Adobe PDF conversion settings

Adobe PDF presets

A PDF preset is a group of settings that affect the process of creating a PDF. These settings are designed to balance file size with quality, depending on how the PDF is used. Most predefined presets are shared across Adobe Creative Cloud applications, including InDesign, Illustrator, Photoshop, and Acrobat. You can also create and share custom presets for your unique output requirements. A saved PDF preset file has the suffix .joboptions.

Some of the following presets aren't available until you move them from the default Extras folder to the Settings folder for custom settings.

The Distiller, Extras, and Settings folders for default settings are found at the following locations.

• (Windows 11 (64-bit), Windows 10 version 1810 or later (32-bit and 64-bit), Windows 8, 8.1 (32-bit and 64-bit)†, Windows 7 SP1 (32-bit and 64-bit), or Windows Server - 2008 R2 (64 bit), 2012 (64 bit), 2012 R2 (64 bit)†, 2016 (64 bit), or 2019 (64 bit)) ProgramData/Adobe/Adobe PDF
  

• (Acrobat Pro on macOS) Library/Application Support/Adobe/Adobe PDF

The default settings files installed with Distiller are Read Only and, Hidden.

The custom settings are found in the following locations:

• Users/[user name]/AppData/Roaming/Adobe/Adobe PDF/Settings (Windows 11 (64-bit), Windows 10 version 1810 or later (32-bit and 64-bit), Windows 8, 8.1 (32-bit and 64-bit)†, Windows 7 SP1 (32-bit and 64-bit), or Windows Server - 2008 R2 (64 bit), 2012 (64 bit), 2012 R2 (64 bit)†, 2016 (64 bit), or 2019 (64 bit))
  

• (Acrobat Pro on macOS) Users/[user name]/Library/Application Support/Adobe/Adobe PDF/Settings

Some presets are not available in some Adobe Creative Cloud applications.

Creates PDFs for quality printing on desktop printers and proofing devices. This preset uses PDF 1.4, downsamples color and grayscale images to 300 ppi and monochrome images to 1200 ppi. It also embeds subsets of all fonts, leaves color unchanged, and does not flatten transparency (for file types capable of transparency). These PDF files can be opened in Acrobat 10x and Acrobat Reader 10x and later.

Creates PDFs suitable for viewing and printing engineering drawings larger than 200 x 200 in. (508 x 508 cm). These PDFs can be opened in Acrobat and Acrobat Reader 10.x and later.

Used for long-term preservation (archival) of electronic documents. PDF/A‑1b uses PDF 1.4 and converts all colors to either CMYK or RGB, depending on which standard you choose. These PDFs can be opened in Acrobat and Acrobat Reader versions 10x and later.

PDF/X‑1a requires all fonts to be embedded, the appropriate PDF bounding boxes to be specified, and color to appear as CMYK, spot colors, or both. Compliant files must contain information describing the printing condition for which they are prepared. PDF files created with PDF/X‑1a compliance can be opened in Acrobat 10x and Acrobat Reader 10x and later.

PDF/X‑1a uses PDF 1.3, and downsamples color and grayscale images to 300 PPI and monochrome images to 1200 PPI. It embeds subsets of all fonts, creates untagged PDFs, and flattens transparency using the High-Resolution setting.

Creates PDF files for high-quality print production (for example, for digital printing or for color separations to an imagesetter or platesetter). However, it does not create files that are PDF/X compliant. In this case, the quality of the content is the highest consideration. The objective is to maintain all the information in a PDF file that a commercial printer or print service provider requires to print the document correctly. This set of options uses PDF 1.4, converts colors to CMYK, and downsamples color and grayscale images to 300 ppi and monochrome images to 1200 ppi. It embeds subsets of all fonts and preserves transparency (for file types capable of transparency).

These PDF files can be opened in Acrobat 10x and Acrobat Reader 10x and later.

Note: Before creating a PDF file to send to a commercial printer or print service provider, find out what output resolution and other settings are required. Or, ask for a .joboptions file with the recommended settings. You sometimes must customize the Adobe PDF settings for a particular provider and then provide a .joboptions file of your own.

Creates accessible PDF files that include tags, hyperlinks, bookmarks, interactive elements, and layers. This set of options uses PDF 1.6 and embeds subsets of all fonts. It also optimizes files for byte serving. These PDF files can be opened in Acrobat and Reader 7.0 and later. (The Rich Content PDF preset is in the Extras folder).

