perhaps you only have 3 exposures at -2 EV, 0 EV and +2 EV.  You should still be able to follow this guide.  Three exposures with 2 EV spacing between them should be good enough to capture the dynamic range, providing the files you need, to create great HDR images for about 90% of the scenes you’re likely to capture.

Importing and Organizing

I use Adobe Photoshop Lightroom to manage all of my images.  This isn’t meant to be a Lightroom (LR) tutorial, but I use it extensively and talk about it quite a bit.  If you haven’t decided if you want to commit to Lightroom yet, Scott Kelby put together a series of videos on 100 Ways Lightroom is Better than Adobe Bridge.

Launch Lightroom.  Connect a card reader and insert your camera’s memory card.  If you’re not already in the Library Module press G on your keyboard to get there.  Click the Import… button.  If it doesn’t happen automatically, select the drive your computer assigned to the memory card (mine says “NIKON D800”).  You’ll be presented with the Lightroom Import interface.

LR_Import

At this point you’ll need to make some decisions.  One of Lightroom’s features is that you can apply what they call “Presets”.  Lightroom Presets are all over the application, but if you look at the bottom center of the image above, you can see that I used an Import Preset called “Standard Import”.  This is an Import Preset that contains a Develop Preset called “Camera Calibration” which you can see in the upper, right-hand portion of the above screen-shot.  I set up and named those Presets myself; they don’t come with Lightroom.

For all the image files I import into Lightroom from my camera’s memory card I apply the following Develop Presets:

  • Basic – White Balance (WB) is set to Auto
  • Detail – Sharpening is set to 25
  • Lens Corrections – Profile is set to the Make of my camera (the Model and Profile will take care of themselves based on the Make).  Lightroom is able to figure out which lens I used based on the Make of my camera.
  • Camera Calibration – Set to “Camera Vivid”.  This is based on the options your camera manufacturer provides.  I use Nikons, so Camera Vivid is one of the options.  Users of other camera brands may see other options.

Please Note:  The good folks at HDRSoft (the company that produces Photomatix) contacted me to let me know that, in general, they recommend against using the Camera Vivid setting I mentioned above.  They said, ” You mentioned importing your images with a Vivid preset and then you are exporting those for HDR.  But for HDR, it’s best to keep most of the develop settings at ‘zero’.”

They also provided this link:  http://www.hdrsoft.com/support/faq_photomatix.html#process_raw for further review.  It’s part of a larger Frequently-asked-questions (FAQ) document regarding HDR processing that is quite useful.

As I mentioned earlier, this is a write-up of the process I follow when processing images for HDR.  In the interest of helping others produce the best artwork possible (in an honest way), I wanted to let you know what I do as well as what the professionals recommend.

End Note.

That’s it.  By the very fact of importing my picture files onto my computer, I’ve already done those things to the images.  It isn’t much (and some people do much more), but I don’t do a whole lot to the straight-out-of-camera exposures before merging them to one file as an HDR image.

Huge Free Lightroom Tip:  You might think that your image files were imported into the folder you specified.  You’re right, they were.  But that’s not what Lightroom displays to you immediately after importing.  Lightroom puts you in a Catalog called “Previous Import” whether you realize it or not.  This can cause confusion.  Take a second and glance over at the left side of Lightroom’s interface.  Scroll down to the Folders section and select the folder into which you just imported.  You may see the same image files you just saw before (in Catalog – Previous Import), but your confusion level will drop by 2 points.

We’ve imported our bracketed series of images into Lightroom.  We’ve done some very basic processing as part of the import process.  Before doing anything else, I always take the time to do a little organizing before moving on.  I group all of the newly-imported series into stacks.  Select the first image in each series, hold down the SHIFT key and click the last image.  With all images in the series selected, use the keyboard shortcut CTRL + G (Command + G on a Mac).  This groups the images into a stack in Lightroom.  You’ll need to expand the stack when you’re ready to merge the images.  We are now ready to merge our multiple exposures into one HDR image.

Or are we?

