Open the photo Courtney.jpg. This is one those pictures you can find at the “celebrity” sites on the Internet. Somebody with a 10 dollar scanner and a magazine declares his love for Courtney Cox and posts it to the web. It’s pretty bad. In fact, it’s so bad I want to delete it from my hard drive before it has a chance to contaminate my tiffs and pings. (Old digital joke: A picture is worth a thousand words. Unless it’s a jpg, then it’s only good for 500.) But suppose you truly are a Courtney fan, or maybe this is the latest picture of your only daughter, and you really want to look at something better than this. You can fix it, but let’s find out how it got so messed up in the first place.

Separating the channels
The next step is a bit of a pain, but it’s the only way in PI and is most instructive if you’ve never seen how the RGB image is put together. Use Format>Calculation (or Alt+M, then U, for the keyboard freaks) to open the Calculation dialog. Leave the Mask box unchecked. At the Channel drop-down menu, choose Red and click OK. This is a representation of Red/Cyan (remember those combos!) information in the picture. If you think of this as a “mask,” it’s easier to understand how it works. Areas of white let Red info through, darker areas will not and represent Cyan. Open Calculation again. Make sure the Courtney.jpg is chosen in both the Foreground and Background menus, then from the Foreground Channel drop-down choose Green and OK. Repeat the process, but this time choose the Blue channel instead of Green. You now have four pictures open, so close the original Courtney. We’ll be using it later, so don’t discard it.

Choose Window >Tile Vertically (Shft+F4) to get a good look. It’s fairly easy to see that the Blue channel, Untitled-3 (or the highest numbered window, if you’ve been doing other work) is the corrupt culprit here. The poor image quality around her arms and facial area is allowing too much yellow into the picture. In combination with the slightly too bright Red channel (which actually would have been OK with a decent Blue channel), Courtney has a yellow-orange-red glow that is very common to bad scans. Take particular note of the Green Channel. If one could be happy with a black and white picture, well, a couple of adjustments and there you are. Close all windows without saving, before you get the Blue flu.

I said you could fix this picture, and I wasn’t lying. But I haven’t given you all the necessary tools yet. I just wanted to show you how good girls can make bad pictures. Garbage in, garbage out.

Sometimes it’s necessary to use a few tools to make a picture look worse before you can make it look better. If that seems odd, consider that if you change the image, you of course change the channel information. And we can often use that new channel info to our advantage (especially so when we start with composites). More advanced users of PI can probably skip the next section, and go to the last exercise.

Hue and Saturation Tools
For those of you who aren’t aware of the Colorize and Range features of the Hue and Saturation dialog, these nifty little buttons create some intriguing possibilities. Open the Gradient jpg. First make about a 3 inch square selection with the Standard Selection Tool, then use Format>Hue and Saturation (Ctrl+E).

Notice the three radio buttons under Method near the bottom of the box. Click on Colorize and click the Preview box. If you move the Hue slider over to -50, you’ll notice that your selection is now various shades of green, no matter what the underlying colors are. If you move the slider all way to the right to 180, you have shades of red.

Play around with the Saturation and Lightness sliders. The important thing to notice is that the underlying luminosity remains the same, unless you add to much Lightness. Hit the Cancel button and remove the Selection.

For a demonstration, open the Portrait Man Dup (don’t close the gradient yet). Select the Magic Wand tool and make sure the + mode is clicked, and also Select by Area. Set the Similarity to 50. Check the Search connected pixels box. Click on the sky and most of it should be selected. It’s not that important. Open the Fill dialog (Ctrl+F) and set the RGB colors to R:128, G:128, B:128. This is 50% gray or Hex 808080 for you websters. Click OK. This is necessary because, try as you may, you can’t change the hue of white. Select the Airbrush tool and load it with white paint, then paint a few wispy clouds, or whatever pleases you, onto the sky. Then open the Hue & Sat dialog. Click colorize, check the Preview box, and play around with the sliders till you find a sky color you like. I used 37,45,55. When you click OK, you’ll notice your selection disappears. And if you check your Layers Manager, you’ll see you now have a sky object, as well. Remember my previous warning.

You could, of course, have just painted your sky into the selection. But Colorize is a useful technique for some grayscale manipulation we’ll be using later in compositing. In my example below I was in a playful mood and also changed his shirt, which you can do using a selection in the regular Master mode.

Go to Part 3