Lighting Without Lights: Creating HDR Images in Photoshop
By Kevin Ames
Dateline: February 18, 2008
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
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.
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
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.
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.
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.