Selecting Images for HDR Merging

You’ve captured multiple exposures of the scene.  You’ve got the whole dynamic range.  Perhaps you even read RC Concepcion’s article on Shooting for the Basement.  Once you get your pictures into Lightroom that doesn’t necessarily mean you’re going to use all of them.  Look at each of the images (exposures) in your set.  Remember why we’re doing this in the first place – to get details in both the extreme highlights and the extreme shadows.  Does each exposure help us to that end?

You can check the histogram if you like.  Select the darkest exposure and look at the histogram.  Is it bunched up to the left?

darkThis one is bunched up to the left.  That means it’s under-exposed – do the highlights still have detail?

Now select your brightest exposure.  Is it bunched up to the right?

lightYes, pretty much.  We have a darkest exposure that the histogram says is very dark and a brightest exposure that the histogram says is fairly bright.  At this point I think we want all of the images.  But when might you not want to merge all the pictures you’ve taken?  You don’t want to merge all the exposures you’ve taken when the brightest highlight picture doesn’t show anything more than the second-brightest picture or the darkest-shadow picture doesn’t show anything more than the second-darkest shadow picture.  By “show” I mean this:  Are there details in those highlights or shadows?

You could make this decision using the histogram alone, but that would be like using math to define beauty.  You could also do this:  Look at the second-to-brightest image and then look at your brightest image.  Are you getting any more shadow details between the two?  If “Yes” then use both of them.  Now look at your second-to-darkest exposure and compare it to your absolute darkest one.  For the parts of the scene that are really bright, are you getting more detail in the darkest image?  If you are still getting details in the darkest image that you didn’t get in the second-to-darkest image, then keep all of them.

But seriously, ask yourself this:  Am I getting something of value out of every single exposure?   Am I getting as much detail in the shadows as possible?  Am I getting everything I can from the highlights?  Am I getting details from both ends of the dynamic range?

Merging Images in Photomatix Pro

If you haven’t already done so, expand the stack of images and select all of them.  Right-click somewhere within the stack and move your mouse over the menu option Export.  Once the next level of menus appears, click on Photomatix Pro.

First you’ll see a dialog with several options to specify before exporting:

PM_ExportThe options I choose are pretty much those above.  The only thing I really ever change is the Remove ghosts option (which I refer to as “de-ghosting” elsewhere in this tutorial).   Since we’ll usually be using a tripod when shooting our bracketed series of images, camera movement between exposures shouldn’t be a problem that often.  The de-ghosting option can be useful when parts of your subject are moving while you’re taking the shots.  Foliage could be swaying in the breeze, or people could be walking around.  The more you use Photomatix, the more you’ll get a sense of what the application can and cannot do when it comes to de-ghosting.  It can’t do everything.  If there are a lot of moving pieces (lots of people in a street scene for example), turning Remove ghosts on could actually make your image look worse.  Sometimes, like in the case of my Bourbon Street image, I like to purposely leave de-ghosting turned off to show some motion in the image.

Let’s talk about some of the other options.

Align images and Crop aligned result – You might as well align the images just in case the camera moved a little bit in between frames.  If you were on a sturdy tripod, chances are there wouldn’t have been movement, but I don’t think turning this on hurts anything.  Crop aligned result means that, if the images need to be shifted around to align them, the program can crop the image so the edges that are off the frame are cut off.  I don’t know why you would ever align the images and not crop the result.

Reduce noise – I never turn this on.  With Lightroom version 4 and later, you can clean up noise later, after the images are moved.  I would rather manually deal with noise myself than have Photomatix do it as part of the merging.  Also, Lightroom lets you selectively apply noise reduction to only parts of the image that need it so you don’t lose sharpness in more detailed areas of the image.

Reduce chromatic aberrations – Some people deal with chromatic aberration on each exposure before merging.  I don’t.  I always leave this option turned on for merging.  If chromatic aberration is still a problem with the merged image, Lightroom can help deal with it.

