Adobe photoshop cs2 사용자 설명서

ADOBE PHOTOSHOP CS2 

When saving artwork in Adobe PDF, you can compress text and line art, and compress and downsample bitmap 
images. Depending on the settings you choose, compression and downsampling can significantly reduce the size of 
a PDF file with little or no loss of detail and precision. 

The Compression area of the Adobe PDF Options dialog box is divided into three sections. Each section provides 
the following options for compressing and resampling color, grayscale, or monochrome images in your artwork. 

If you plan to use the PDF file on the web, use downsampling to allow for higher compression. If 

you plan to print the PDF file at high resolution, do not use downsampling. Deselect the option to disable all 
downsampling options. 

Downsampling refers to decreasing the number of pixels in an image. To downsample color, grayscale, or 
monochrome images, choose an interpolation method—average downsampling, bicubic downsampling, or subsam-
pling—and enter the desired resolution (in pixels per inch). Then enter a resolution in the For Images Above text 
box. All images with resolution above this threshold are downsampled. 

The interpolation method you choose determines how pixels are deleted: 

Averages the pixels in a sample area and replaces the entire area with the average pixel 

color at the specified resolution. Average downsampling is the same as Bilinear resampling. 

Uses a weighted average to determine pixel color, which usually yields better results than 

the simple averaging method of downsampling. Bicubic is the slowest but most precise method, resulting in the 
smoothest gradations. 

Chooses a pixel in the center of the sample area and replaces the entire area with that pixel color. 

Subsampling significantly reduces the conversion time compared with downsampling but results in images that are 
less smooth and continuous. Subsampling is the same as Nearest Neighbor resampling. 

Determines the type of compression that is used. The Automatic option automatically sets the best 

possible compression and quality for the artwork contained in the file. For most files, this option produces satis­
factory results. Use Automatic (JPEG) if you need the greatest compatibility. 

Works well on images with large areas of single colors or repeating patterns, and for black-and-

white images that contain repeating patterns. ZIP compression can be lossless or lossy, depending on the Quality 
setting. 

Is suitable for grayscale or color images. JPEG compression is lossy, which means that it 

removes image data and may reduce image quality; however, it attempts to reduce file size with a minimal loss of 
information. Because JPEG compression eliminates data, it can achieve much smaller file sizes than ZIP 
compression. 

Is the new international standard for the compression and packaging of image data. Like JPEG 

compression, JPEG2000 compression is suitable for grayscale or color images. It also provides additional advantages, 
such as progressive display. 

Are available only for monochrome bitmap images. CCITT (Consultative 

Committee on International Telegraphy and Telephony) compression is appropriate for black-and-white images and 
any images scanned with an image depth of 1 bit. Group 4 is a general-purpose method that produces good 
compression for most monochrome images. Group 3, used by most fax machines, compresses monochrome bitmaps 
one row  at  a time.  Run  Length compression  produces  the best results  for images that contain  large areas  of  solid black  
or solid white. 

Determines the amount of compression that is applied. The available options depend on the 

compression method. For JPEG Compression, Photoshop provides Minimum, Low, Medium, High, and Maximum