Changing the Color Depth of the Image

From the Color menu, select Color Resolution. The Bits per pixel box says 24. The larger the number of bits, the larger the number of colors that can be displayed.

Use the drop down menu to select 6 bits. Notice that the appearance of the image changes. The areas of color are no longer smooth. The third number in the status bar in the lower left corner has changed from 16M to 64, meaning that only 64 colors are displayed in an image with 6 bit color depth.

Substituting One Color for Another

On occasion, you may wish to substitute one or more colors in an image with others. Most photo editing tools allow you to substitute colors. SnagIT changes all occurrences of the color that it finds in your image to the new color.

Make sure your galaxy looks as it did when you first opened it. If you have applied some changes then from the Edit menu, select Restore to restore its appearance to the original.

From the Color menu, select Custom Color Substitution.

In the Original Color area at the top, click the Select button. The pointer changes to a dropper. Move the dropper into the image and click to select a color to replace.

In the Substitute Color area at the bottom, change the Red color number to 255, the Green to 0 and the Blue to 255. The color box shows the new color, magenta.

Click OK.

Notice that only a small dot changed to the new color, even though your image may have large areas that appear to be the color you selected. Remember that this image may contain up to 16 million colors, so colors that look the same may be slightly different.

To change colors that are similar and not just colors that are exactly the same, select Custom Color Substitution from the Colors menu.

Change the Color Accuracy from 100% to 50%. Click OK. Now a much larger area of color is changed to the new color.

Changing Brightness, Contrast, Hue, and Saturation

Among the most commonly used Color changes are Brightness and Contrast. Images taken with digital cameras often need these adjustments to look their best.

If the galaxy image is open, close it now by clicking Cancel output from the SnagIT File menu.

Press the SnagIT hot keys, Control, Shift and p again to open a new file. Open the file on your diskette called image1.jpg. Notice that image1.jpg is a 24 bit image, it contains as many as 16 million colors.

From the Colors menu, select Brightness. Move the slider left and right to decrease and increase the brightness of the image. When your image looks optimal, click OK.

From the Colors menu, select Contrast. Move the slider left and right to decrease and increase the contrast of the image. When your image looks optimal, click OK.

From the Colors menu, select Hue. Move the slider left and right to change the Hue. Hue is a combination of two colors changing from red to green to blue and back to red. When your image looks optimal, click OK.

From the Colors menu, select Saturation. Move the slider left and right to change the Saturation. Saturation determines the purity of the color combinations. When your image looks optimal, click OK.

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