Show intermediary 32-bit HDR image – I’m not sure what use this option provides.  During the merging process Photomatix can show you a 32-bit version of the image that has a dynamic range that exceeds what your monitor can show.  What you’ll likely see is an image that looks almost completely white in some areas and almost completely black in others.  There may be faint traces of color in places.  Really, I’m not sure what purpose this is supposed to serve.

Automatically re-import into Lightroom library – Why wouldn’t you do this?  You might as well, and don’t forget to check the Stack with selected photo option at the bottom.  I like to keep all my originals and merged images together in stacks.

Output Format – This is the file that will come back from Photomatix.  It will be a TIFF.  You might as well use the greatest color depth you can with 16-bit.

These settings are sticky.  They will remain as you left them the next time you export to Photomatix.

Once you have the export settings the way you like, click Export.

Go make yourself a cup of coffee or something.  Depending on the file size of each of your images and how many frames you’re merging, this could take awhile.  With 7 30+ MB image files from the D800, my laptop chugs along.  My desktop supercomputer can do it in just a few seconds though.  You’ll see several progress dialogs pop up and go away.  Eventually Photomatix Pro will be up and running with your merged image.

Processing Your Merged Images in Photomatix Pro

Foremost on your mind should be this:  Merging your multiple images into a single HDR image is only the first step in processing for HDR.  It is not the last step and certainly not the only one.  You should not spend much time operating inside Photomatix.  For my most complicated images I would still never be in Photomatix for more than 2 minutes.  Usually this step takes only a matter of seconds.

The settings in Photomatix Pro are sticky.  Wherever you left them the last time you were here, that’s how they’ll be when you return.  This can be useful when processing several series from the same shoot in a row.  The settings from one set can be a good starting place for the next.  However, if you haven’t been in Photomatix in awhile, or you are processing a set from a new shoot, you may not want the settings from your last session to influence your current one.

The first thing you may want to do is to click the Default preset within the Presets options.

The Photomatix Pro (4.2.6 as of this writing) Main Window:

PM_Default

Please note that, at the top-left corner of the window are options for Process and Method.  I don’t recall the last time I used something other than Tone Mapping for the Process and Details Enhancer for the Method.

The Presets options are along the right side, and the Default option is at the top of the above screen shot.  Your view may look a little different.  Whether your image is in landscape (above) or portrait orientation will make the screen look a lot different.  You might as well maximize the window if it’s not already.  I do look at the histogram, so I make sure it is visible (bottom right in the above image).  Beyond selecting the Default option, I don’t use the Presets options, so I’m not super concerned if I can see these options.  The histogram and the Adjustments, those are the important things.

Quick and Dirty Merging

I’m not sure how “dirty” this is, but these settings will work for about 72% of the images you want to process.  If you’re in a hurry, try doing these things:  Move the Strength slider all the way to the right.  Bump up Color Saturation a couple notches.  Adjust Luminosity until your image doesn’t look too dark or too bright.   Move Detail Contrast up to, like, 6.0.  Move Black Point up one full notch (I can land on 0.009%).  Slide Temperature around until you like it.  Click Save and Re-import to get your merged image back into Lightroom and be done with it.  When I do these things, my image looks like this:

PM_quick

It’s not too bad, but that was quick and dirty.  Let’s explore all of the Adjustments sliders and how you might use them.

Merging Images in Photomatix Pro

If you scroll down to the bottom of the Adjustments pane, there is a little question mark (?) icon with an expanding triangle next to it.  Click the expanding triangle to expand a small box.  This is a context-aware help box.  When you hover your mouse over any of the Adjustments sliders this box will tell you what the slider does.  The Photomatix people seem to understand that their sliders aren’t particularly delicate, so they tell you what each one would do if you dragged it all the way to the right or left.

The adjustment sliders in Photomatix Pro are not particularly sensitive or delicate.  You can experiment for yourself, but I think you’ll find that dragging them a little bit to the left or right has almost no effect.  So, drag big or go home.

