Adobe photoshop cs2 Manuel D’Utilisation
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ADOBE PHOTOSHOP CS2
User Guide
4
Choose a target mode from the Mode pop-up menu.
5
Click OK. The conditional mode change appears as a new step in the Actions palette.
See also
To convert a color photo to black-and-white
1
Open the photo you want to convert to black-and-white.
2
Choose Image > Mode > Grayscale.
3
If asked to discard color info, click OK. Photoshop converts the colors in the image to black, white, and shades of
gray.
See also
Converting images to Bitmap mode
Converting an image to Bitmap mode reduces the image to two colors, greatly simplifying the color information in
the image and reducing its file size.
the image and reducing its file size.
When converting a color image to Bitmap mode, first convert it to Grayscale mode. This removes the hue and
saturation information from the pixels and leaves just the brightness values. However, because only a few editing
options are available for Bitmap mode images, it’s usually best to edit the image in Grayscale mode and then convert
it to Bitmap mode.
saturation information from the pixels and leaves just the brightness values. However, because only a few editing
options are available for Bitmap mode images, it’s usually best to edit the image in Grayscale mode and then convert
it to Bitmap mode.
Note: Images in Bitmap mode are 1 bit per channel. You must convert a 16- or 32-bits-per-channel image to 8-bit
Grayscale mode before converting it to Bitmap mode.
Grayscale mode before converting it to Bitmap mode.
To convert an image to Bitmap mode
1
Do one of the following:
•
If the image is in color, choose Image > Mode > Grayscale. Then choose Image > Mode > Bitmap.
•
If the image is grayscale, choose Image > Mode > Bitmap.
2
For Output, enter a value for the output resolution of the Bitmap mode image, and choose a unit of measurement.
By default, the current image resolution appears as both the input and the output resolutions.
3
Choose one of the following bitmap conversion methods from the Use pop-up menu:
50% Threshold
Converts pixels with gray values above the middle gray level (128) to white and pixels with gray
values below that level to black. The result is a very high-contrast, black-and-white representation of the image.
Pattern Dither
Converts an image by organizing the gray levels into geometric configurations of black and white
dots.
Diffusion Dither
Converts an image by using an error-diffusion process, starting at the pixel in the upper left corner
of the image. If the pixel’s value is above middle gray (128), the pixel is changed to white—if below it, to black.
Because the original pixel is rarely pure white or pure black, error is inevitably introduced. This error is transferred
Because the original pixel is rarely pure white or pure black, error is inevitably introduced. This error is transferred