Color


Color

Q1:

What's the easiest way to color balance two photographs that overlap by about 2 inches? The photographs are two files and need to look clean where they overlap.

A1:

There are probably lots of ways to do this, and the choice may depend on your end result (print versus Web). I would consider using the Info palette to measure similar areas (e.g., the "same" sky or a similar green), then use Curves (Command-M [PC: Control-M]) to adjust one layer to make the color values match the other layer. In general, I would not use Brightness/Contrast as it does not do as good of a job as Levels. Also, consider adding an adjustment layer above each image layer so you can make ongoing changes.

Q2:

How do I fix a yellowish (bluish, greenish) photograph? Is there a quick way to fix a photograph that looks too yellowish?

A2:

This problem is known as a "color cast" and can often be fixed with one click. Use either Curves or Levels (both found under Image>Adjustments) and use the gray (midtones) Eyedropper to click on an area of the image that should be neutral gray. That should remove the color cast. If you're having a hard time finding a neutral gray point, try this: Click on the Create a New Layer icon, ensure the new layer is above your image layer, fill it with 50% gray (Edit>Fill), and change the layer blend mode to Difference. From the Create New Adjustment Layer pop-up menu choose Threshold, and drag the slider to the far left until the image turns white. Slowly drag the slider to the right. The first areas that appear in black are the areas that should be neutral gray. Hold down Shift and click to add a color sampler (to mark the spot). Click Cancel to remove the Threshold layer and delete the gray layer by dragging it to the Trash icon in the Layers palette. Now use the gray (midtones) Eyedropper in Curves or Levels to click on the color sampler.

Q3:

How can I fix the background of my scan? I have scanned an image and the background area surrounding my image is supposed to be white. My background looks a little yellowish (grayish). Is there a simple way to make the background area white again?

A3:

One simple solution is to use the Levels command (Image>Adjustments>Levels). In the dialog, click on the Eyedropper with the white tip (highlights). Then move to your image and click once on your yellowish (grayish) background. All the pixels of that shade will shift to white. Click OK. (Or, if you don't like the results, use Option [PC: Alt] to change the Cancel button to Reset, and try clicking on a different place.) Note: Although this method works well, be careful! If the background color also appears in the "object" itself, that color will change too. This Levels Eyedropper method changes all similar colors throughout the entire image. You may need to put a selection around your yellowish background (try the Magic Wand tool [W]) and adjust the Levels on that selection.

Q4:

How can I change the color of an object in my image?

A4:

Although you could use the Replace Color command, I would suggest using an adjustment layer for more flexibility. Make a selection of the object you want to change and then choose Hue/Saturation from the Create New Adjustment Layer pop-up menu at the bottom of the Layers palette. Drag the Hue slider to alter the color (you can use the layer mask to adjust the affected area later if necessary).

Q5:

How do I use Replace Color with a black or white object?

A5:

It's very difficult to colorize something that is pure black or white because, in effect, there's no color to replace. Chances are, however, that white areas are really various shades of a light color, so you may be able to replace those shades with another light color. It's very unlikely that you'll be able to replace a pale color with a vibrant, dark color. In the Replace Color dialog (Image>Adjustments), try starting by moving the Lightness slider to the left to darken the color, then experiment with the Hue and Saturation sliders (for a very dark color, try lightening first).

Q6:

How do I create a sepia tone look?


A6:

For the most flexible level of control, go to the Create New Adjustment Layer pop-up menu at the bottom of the Layers palette and add a Hue/Saturation adjustment layer. In the resulting dialog, turn on the Colorize checkbox and drag the Hue slider to choose the color you want. You may also want to adjust the Saturation and Lightness sliders, too. This way, if you later want to adjust the color, just double-click on the adjustment layer thumbnail and make the change in the dialog.



Photoshop CS2 Help Desk Book
The Photoshop CS2 Help Desk Book
ISBN: 0321337042
EAN: 2147483647
Year: 2006
Pages: 225
Authors: Dave Cross

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