Have you ever had an eye exam?  Working in Photomatix is a lot like that.  You’ll drag a slider way to the right and ask yourself “Does it look better or worse.”  Then you’ll drag the slider to the left and wonder “Does it look better or worse?”  These are “Yes” or “No” questions.  I’ve found that there are few shades of grey when merging your photos for HDR.

Strength:  Drag the slider all the way to the right.  This is the first move I always do in Photomatix.  After adjusting the other sliders I might come back to this one and back it off a little, but, in general, I leave this one set at 100.

Next, I drop down to . . .

Detail Contrast:  Slide this one all the way to the right as well to see how it looks.  Unlike the Strength slider, I usually back this one off right away.  Every image is different, but I often end up with this one around 4.0.

At this point I look at the image for overall brightness.  If the image is too dark, I go to the Luminosity slider next.  Dragging this one to the right will brighten the overall image.  If only the mid-tones are too dark I use the Gamma slider instead.  Normally I use a combination of these two sliders to adjust the brightness of my image.

Black Point:  I like to have some areas of my image be pure black.  Most of the time I move this slider up to the first notch.  This puts the number at around 0.009%

Lighting Adjustments:  For some reason I am unable to not mess with this slider when I process an image.  If you check the Lighting Effects Mode checkbox the slider turns into 5 buttons, but the affects on the image are the same.  Here’s what I normally do:  Drag the slider toward the right and observe the results, drag it to the left and observe the results, and then put it back in the middle where it started.  I honestly can’t remember the last time I used Lighting Adjustments to make a change that I kept.  This is just a personal preference.

At this point you should have an image that has the exposure you want.  Here’s what mine looks like so far:

PM_expYou can see where I’ve left the sliders.

You could consider yourself done at this point.  Once you have the exposure the way to want it, everything else can be done in Lightroom or Photoshop.  However, there are still two sliders I usually adjust to check what difference they make.

Color Saturation:  Go easy with this one.  A little goes a long way.  If I want to bump up the color a bit, I’ll move this one to the right.

Temperature:  Again, this can easily be adjusted back in Lightroom, but sometimes I move this one around a little to either warm or cool the color temperature.

Except for the ones mentioned above, I almost never touch any of the other sliders.  Smooth Highlights and Shadows Smoothness are sometimes useful if you have large areas in your image that are kind of dark or bright and don’t have a lot of detail.  Perhaps a cloudless sky or dark corner could benefit from this adjustment.

This is what my final merged image looks like:

PM_finalWhen you’re ready, click Save and Re-import.  Depending on file size and your hardware, this will take a little bit of time.  Eventually you’ll be back in Lightroom.  Since we told Photomatix to stack the new, merged image with the others, it will appear there.  However, Lightroom always puts the new file in the second position.  I like to drag it to the top of the stack and then collapse it.

Processing the Merged HDR Image in Lightroom

Open the HDR image in the Develop module.  The first thing I like to do with the new image is apply Lens Corrections.  Access that panel and check Enable Profile Corrections.  If Make, Model and Profile don’t fill in automatically, select your camera and lens.  You may notice lens distortion go away immediately.

LR_LensCorr

Images coming back from Photomatix can look a little soft.  I usually bump sharpening up quite a bit.  Access the Detail panel and try moving the Sharpening Amount slider up to 50.  I’ll go up to 80 if I think the image looks better with that amount of sharpening.

Before Sharpening With Sharpening

If there are any large areas without detail, sharpening can increase the appearance of noise.  You can counteract this with the Masking slider.  If you hold the ALT key (Option key on a Mac) while you slide the Masking slider, Lightroom will show you where the masking is being applied.  You want to mask areas where you don’t want sharpening applied.  Remember – Black conceals, white reveals.

LR_MaskIn the above screen shot, the areas in black are “concealing” the sharpening adjustment.  You’ll want to see black only in areas with little or no detail.  While you’re on the Detail panel, you might as well see if you need some noise reduction.  With Lightroom 4 and later, the noise reduction functionality works pretty well.  You can get away with an increase of up to 25 before you start to lose detail.