Creates PDF files for displaying on the web or an intranet, or for distribution through an email system. This set of options uses compression, downsampling, and a relatively low image resolution. It converts all colors to sRGB, and (for Adobe Acrobat Distiller-based conversions) does not embed fonts. It also optimizes files for byte serving.

These PDF files can be opened in Acrobat and Reader 6.0 and later.

Creates PDF files to be printed to desktop printers or digital copiers, published on a CD, or sent to a client as a publishing proof. This set of options uses compression and downsampling to keep the file size down. However, it also embeds subsets of all (allowed) fonts used in the file, converts all colors to sRGB, and prints to a medium resolution. Windows font subsets are not embedded by default. PDF files created with this settings file can be opened in Acrobat and Reader 6.0 and later.

About PDF/X, PDF/E, and PDF/A standards

PDF/X, PDF/E, and PDF/A standards are defined by the International Organization for Standardization (ISO). PDF/X standards apply to graphic content exchange. PDF/E standards apply to the interactive exchange of engineering documents; PDF/A standards apply to the long-term archiving of electronic documents. During PDF conversion, the file that is being processed is checked against the specified standard. If the PDF does not meet the selected ISO standard, you're prompted to either cancel the conversion or create a non-compliant file.

The most widely used standards for a print publishing workflow are several PDF/X formats: PDF/X‑1a, PDF/X‑3, and (in 2008) PDF/X‑4. The most widely used standards for PDF archiving are PDF/A‑1a and PDF/A‑1b (for less stringent requirements). Currently, the only version of PDF/E is PDF/E-1.

For more information on PDF/X, PDF/E, and PDF/A, see the ISO and AIIM websites.

For details on creating and working with PDF/A files, see www.adobe.com/go/learn_acr_pdfa_en

Customize Adobe PDF settings

You may want to create custom conversion settings for specific jobs or output devices. The selections you make determine whether the document fonts are embedded and subset at 100%. The selections determine how vector objects and images are compressed and sampled. The selections also determine whether the resulting PDF includes high-end printing information, such as OPI (Open Prepress Interface) comments. Default settings files cannot be modified, but can be duplicated to help create new settings files.

Create a custom Adobe PDF settings file

Delete custom Adobe PDF settings files

Adobe PDF settings

The Acrobat Distiller Adobe PDFMaker Settings > Edit Adobe PDF Settings contains panels of options that you can select to customize your PDF output.

General panel options

Use this panel to select a version of Acrobat for file compatibility and other file and device settings.

Sets the compatibility level of the PDF. Use the most recent version (in this case, version 1.7) to include all the latest features and functionality. If you’re creating PDFs that will be distributed widely, choose an earlier level, to ensure that all users can view and print the document.

Compresses structural information (such as bookmarks, accessibility, and noncompressible objects), hiding the information and making it unusable in Acrobat 5.0 or Reader 5.0. Tags Only compresses structural information. Off applies no compression.

Automatically rotates pages according to the direction of text.

Rotates all pages to match the orientation of the majority of text in the document.

Rotates each page based on the orientation of the text on that page.

Prevents pages from rotating.

Specifies whether to display a PDF with left-side or right-side binding. The Binding setting affects the look and feel of pages in the Two-Up Continuous view and the look and feel of thumbnails side by side.

Use for PostScript files to emulate resolutions based on the printer they are printing to. Permitted values range from 72 to 4000. Use the default setting unless you plan to print the PDF on a specific printer while emulating the resolution defined in the original PostScript file.

Specifies which pages to convert to PDF.

Embeds a thumbnail preview for each page in the PDF, increasing the file size. Deselect this setting when users of Acrobat 5.0 and later will view and print the PDF. The versions generate thumbnails dynamically each time you select the Pages panel of a PDF.

Restructures the file for faster access (page-at-a-time downloading, or byte serving) from web servers. This option compresses text and line art, overriding compression selections on the Images panel.

Specifies the page size to use when one is not specified in the original file. EPS files give a bounding box size, not a page size.

Images panel options

The options in the Images panel specify compression and resampling for color, grayscale, and monochrome images. You may want to experiment with these options to find an appropriate balance between file size and image quality.

The resolution setting for color and grayscale images should be 1.5 to 2 times the line screen ruling at which the file will be printed. The resolution for monochrome images should be the same as the output device. However, saving a monochrome image at a resolution higher than 1500 dpi increases the file size without noticeably improving image quality. Images that will be magnified, such as maps, may require higher resolutions.

