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I checked into a charming little hotel while on assignment
in San Diego recently. When I opened the door, the soft, diffused
light streaming into the room through the windows was
beautiful. There were flowers on the table in the alcove. I had to
have a photograph of it. There was one tiny problem. No lights.
I could see detail in the curtains
When I looked at the side of the bed closest to me, there was detail there, too.
The problem is contrast. While my brain put the
highlight and shadow details into one image automatically, what I
saw was beyond the ability of the camera to record it. Or was it?
No Lights. No Way?
Without lights to fill the shadows, the very bright outside light overpowers the
room’s interior. An exposure that captures detail in the curtains makes everything
else seriously underexposed. An exposure that reveals the foreground
blows out the windows, curtains, and most of the walls around them. Painting
the two together with layer masks is an option, though not a very good one.
The subtle shadows around the window and on the floor by the chair would be
way too dark. There is a better way. It’s called Merge to HDR. HDR means High
Dynamic Range. It is Photoshop CS3’s continued foray into the amazing world of
32-bit photography.
The Rules of Shooting for HDR
Here are the rules that must be followed in order for the merge to work.
- Shoot a series of photographs in one-f/stop brackets over a sixstop
range.
- The camera must be on a sturdy tripod. Movement between exposures
will cause the merge to fail.
- The brackets must be made with the shutter. Changing the aperture
subtly changes the size of the files relative to each other. This
is a type of movement. Using the aperture for the bracket won’t
allow the merge to work.
- Shoot RAW.
- Set Camera Raw’s Workflow Options to 16-bit.
I set up the camera on a tripod and composed the scene. I made a series of six
photographs, increasing the exposure by one f/stop each time The aperture is
f/8.0. The ISO is 160. The shutter speeds for the six shots are 1/6, 1/10, 1/20, 1/45, 1/90,
and 1/180, as shown below.
Merging to HDR
Once the photography is finished, assembling a finished HDR file is straightforward
and mostly automated. The six photographs used in this project can be downloaded here. They are original RAW files and will take a while to download, since the ZIP archive is 170 MB in size. Please use them only for the purposes of learning this tutorial.
Step One
Select the six RAW files for the merge in Adobe Bridge CS3. (This also works
in CS2.) Click on the first one in the series, hold down the Shift key, and
click on the last one.
Step Two
Choose Merge to HDR from the Bridge menu bar: Tools > Photoshop > Merge
to HDR. Photoshop opens each file in turn and then presents
a dialog box. The Filmstrip on the left side shows the files that will build the HDR file. The checkboxes allow you to exclude one or more from the merge.
Uncheck one of the files and the dialog view refreshes to show how that change would affect the merge.
Step Three
The Set White Point Preview shows the brightness range you can see on the
monitor. Move it to the right to reveal the highlight detail.
Move it to the left to open up the shadows so that you can see the caster
that holds up the bed, even though it is in deep shadows and the only light
used was streaming in from the window. HDR files have so
much information in them that to see it all you would need a monitor with a
white nearly as bright as the sun.
This setting is a preview. Move the white point slider close to its original
position. Select 16-bit from the Bit Depth menu and click OK.
Converting the Merged File
Step Four
The HDR Conversion dialog opens. Choose Local Adaptation
and click the triangle to reveal the Toning Curve and Histogram.
The other choices do not allow the use of curves. The
preview looks yucky (yucky is the technical term for really,
really bad).
Click on the dot in the lower left corner of the curve (the #1
shown in the illustration below) and drag it to the right until it is almost
touching the shadow pixels. When you release the mouse button,
the preview picks up the shadows. Click on the dot in the
upper right corner (#2) and drag it to the left about two and a
half boxes to bring in the highlights. Finally, click on the line
about three boxes up from the bottom (#3) and press the down
arrow key four or five times to boost the contrast.
Step Five
Zoom in to a 100% view by pressing Command (PC: Ctrl) + Option (PC:
Alt) + 0. Close examination shows a halo effect in some areas—especially
around the backlit flowers (as shown at right, click to enlarge)—and jaggies along the lower edge
Move the Radius up to 18 pixels. Click the Threshold slider and drag it to the
right. Release the mouse to refresh the preview. Move Threshold to 1.45. The
halo disappears, as do the jaggies. Click OK and Photoshop
converts the High Dynamic Range file to an editable 16-bit PSD.
Finishing Touches
There is just one more thing. In the days of film, architectural photographs were
made using view cameras. The backs could be pivoted so the film was parallel
with the walls. This movement made the vertical lines parallel, too. Some of
the higher-end digital cameras rival, or even exceed, the resolution of the largeformat
view cameras. Most do not offer the movements. DSLRs don’t have them,
either. This is a job for Photoshop’s Lens Correction filter. Then adding a bit of
warmth to the scene will wrap up the post-production on this photograph.
Perspective Correction
Step One
Duplicate the Background layer by pressing Command (PC: Ctrl) + J. Rename
the layer Lens Correction.
Step Two
Open the Lens Correction dialog box (Filter > Distort > Lens Correction).
Adjust the grid’s Size to 50. Change its color to black by double-clicking on
the Color patch to open the Color Picker dialog, and entering R: 0, G: 0, and
B: 0. Click OK in the Color Picker. You can move the grid by clicking the
Move Grid tool (M) and dragging it until it is over the line you want to be
vertical.
Step Three
Click on the Vertical Perspective slider and drag it to the left until the window
displays +13. You want to make the vertical edges of the two walls parallel
to each other. By lining them up to the grid, you are assured that they
are. When everything is aligned and in perspective, click OK.
Step Four
Hide the Background layer. Press C to get
the Crop tool. Crop the photograph inside
the edges of the walls that show as transparent.
Crop out the side of the table on
the left. Click the Commit checkmark in
the Crop tool’s Options bar.
Warm Up
Step Five
The curtains are too blue and the room looks a little bit cold. That was not
what I remember feeling. Warm it up some using a Photo Filter layer from
the contextual menu you get by clicking on the New Adjustment Layer icon
at the bottom of the Layers palette. The default setting of a number 85
Warming Filter at a 25% Density with Preserve Luminosity checked is perfect. Click OK.
Wrap Up
Step Six
Finally, highlight Lens Correction. Choose the Healing Brush (J). Select Current
Layer from the Sample menu. Hold down Option (PC: Alt) and click to
the left of the sprinkler head that’s just in front of the valence. Brush over
the head to remove it.
That’s much better. Now the photograph has the feeling I remember
when I walked into the room that first time. The important lesson is that if
you can’t take lights with you, be sure you have your tripod and Adobe Photoshop
CS3.
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