For HDR images, I always start post-processing with Lens Corrections and Sharpening.  After that I go to the top of the Develop panels and continue processing the image as I would any other image.

Access the Basic panel.  The first thing I notice about my example image is that some of the highlights are blown in the windows along both sides.  We’ll come back to that in a minute.  First I want to get my color tone right by adjusting White Balance.  Under the heading “WB” I first slide the Temp slider in both directions to see which one I like better.  In this case I prefer a slightly warmer look.  The image is already a little warm, so I moved the Temp slider only up to +5.  For almost all images (HDR or otherwise), I usually adjust the Temp slider and rarely mess with the Tint slider.  In this case I looked at tint both greener and more magenta and didn’t like either one.  You can double-click the pointer for any slider to send it back to its default.

If you want to get your White Balance as close to reality as possible, click the eye dropper icon to select it.  You’ll see that your cursor is now an eye dropper.  Look for an area of your image that is neutral gray, or should be neutral gray.  Light shadows, clouds, clothing and other things can have the lighter shade of gray you’re looking for.  Click this area with the eye dropper icon on your cursor, and Lightroom will adjust White Balance based on that area that you just said should be neutral gray.  Sometimes this makes your White balance perfect; other times it can give you a good starting point, and you’ll adjust the sliders a little more yourself.  Sometimes you may need to select the eye dropper a few times and try different areas.  If you have the left pane open you can see a real-time preview of what your changes will look like based on the location of the cursor.

Look down into the next section of the Basic panel called Tone.

LR_ExpHist

This is where we’re going to adjust the exposure.  Before moving any of the sliders, hover your mouse over the pointer for each one (except for Contrast).  When you hover over the exposure sliders, the histogram above the panel highlights the area that will be affected.  The Exposure slider affects the mid-tones strongly.  Highlights and Shadows affect the brighter and darker parts of the image, and Whites and Blacks affect the brightest and darkest areas.

In the screen shot to the right you can see that hovering over the Highlights slider causes the histogram to highlight the area that will be affected when the slider is adjusted.

If you hold down the ALT key (Option key on a Mac) and click and hold an exposure slider, your image will change to a view of any clippings you might have.  A full discussion of shadow and highlight clipping and correction is beyond the scope of this tutorial for now.  If you already understand the concept, I’ll say that, depending on the image, I usually try to keep some areas of pure white and pure black, but not a lot of areas that are blown or lost completely.

Let’s talk about what it means to have blown highlights and lost shadows because this is the whole reason why we create HDR images in the first place.  We wanted to capture a scene where the difference between the brightest highlights and darkest shadows exceeded our camera’s capabilities.  That difference is what the dynamic range of a scene is – the difference between the brightest and darkest areas.  Not only might it exceed your camera’s capability to capture, but chances are it exceeds your monitor’s ability to display and your printer’s (or any printer’s) ability to print.

The term High Dynamic Range is a little misleading.  We are not trying to increase the dynamic range of a scene.  Remember, the dynamic range is already greater than our monitor can show.  The HDR process actually decreases the dynamic range of the scene.  We make the darkest areas not quite as dark and the brightest areas not quite so bright.  The goal is to be able to see details in both the shadows and highlights.  When the shadows turn to pure black, no detail can be seen, and they are considered “lost.”  When highlights turn to pure white, no detail can be seen, and they are considered “blown.”  Although images usually look best when there are some areas of pure white and pure black, we want to minimize those areas so they don’t take up large swaths of the scene.  We don’t want big patches of our picture where there is no detail.

If my overall image is too bright or too dark, I’ll move the Exposure slider.  But that is rare.  Normally I want to focus on either the dark shadows and bright highlights.  In the example we’ve been using, there are some blown highlights in the windows on both sides of the image.  For blown highlights I find that moving the Highlights slider has a better effect that the Whites does.  For the particular image we’ve been looking at, I dropped the Whites as well.  I checked my Blacks clipping and lowered that too.  Here are my settings and what the image looks like so far (I’m zoomed to 100% on a piece of it):

LR_Exp

Now let’s talk about that Contrast slider.  Chances are, we expanded contrast as much as we could when we merged the exposures in Photomatix.  I always check the Exposure slider in Lightroom anyway.  I drag it to the right and see if the image looks better.  For this image, I thought it looked a little better, but remember that the Contrast slider in Lightroom pushes the highlights and shadows further away from each other.  Since we’re trying to decrease the dynamic range, this isn’t an adjustment you’ll often want to make.

