PI6 Editing a Too-Dark Photo
o many of us have digital cameras and scanners now that photo editing is really coming into its own. Feedback on my Photos From Hell section tells me that many of you want help salvaging photos that turn out too dark. This tutorial shows how to correct a too-dark image by using a Tone Map. It works exactly the same way in PI5 and PI4.2, too.
Before I get started, a little disclaimer. The tone map values I've used in this tutorial apply to this particular photo shown below. Your too-dark photo may need different values, but if you follow along using my photo for practice, you can learn a few things about how to tweak midtones, highlights and shadows so that you can edit your own photos more successfully.
I love having a water lily pond in my backyard and like Monet, I never get tired of documenting them. I took this digital photo (shown below at 25% actual size) in bright, Florida morning sun and the exposure was wrong. The whole thing is way too dark, but I loved the little bug on the petal and thought this was worth some work to fix it up.
Part of the challenge of editing a photo is to take a cold hard look at your photo and figure out what's wrong. Sure it's too dark, but what does it need to improve it? Are you trying for a realistic look, or do you want something more dramatic with more contrast? In this case, I'm going for realism. The very light colors (flower) and the very dark colors (water) show up fairly well, but it's too murky looking and the green lily pads that I know should be there aren't showing up at all. This tells me that the colors in the middle, the greens and lighter yellows in the center of the flower, are not showing up. It is these midtones that very often need correction in underexposed or overexposed photos.
Although it seems hopeless, this photo can be readily improved by choosing Format, Tone Map. When the Tone Map dialog box opens, there are two tabs: Map and Highlight Midtone Shadow. The latter is selected by default.
Both tabs offer the same basic tools, which can be applied to the Master channel or to Red, Green and Blue channel (a bit more advanced than I'll cover here). However, the Map tab offers a series of preset Enhancements (arrow) that can be applied singly or Accumulatively.
For minor adjustments, the preset Enhancements may be all you need. Initially, I tried the Lighten Midtone and the Shadow & Highlight presets, but they weren't powerful enough for this particular picture. So instead, I edited the photo from the Highlight Midtone Shadow tab, where you must determine your own values for each attribute.
The first thing to do is to Lighten up the Midtones. Accordingly, you have to select a positive number for the Midtone value. Anything over 0 will lighten the midtones (negative values darken midtones). Getting the right value can take some experimentation, and there is a great deal of subjectivity in picking what looks right to you. Originally I used a value of 50. However, this "bleached" the image out too much and darker tones (detail and shadows in the flower) were lost. As a kind of tradeoff between preserving the darks and adding lights, I ended up selecting a Midtone value of 35. You can see what I mean by comparing the original image with comparisons of the two Midtone levels, shown below.
To continue brightening the image up a little, I chose a Highlight value of 10. It's just high enough to bring out the white petals without losing the shadows and other detail in the flower. To offset this lightening from Highlight, I chose a very small Shadow value of 5. Note that I didn't change the Histogram scale factor and that these changes were applied to the Master channel.
Now for one last enhancement to strengthen the contrast and sharpen the image up a little. Hit Ctrl+B (or choose Format, Brightness and Contrast) to access the Brighten and Contrast dialog box. Leave the default values and click the thumbnail just to the right (arrow) of the center, selected thumbnail. Click OK to close the box.
To restore some detail to the little bug on the flower, zoom in on the image. Select the Burn Retouch tool. In the Attributes toolbar, select Thin Burn from the Preset dropdown list. Scrub lightly over it to darken the bug, so he shows up better.
And here's the photo after editing. Now you can see all of the colors and details that didn't show up in the original photo.
Remember that every photo is different, but you should get some ideas from this tutorial that will help you get started on correcting your own too-dark photos.
This tutorial uploaded 1/19/01
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