The following table shows common types of printers and their resolution measured in dpi. It also depicts default screen ruling measured in lines per inch (lpi), and a resampling resolution for images measured in pixels per inch (ppi). For example, if you were printing to a 600-dpi laser printer, you would enter 170 for the resolution at which to resample images.

Reduces image resolutions that exceed the For Images Above value to the resolution of the output device by combining pixels in a sample area of the image to make one larger pixel.

Averages the pixels in a sample area and replaces the entire area with the average pixel color at the specified resolution.

Replaces an entire area with a pixel selected from that sample area, at the specified resolution. Causes faster conversion time than downsampling, but resulting images are less smooth and continuous.

Uses a weighted average, instead of a simple average (as in downsampling) to determine pixel color. This method is slowest but produces the smoothest tonal gradations.

Applies compression to color, grayscale, and monochrome images. For color and grayscale images, also sets the image quality.

Smooths jagged edges in monochrome images. Choose 2 bit, 4 bit, or 8 bit to specify 4, 16, or 256 levels of gray. (Anti-aliasing may cause small type or thin lines to look blurry.)

Opens the Image Policy dialog box, where you can set processing options for Color, Grayscale, and Monochrome images that are less than the resolutions you specify. For each type of image, enter a resolution value, and then choose Ignore, Warn And Continue, or Cancel Job.

Fonts panel options

The Fonts options specify which fonts to embed in a PDF, and whether to embed a subset of characters used in the PDF. You can embed OpenType®, TrueType, and PostScript fonts. Fonts that have license restrictions are listed with a lock icon . If you select a font that has a license restriction, the nature of the restriction is described in the Adobe PDF Options dialog box.

Embeds all fonts used in the file. Font embedding is required for PDF/X compliance.

Embeds all OpenType fonts used in the file, and maintains OpenType font information for advanced line layout. This option is available only if either Acrobat 7 (PDF 1.6) or Acrobat 8 (PDF 1.7) is selected from the Compatibility menu in the General panel.

Specifies a threshold percentage if you want to embed only a subset of the fonts. For example, if the threshold is 35, and fewer than 35% of the characters are used, Distiller embeds only those characters.

Specifies how Distiller responds if it cannot find a font to embed when processing a file.

To embed only certain fonts, move them into the Always Embed list. Make sure that Embed All Fonts is not selected.

Move fonts that you do not want to embed to this list. If necessary, choose a different font folder from the pop-up menu to display the font in the font list.

If the font you want is not in a font folder, click Add Name. Enter the name of the font, select Always Embed List (or Never Embed List), and click Add.

Removes a font from the Always Embed or Never Embed list. This action doesn’t remove the font from your system; it removes the reference to the font from the list.

Color panel options

Whether you’re using color management information in the PostScript file, using Distiller CSFs, or defining custom settings, you set all color management information for Distiller on the Color panel of the Adobe PDF Settings dialog box.

Lists color settings, including those used in graphics applications. The None setting lets you edit the Color Management Policies and Working Spaces settings.

Specifies how Distiller converts unmanaged color in a PostScript file when you don’t use a Distiller color settings file. This menu is available when None is selected in the Settings File menu.

Leaves device-dependent colors unchanged and preserves device-independent colors as the nearest possible equivalent. It's a helpful option for print shops that have calibrated their devices, have used that information to specify color in the file, and are only outputting to those devices.

Tags color objects with an ICC profile and calibrates colors, making them device-independent in PDFs compatible with Acrobat 4 (PDF 1.3) and later. Converts device-dependent color spaces in images (RGB, Grayscale, and CMYK) to device-independent color spaces (CalRGB, CalGray, and Cie L*a*b) in Acrobat 3.0 (PDF 1.2) compatible PDFs.

Tags ICC profiles in images only (not text or vector objects), which prevents black text from undergoing any color shift when distilling Acrobat 4.0 (PDF 1.3) compatible PDFs. Converts device-dependent color spaces in images (RGB, Grayscale, and CMYK) to device-independent color spaces (CalRGB, CalGray, and Lab) in Acrobat 3.0 (PDF 1.2) compatible PDFs.