Curious about auto-tone?  Click the Auto button next to the title Tone.  What happened to your image?  Once in a blue moon this will actually make your image look better, but normally it makes it look worse.  Hit CTRL (Command on a Mac) + Z to undo the auto-tone.  The bottom third of the Basic panel has the title Presence.  The three sliders down there each have a strong affect, so please slide with delicacy.

Here is what our example image looks like so far:

LR_SoFar

Now let’s talk about the sliders under the Presence heading.  The Saturation slider increases the color depth of the entire image.  It normally has the affect of making your image look cartoonish and very unrealistic, so I pretty much never touch the Saturation slider.  Once in awhile I will use it to de-saturate an image, but almost never to add saturation.  The Vibrance slider is similar to Saturation, but it doesn’t affect every color in the entire picture.  It increases the color depth of only the colors that are presently less saturated than others.  I usually move this one a little bit to the right to see what things look like.

The Clarity slider is similar to when we added sharpening, but it applies the change in a more heavy-handed way.  basically this slider increases edge contrast.  It finds all areas of the image where there are contrasting pixels and makes the contrast more intense.  If you drag it all the way to the right, you will get the harsh grunge look that is kind of popular.  I try to use it judiciously.  The Clarity slider can add noise back into the image, though, so you’ll want to zoom in on areas with little detail and check that.  You may want to drop back into the Detail panel and increase the noise reduction.  Clarity, Sharpening and Noise reduction all affect each other.  Normally your goal will be to get as much sharpness in your image with as little noise as possible.  Sometimes you have to make trade offs.

At this point, I am usually close to being done with processing.  I would have spent about 5 minutes total.  Every image is a little different, though, and may require special processing.  Here’s what we have so far:

LR_Presence2There are a few things that really jump out at me that need to be fixed.  We still have some blown highlights (and a little chromatic aberration) in the upper windows.  But the most egregious issue is the strong lens distortion caused by the extreme wide-angle lens I used.  Fortunately distortion is easy to fix within Lightroom.

Access the Lens Corrections panel and select the Manual tab.  If you’ve never used these sliders, it would be a good idea to slide each of them to the left and right to see what the affects are.  For my image, I want to correct the way the pillars look to be leaning away from the camera.  The Vertical slider will do this.  I ended up with a setting of -60.

At this point, I’m going to call this one done.  When you’re ready to share an image with the world, you first need to export it from Lightroom into an image file format.  For the most part, I export in one of two ways for one of two reasons:  To be viewed only on computer monitors and to be printed.  For viewing on monitors, I export a JPEG in the sRGB color space with a long edge of 20 inches, resolution at 72 and quality set at 80.

Low-Resolution Export Settings High-Resolution Export Settings

For high-resolution files meant for printing, I export JPEGs with quality set to 100, resolution at 240.  Every print lab I’m aware of requires the color space to be sRGB, so I never export using anything else, like Pro PhotoRGB.

Here’s my final image:

Finishing Moves

As mentioned previously, every image is different and may require special handling.

Spot Removal

There may be unsightly or distracting elements within your image.  Perhaps there was dust on the lens, spots on the sensor or just distracting objects within the frame.  The Spot Removal tool in Lightroom works fine for well-defined spots located in areas fairly free of details.  Adobe greatly upgraded the Spot Removal functionality with version 5 of Lightroom, but it still can’t do everything.  For things more complicated than spots, elements located in detailed areas or large pieces that need to be removed, Photoshop-proper is the best tool to use.  Depending on the situation, you would use a combination of the Spot-Healing Brush, the Clone-Stamp Tool or Content-Aware Fill.

