Before making color and tonal adjustments

The powerful tools in Photoshop and ImageReady can enhance, repair, and correct the color and tonality (lightness, darkness, and contrast) in an image. Here are some items to consider before making color and tonal adjustments.

• Work with a monitor that's calibrated and profiled. For critical image editing, this is absolutely essential. Otherwise, the image you see on your monitor will look different when printed. For more information on keeping color consistent throughout your workflow, see An introduction to color management.
• Whenever you make a color or tonal adjustment to an image, some image information is discarded. It's best to be judicious regarding the amount of correction you apply to an image.
• (Photoshop) For critical work and maximum preservation of image data, it's best if the image you work with is 16 bits per channel (16-bit image) rather than 8 bits per channel (8-bit image). As you make tonal and color adjustments and image data is discarded, the loss of image information is more critical in an 8-bit image than a 16-bit image. Photoshop CS has improved support for 16-bit images. Generally, 16-bit images have a larger file size than 8-bit images.

Note: If you jump back and forth between Photoshop and ImageReady, be aware that ImageReady converts 16-bit images to 8-bit for editing. Once the files are saved in ImageReady, they are permanently converted to 8-bit, and the discarded data is unrecoverable. However, if you are editing a 16-bit image in ImageReady and haven't saved it yet, you can return to Photoshop and the image will open as 16-bit without data loss.

• Duplicate or make a copy of the image file. Working on a copy of your image preserves the original in the event you need to use the image in its original state. (See Duplicating images.)
• Remove any flaws such as dust spots, blemishes, and scratches from the image before making color and tonal adjustments. For more information on retouching an image, see Retouching and repairing images.
• (Photoshop) Plan to use adjustment layers to adjust the tonal range and color balance of your image rather than applying an adjustment directly to the image layer itself. Adjustment layers let you go back and make successive tonal adjustments without discarding data from the image layer. Keep in mind that using adjustment layers adds to the file size of the image and demands more RAM from your computer. For more information on using adjustment layers, see Using adjustment layers and fill layers (Photoshop).
• (Photoshop) Open the Info or Histogram palette in Expanded view. As you evaluate and correct the image, both palettes display invaluable feedback on your adjustments. For more information on using the Info palette, see Viewing the color values of pixels (Photoshop) and for more information on the Histogram palette, see About the Histogram palette.
• You can make a selection or use a mask to confine your color and tonal adjustments to part of an image. Another method to selectively apply color and tonal adjustments is to set up your document with image components on different layers. Color and tonal adjustments are applied to only one layer at a time and will affect only the image components on the targeted layer.