Calibrates color, making it device-independent. Converts CMYK and RGB images to sRGB in PDFs compatible with Acrobat 4 (PDF 1.3) or later. Converts CMYK and RGB images to calibrated RGB (CalRGB) in Acrobat 3.0 (PDF 1.2) compatible PDFs. Recommended for PDFs that will be used onscreen or with low-resolution printers.

Converts color spaces to DeviceGray or DeviceCMYK according to the options specified in the Working Spaces menu. All Working Spaces must be specified.

Choose a method to map colors between color spaces. The result of any particular method depends on the profiles of the color spaces. For example, some profiles produce identical results with different methods.

Acrobat shares four rendering intents (Perceptual, Saturation, Relative Colorimetric, and Absolute Colorimetric) with other Creative Suite applications.

Acrobat also includes a rendering intent called Preserve, which indicates that the intent is specified in the output device rather than in the PDF. In many output devices, Relative Colorimetric is the default intent.

For all Color Management Policies values other than Leave Color Unchanged, choose a working space to specify which ICC profiles are used for defining and calibrating the grayscale, RGB, and CMYK color spaces in distilled PDFs.

Choose a profile to define the color space of all grayscale images in files. The default ICC profile for gray images is Adobe Gray - 20% Dot Gain. Choose None to prevent grayscale images from being converted.

Choose a profile to define the color space of all RGB images in files. The default, sRGB IEC61966-2.1, is recognized by many output devices. Choose None to prevent RGB images from being converted.

Choose a profile to define the color space of all CMYK images in files. The default is U.S. Web Coated (SWOP) v2. Choose None to prevent CMYK images from being converted.

When selected, device-independent CMYK values are treated as device-dependent (DeviceCMYK) values, device-independent color spaces are discarded, and PDF/X-1a files use the Convert All Colors To CMYK value. When deselected, device-independent color spaces convert to CMYK, if Color Management Policies is set to Convert All Colors To CMYK.

Retains these settings if they exist in the PostScript file. Black generation calculates the amount of black to use when reproducing a color. Undercolor removal (UCR) reduces cyan, magenta, and yellow to compensate for black generation. Because UCR uses less ink, it’s suitable for uncoated stock.

Specifies how to handle transfer functions in PDFs. Transfer functions are used for artistic effect and to correct for the characteristics of a specific output device.

Deletes any applied transfer functions. Applied transfer functions should be removed, unless the PDF is to be output to the same device that the source PostScript file was created for.

Retains the transfer functions traditionally used to compensate for dot gain or dot loss that may occur when an image is transferred to film. Dot gain or loss occurs when the ink dots that make up a printed image are larger or smaller than in the halftone screen.

Applies the transfer function, changing the colors in the file but doesn’t keep it. This method is useful for creating color effects in a file.

Retains any halftone information in files. Halftone information is intended for use with a particular output device.

Advanced panel options

Advanced options specify which Document Structuring Conventions (DSC) comments to keep in a PDF and how to set other options that affect the conversion from PostScript. In a PostScript file, DSC comments contain information about the file (such as the originating application, the creation date, and the page orientation) and provide structure for page descriptions in the file (such as beginning and ending statements for a prologue section). DSC comments can be useful when your document is going to print or press.

For more information, see the documents on the Adobe PDF Technology Center at www.adobe.com/go/learn_acr_pdftechnology_en (PDF, English only).

Uses settings stored in a PostScript file rather than the current PDF settings file. For more information about customizing PDF settings, see the SDK information on the Acrobat and PDFL Developer Guides at www.adobe.com/go/learn_acr_pdftechnology_en (PDF, English only).

PostScript XObjects store fragments of PostScript code to be used when a PDF is printed on a PostScript printer. Use only in controlled workflows where there is no other option. Available when the Standard or Smallest File Size is selected from the Default Settings menu.

Converts blends to smooth shades for Acrobat 4.0 and later, improving quality and reducing file size of PDFs. Distiller converts gradients from Adobe Illustrator, Adobe InDesign, Adobe FreeHand®, CorelDraw, QuarkXPress, and Microsoft PowerPoint.

Reduces the amount of control points used to build curves in CAD drawings, which results in smaller PDFs and faster onscreen rendering.

Uses the copypage operator defined in PostScript Level 2 rather than in Language Level 3 PostScript. If you have a PostScript file and select this option, a copypage operator copies the page. If this option is not selected, the equivalent of a showpage operation is executed, except that the graphics state is not reinitialized.