Advanced Ghost Removal

You may have turned the de-ghosting option on in Photomatix when merging the original images.  Sometimes this works like magic, sometimes it doesn’t work that well and sometimes it can actually make an image look worse than it would have without using the tool.

Reasons why the de-ghosting algorithm of any particular HDR application doesn’t work can be varied.  You can probably count on having a problem when large areas of the image are in motion while you’re taking multiple exposures.  Perhaps a field of grass is blowing in the wind, or lots of people are walking around in a street scene.  If you can’t remove or crop out the elements that are in motion because they take up too much of the scene, you’ll have to mask them out using Photoshop.  The idea is that you’d take your HDR image (with the ghosting problems) and one of your original exposures (where, hopefully, the motion is frozen) and blend the two together.

You probably want to select your middle (balanced) exposure or one that is either 1 stop brighter or darker.  You’ll have to process it a little bit in Lightroom to get it to look similar to the HDR image.  So crank up the clarity, sharpness, vibrance and perhaps contrast.  You don’t need to get the whole image looking perfect, just the areas you’re going to blend into the HDR version.  Make sure the white balance of the two images is as similar as possible.  If you’ve done any cropping, straightening or distortion adjustment to the HDR image, you’ll need to do the same things to the single exposure.  Select the HDR image and the single exposure you made to look like the HDR image, right-click them and choose the menu option Edit In – Open as Layers in Photoshop.  Perhaps this goes without saying, but you need to have Photoshop installed on your machine.

Once the two images are open in Photoshop, make sure the single exposure is the top layer and the HDR one is on the bottom.  Make sure the top layer is selected.  At this point your Photoshop image will just be the single exposure since it is completely blocking the HDR version.  At the bottom of the Layers panel, look for an icon that is a white rectangle with a black circle in the middle.  If you hover over it, it says “Add a mask.”  Hold down the ALT key (Option key on a Mac) and click the Add a mask button.  By holding down the ALT (or Option) key, the mask that will be added is completely black.  Remember: Black conceals, white reveals.  We’ve added an all-black mask so the single exposure is now completely hidden; the Photoshop image is now your HDR image.

Look at the bottom of the tool bar on the left side of the interface and notice the two color squares.  If the top one (toward the left side) isn’t already white, you need to make it white.  Press the D key on your keyboard to reset the black and white defaults and then press the X key to make white the active color.  Press the B key to select the brush tool.  Make sure it is the Brush tool that is selected (looks like a paint brush) and not one of the other “B” tools like the Pencil or Mixer Brush Tool.  In the top left corner of the interface there is a drop-down menu where you specify the size and hardness of the brush.  You’ll probably want a small-ish brush with medium hardness.  Back in your image, place the brush over an area where you want to fix something that is in motion.  You can fine-tune the size of the brush with the bracket keys:  “[” makes the brush smaller; “]” makes it larger.

Make sure the layer mask is selected and not the image.  A dashed white box will be around the layer mask.  If the box is around the image, click on the mask icon.  Paint over the area of the part you want to fix.  By painting with white on a black layer mask, you’re revealing what it was hiding.  The goal is to reveal a non-moving element that is on top of a moving element.

When Not to Use HDR Processing

We’ve talked about this a lot already, but I’m going to say it again.  The reason we even think about creating an HDR image is because the dynamic range of the scene (the difference between the brightest highlights and darkest shadows) is greater than our camera’s ability to capture.  If the dynamic range is beyond our camera’s capabilities, the next question we need to ask is:  Do we care?  Do we want to get details in those extreme highlights AND the shadows?  We could let the highlights blow out and expose for the shadows only.  We could let the shadows go to black and capture them in silhouette.  Either way, the image might still be a good one.

