Indexed color.
This mode reduces the color gamut of images to a maximum of 256 colors, thereby reducing the file size. By changing an image from RGB mode to indexed color mode, the program reduces the tones present in it, so the image loses quality if it has a lot of chromatic richness.
Summary
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- 1 Features
- 2 Using the indexed color mode
- 3 Formats
- 4 Convert to indexed color
- 5 Source
characteristics
The Color indexed using only one color channel (8 bits), while RGB uses 3 ( red , green and blue ) and CMYK 4 ( cyan , magenta , yellow and black ), which greatly reduces the possibilities of editing images in this mode.
When converting to indexed color, Adobe Photoshop creates a query color table (CLUT) that stores and generates the index of the image colors. If a color in the original image does not appear in the table, the program selects the closest match or uses dithering to simulate the color using the available colors.
Using indexed color mode
It is the proper mode of the GIF format , a type of image file destined for the internet . Its small size on disk, as well as its possibility of animation and transparency support make it ideal for the web . In images with gradients or many colors this does not have much quality, since GIF and indexed mode) does not offer it.
Although the color palette is limited, Indexed Color mode can reduce file size while maintaining the visual quality necessary for multimedia presentations and similar uses.
Formats
Color indexed files can be saved in the following formats: Photoshop, BMP , DICOM , GIF , Photoshop EPS , Large Document Format (PSB ), PCX , Photoshop PDF , Photoshop RAW , Photoshop 2.0, PICT , PNG , Targa or TIFF .
Convert to indexed color
To convert an image to indexed color, you must start with an 8- bit image per channel and grayscale or RGB .
To convert an RGB or grayscale image to indexed color:
1.Select Image> Mode> Indexed Color. All visible layers will dock; any hidden layers will be discarded. In grayscale images the conversion is done automatically. For RGB images, the Indexed Color dialog box will appear.
2.Select View in the Indexed Color dialog box to display a preview of the changes.
3.Specify conversion options