Retains any overprint settings in files being converted to PDF. Overprint settings create color by printing one ink on top of another ink.

Prevents overprinted objects with zero CMYK values from knocking out CMYK objects beneath them.

Embeds the settings file (.joboptions) used to create the PDF as an attachment. (To view the settings file, choose View > Show/Hide > Navigation Panes > Attachments in Acrobat.)

Processes compressed JPEG images (images that are already compressed using DCT encoding) without recompressing them. When deselected, performance improves because only decompression, not recompression, occurs.

Preserves a PostScript job ticket in a PDF. Job tickets describe the PostScript file and can be used later in a workflow or for printing the PDF.

Sends a prologue and epilogue file with each job. These files can be used to add custom PostScript code you want to run at the beginning or end of every PostScript job being converted.

Sample Prologue.ps and Epilogue.ps files are located in Windows 11 (64-bit), Windows 10 version 1810 or later (32-bit and 64-bit), Windows 8, 8.1 (32-bit and 64-bit)†, Windows 7 SP1 (32-bit and 64-bit), or Windows Server - 2008 R2 (64 bit), 2012 (64 bit), 2012 R2 (64 bit)†, 2016 (64 bit), or 2019 (64 bit)
/Users/[Username]/AppData/Roaming/Adobe/Adobe PDF/Distiller/Data or (Mac OS)/Library/Application Support/Adobe/Adobe PDF/Distiller/Data.

In Windows Explorer (Windows 7 and later), the Application Data folder is typically hidden; to make it visible, choose View> Show, and select Hidden Items. Or, you can type the path into the Address text box.

Maintains DSC information from a PostScript file.

Displays warning messages about problematic DSC comments during processing and adds them to a log file.

Retains information for an EPS file, such as the originating application and creation date.

Retains information needed to replace a For Placement Only (FPO) image or comment with the high-resolution image located on servers that support Open Prepress Interface (OPI) versions 1.3 and 2.0. For more information, see the OPI 2.0 specification at https://www.pdfa.org/norm-refs/5660_OPI_2_0.pdf (PDF, English only).

Retains document properties, such as the title, creation date, and time, in the PDF.

Centers an EPS image and resizes the page to fit closely around the image. If deselected, the page is sized and centered based on the upper left corner of the upper left object and lower right corner of the lower right object on the page. This option applies only to jobs that consist of a single EPS file.

Standards panel options

By using Standards options, you can check document content in the PostScript file to make sure it meets standard PDF/X1-a, PDF/X-3, or PDF/A criteria before creating the PDF. For PDF/X-compliant files, you can also require that the PostScript file meet additional criteria by selecting options in the Standards panel. The availability of options depends on the standard you select. You can also create a PDF/X file from a compliant PDF by using the Preflight feature in Acrobat.

Complies with the PDF/X standard for high-resolution print production.

Complies with the PDF/A standard for archival documents.

Produces a report that indicates whether the file complies with the standard you select, and if not, what problems were encountered. The .log file appears at the bottom of the dialog box.

Specifies whether to create the PDF if the PostScript file does not comply with the requirements of the standard.

Creates a PDF even if the PostScript file does not meet the requirements of the standard, and notes these problems in the report.

Creates a PDF only if the PostScript file meets the requirements of the standard, and is otherwise valid.

Flags the PostScript file as noncompliant if one of the reporting options is selected and a trim box or art box is missing from any page.

Computes values for the trim box based on the offsets for the media box of respective pages if neither the trim box nor art box is specified. The trim box is always as small as or smaller than the enclosing media box.

Uses the media box values for the bleed box if the bleed box is not specified.

Computes values for the bleed box based on the offsets for the trim box of respective pages if the bleed box is not specified. The bleed box is always as large as or larger than the enclosed trim box. This option uses the units specified on the General panel of the Adobe PDF Settings dialog box.

Indicates the characterized printing condition for which the document has been prepared and is required for PDF/X compliance. If a document doesn’t specify an output intent profile name, Distiller uses the selected value from this menu. If your workflow requires the document to provide the output intent, choose None.

Indicates the reference name that is specified by the registry of the output intent profile name. For more information, click the question mark next to the option.

Describes the intended printing condition. This entry can be useful for the intended receiver of the PDF. For more information, click the question mark next to the option.

Indicates the web address for finding more information about the output intent profile. The URL is automatically entered for ICC registry names. The registry name is optional, but recommended. For more information, click the question mark next to the option.