Most modern digital cameras have a pretty decent dynamic range to begin with.  You can probably capture around 10 stops of light with a single exposure.  Is the dynamic range of the scene really greater than that?  Well, of course, sometimes it is.  However, when we shoot in RAW (as opposed to JPEG), there’s still a lot of image data captured that Lightroom can recover.  Perhaps the scene won’t stand still for us.  Maybe we’re out there without a tripod.  If your camera has Highlight Warnings, turn them on.  After capturing the image with a single exposure, see if a significant portion of the highlights are blown.  Based on the view on your rear LCD display you can probably get a good idea if too much of the image is lost in shadows.  This doesn’t mean you didn’t get a good image.  When you have a RAW file back in Lightroom, brighten the shadows and darken the highlights in the Basic panel.  You might be surprised at what you can recover.

Please try to avoid making HDR images just for the sake of doing so.  This concept took me a little while to accept.  For a period of time I figured that HDR made every image look better and more interesting.  This simply isn’t the case.  By itself, your camera can often capture a great image with just one exposure.  If it doesn’t, Lightroom can help you out.  Let’s consider an example.

This is an HDR image made from 7 exposures that were captured at 1 EV spacing:

HDRFor a long time I was pretty happy with the above image.  However, I remember at the time I captured the exposures, I was thinking that this scene might not need the HDR treatment.  Granted, the place was dimly lit, but I had my tripod and nothing was moving.  About a year later my curiosity got the better of me.  I decided to take the 0 EV exposure (the image that my camera considered to be a balanced one).  Here is the 0 EV image straight out of the camera:

SOOCAfter some adjustments in Lightroom, this is what I was able to get:

Non_HDRPersonally I think this last image looks pretty good.  Compare it to the first one in this series.  Does the single exposure really look that much different than the HDR one?  I don’t think it does.  To me, this would be an example of when HDR was not necessary.

How to Create Bad HDR

Producing bad HDR is easy.  The ease with which we can create HDR imagery that is horribly offensive to the eye is probably the main reason why some people still think that HDR, in and of itself, is somehow wrong.  It’s just so easy to make it wrong.  The way to produce bad HDR art is to overdo it.  By “it” I mean “everything”.

An image file that comes back from a program like Photomatix contains more information than any of the single exposures that went into it.  When first we begin to post-process the merged image we might see that our adjustments seem to have more power than they did before.  We might get curious about what would happen if we moved Clarity, Contrast or Vibrance just a little further out.  To our surprise the image holds details and appears to only get sharper.  We start seeing colors we didn’t know existed.  We see detail we didn’t know was there.  We forget about recreating the original scene and cross the line into being . . . Artistic.

It’s a matter of temptation, really.  Just because you can do something doesn’t mean that you should.  So take it easy during post processing.  Temperance is a virtue.  It’s okay to create fantastical, totally artistic images, but remember that sometimes a color doesn’t exist in nature for a reason.

For Those Who Say that HDR is Bad for Photography

HDR processing is one photographic tool.  Like any tool it can be misused to ill effect.  Saying that HDR is, ipso facto, bad for photography is like saying that polarizing filters are bad for photography.  Polarizers can make our images look better when used properly in appropriate situations.

HDR processing can make our images look better when used properly in appropriate situations.

I suppose the difference with the HDR tool for photography is that we can go from plain to visually offensive in an instant.  It’s true that an overdone HDR image can make us temporarily envious of the blind (whereas improper use of a neutral density filter probably would not), but it doesn’t need to be so.  I believe it was Spider Man’s Uncle Ben whom Stan Lee once had say, “With great power comes great responsibility.”  If properly captured, your multiple exposures can be merged into a great image.  What you do with that great image is your great responsibility.


 

Share on Google+Share on FacebookPin on PinterestTweet about this on TwitterShare on RedditShare on TumblrEmail this to someone

3 Responses to Sumptuous HDR – How to Post-Process HDR Images

  1. Pingback: First HDR's with the Sony NEX-7

  2. Pingback: Sumptuous HDR - My Software Tutorial Is Finally Here - Sumptuous Art

  3. Pingback: D7000 – HDR GUIDE ‹ Daniel Carmichael Photography

Leave a Reply