Indicates the state of trapping in the document. PDF/X compliance requires a value of True or False. If the document does not specify the trapped state, the value provided here is used. If your workflow requires that the document provide the trapped state, choose Leave Undefined.

PDF compatibility levels

When you create PDFs, you must decide which PDF version to use. You can change the PDF version by switching to a different preset or choosing a compatibility option when you save as PDF or edit a PDF preset.

Generally speaking, unless there’s a specific need for backward compatibility, you should use the most recent version (in this case version 1.7). The latest version will include all the newest features and functionality. If you’re creating documents to be distributed widely, choose Acrobat 5.0 (PDF 1.4), or Acrobat 6.0 (PDF 1.5) so users can view and print the document.

The following table compares some of the functionality in PDFs created using the different compatibility settings.

Share custom PDF settings

You can save and reuse your own Adobe PDF preset definitions. Share a custom preset by sending a copy of the resulting file to other users to add to Distiller apps installed on their computers.

PDF settings files have the extension .joboptions. Custom preset files are stored in the following locations.

• Windows 11 (64-bit), Windows 10 version 1810 or later (32-bit and 64-bit), Windows 8, 8.1 (32-bit and 64-bit)†, Windows 7 SP1 (32-bit and 64-bit), or Windows Server - 2008 R2 (64 bit), 2012 (64 bit), 2012 R2 (64 bit)†, 2016 (64 bit), or 2019 (64 bit) Users/User/AppData/Roaming/Adobe/Adobe PDF/Settings
  

• (Acrobat Pro for macOS) User/[username]/Library/Application Support/Adobe/Adobe PDF/Settings

The settings file appears as the selected option in the Default Settings menu.

Compressing and downsampling images

When converting PostScript files to PDF, you can compress vector objects (such as text and line art) and compress and downsample images. Line art is described with a mathematical equation and is usually created with a drawing program such as Adobe Illustrator. Images—whether color, monochrome, or grayscale—are described as pixels and are created with applications like Adobe Photoshop or by scanning. Monochrome images include most black-and-white illustrations made by paint programs and any images scanned with an image depth of 1 bit.

When you downsample (or decrease the number of pixels), information is deleted from the image. With Distiller, you specify an interpolation method—average downsampling, bicubic downsampling, or subsampling—to determine how pixels are deleted. Depending on the settings you choose, compression and downsampling can significantly reduce the size of a PDF with little or no loss of detail and precision.

When Distiller processes a file, it normally applies the compression settings to images throughout the file. However, you can assign different compression and downsampling methods to individual images.

Varying the compression and downsampling methods within a PDF

Before you create a PDF, you can take various approaches to applying different compression and downsampling options to the individual images that will go into that PDF:

• Use Adobe Photoshop CC to resample and compress existing image files before using Distiller. When you are ready to create the PDF in Distiller, be careful to deselect the compression and downsampling or subsampling options.

• Create separate PostScript files for each part of the document that you want to process differently, and use different compression options to distil each part. Then use Distiller to merge the files into a single PDF.

• When you create color, grayscale, and monochrome images in an art application (such as Adobe Photoshop CC), select the compression and downsampling settings that you want when you save each image from within that application.

• Insert Distiller parameters before images in a PostScript file. You can use this technique to process every image in a document differently. This technique is the most difficult because it requires knowledge of PostScript programming. For more information on using parameters, see the SDK documentation on the Acrobat Developer Center at https://opensource.adobe.com/dc-acrobat-sdk-docs/acrobatsdk/ (English only).

Compression methods

Distiller applies ZIP compression to text and line art, ZIP or JPEG compression to color and grayscale images, and ZIP, CCITT Group 3 or 4, or Run Length compression to monochrome images.

You can choose from the following compression methods:

Works well on images with large areas of single colors or repeating patterns, and for black-and-white images that contain repeating patterns. Acrobat supports only 8-bit ZIP compression, which is lossless; that is, data is not removed to reduce file size, so image quality is not affected.

Suitable for grayscale or color images, such as continuous-tone photographs. JPEG is lossy, which means that it removes image data and may reduce image quality. However, it attempts to reduce file size with the minimum loss of information. Because JPEG compression eliminates data, it can achieve much smaller file sizes than ZIP compression.

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 images one row at a time.

Produces the best results for images that contain large areas of solid white or black.