Description of the process of creating a graphic file. Basic graphic file formats


The raster format is characterized by the fact that the entire image is divided vertically and horizontally into fairly small rectangles, the so-called image elements, or pixels (from the English pixel-picture element).

The size of the image stored in the file is specified as the number of horizontal and vertical pixels. For example, the optimal resolution for a 15-inch monitor is usually 1024x768.

Raster formats

Main raster formats: GIF, BMP, WBMP, PCX, PCD, PSD, FLM, IFF, PXR, PNG, SCT/PICT, PCT, RAW, TIF/TIFF, BMP, JPEG, TGA, FPX, GIF, PhotoCD, MNG, ICO, FLA/SWF

BMP (from the English Bitmap Picture) is a format for storing raster images. Initially, the format could only store device-dependent rasters (Device Dependent Bitmap, DDB), but with the development of technologies for displaying graphic data BMP format began to primarily store device-independent rasters (English: Device Independent Bitmap, DIB).

Works with BMP format great amount programs, since its support is integrated into operating Windows systems and OS/2. BMP files can have extensions .bmp, .dib and .rle. In addition, data in this format is included in binary files RES resources and PE files.

Developed by Microsoft to be compatible with all Windows applications. The BMP format can save black-and-white, grayscale, index color, and RGB color images (but not two-tone or CMYK color images). The disadvantage of these graphic formats: large volume. The consequence is low suitability for Internet publications.

Photoshop 7 in the Save for Web module can save images in the Wireless Bitmap (WBMP) format, specially optimized for cell phones, smartphones, PDAs and others mobile devices. A description of this format, along with the WML (Wireless Markup Language) markup language, is included in the WAP (Wireless Application Protocol) specification. In addition to Photoshop, Macromedia Fireworks 4 and higher can also create WBMP images. The format only supports two colors, but more can be simulated using pixel spread. In theory, WBMP files can contain animation. Compression is not supported, which is very surprising, since in practice a graphic file for WAP cannot be larger than 1461 bytes (this limitation is due to the small memory capacity of cell phones). Due to the modest resolution of mobile device displays, safe file sizes are limited to 90x24 pixels. In addition to the above disadvantages, WBMP is still quite crude: only a few devices are capable of displaying graphics in this format.

GIF (Graphics Interchange Format - a format for exchanging images). GIF is a format for storing graphic images. The GIF format is capable of storing compressed data without loss of quality in a format of no more than 256 colors. Independent of hardware The GIF format was developed in 1987 (GIF87a) by CompuServe for transmitting raster images over networks. In 1989, the format was modified (GIF89a), support for transparency and animation was added. GIF uses LZW compression, which makes it possible to compress files with a lot of uniform fills (logos, inscriptions, diagrams) well.

GIF is widely used on World Wide Web pages.

The GIF format allows interlaced data storage. This splits the lines into groups and changes the order in which the lines are stored in the file. When loading, the image appears gradually, in several passes. Thanks to this, having only part of the file, you can see the entire image, but with a lower resolution.

Animated images

The GIF format supports animated images. Fragments are sequences of several static frames, as well as information about how long each frame will be shown on the screen. The animation can be looped, then after the last frame the first one will be shown again and so on.

Patent protection

GIF was originally a proprietary format, but its patent protection has expired. In the US, the patent expired on June 20, 2003. The Canadian patent expired on July 7, 2004. The patent expired for the UK, France, Germany and Italy on June 18, 2004, and for Japan on June 20, 2004.

Jpeg (pronounced “japeg”, English Joint Photographic Experts Group, after the name of the development organization) is one of the popular graphic formats used for storing photographs and similar images. Files containing JPEG data typically have the extensions .jpeg, .jfif, .jpg, .JPG, or .JPE. However, of these, .jpg is the most popular extension on all platforms. The MIME type is image/jpeg.

The JPEG algorithm is a lossy data compression algorithm.

The JPEG algorithm is most suitable for compressing photographs and paintings containing realistic scenes with smooth transitions of brightness and color. JPEG is most widely used in digital photography and for storing and transmitting images using the Internet.

On the other hand, JPEG is unsuitable for compressing drawings, text and character graphics, where the sharp contrast between adjacent pixels leads to noticeable artifacts. JPEG (like other distortion compression methods) is not suitable for compressing images during multi-stage processing, since distortions will be introduced into the images each time intermediate processing results are saved.

Advantages and disadvantages

The disadvantages of compression according to the JPEG standard include the appearance of characteristic artifacts in restored images at high compression rates: the image is scattered into blocks of 8x8 pixels (this effect is especially noticeable in areas of the image with smooth changes brightness), in areas with high spatial frequency (for example, on contrast contours and image boundaries), artifacts appear in the form of noise halos. It should be noted that the JPEG standard (ISO/IEC 10918-1, Annex K, clause K.8) provides for the use of special filters to suppress blocking artifacts, but in practice such filters, despite their high efficiency, are practically not used. However, despite its shortcomings, JPEG has become very widespread due to its fairly high (relative to the alternatives that existed at the time of its appearance) compression ratio, support for compression of full-color images, and relatively low computational complexity.

Designed to present complex photographic images. Animation or transparent color format are not supported.

The main thing is to choose the maximum compression with minimal loss of quality. JPEG is less suitable for processing black-and-white halftone images), which leads to a significant reduction in file size. Thus, unlike the LZW or RLE compression method, as a result of using JPEG technology, data is lost forever. Thus, a file once written to JPEG format, and then translated to, say, TIFF, will no longer be the same as the original.

The most suitable format for posting full-color images on the Internet. It is likely that until the advent of powerful lossless image compression algorithms, it will remain the leading format for presenting photographs on the Web.

JPEG 2000 (or jp2) is a graphic format that, instead of the discrete cosine transform characteristic of JPEG, uses wavelet transform technology, based on representing the signal as a superposition of some basic functions-- wave packets.

As a result of this compression, the image is smoother and clearer, and the file size compared to JPEG with the same quality is reduced by another 30%. JPEG 2000 is completely free from the main drawback of its predecessor: thanks to the use of wavelets, images in this format do not contain the famous “grid” of blocks of 8 pixels. The new format, like JPEG, supports so-called “progressive compression”, which allows you to see an initially blurry, but then increasingly clear image as it loads.

This format is not yet widespread and is not supported by everyone. modern browsers. jp2 supports include Safari and Mozilla Firefox (via Quicktime)

Although JPEG 2000 supports lossless compression, it is not intended to improve upon the best lossless compression format.

PNG (portable network graphics) is a raster format for storing graphic information that uses lossless compression using the Deflate algorithm.

PNG was created as a free format to replace GIF, so the backronym “PNG's Not GIF” appeared on the Internet.

PNG files typically have a .PNG (.png) extension and use the image/png MIME type notation.

It was created specifically for the Internet as a replacement for the first two formats and, thanks to the patent policy, Compuserve is gradually replacing GIF. Allows you to select a saving palette - gray halftones, 256 colors, true color. Depending on the properties of the image, it is indeed sometimes preferable to GIF"a or JPG"a. Allows you to use a “transparent” color, but, unlike GIF, there can be up to 256 such colors. Unlike GIF, compression without loss of quality is performed both horizontally and vertically (the algorithm is its own, the parameters are also not adjustable).

Today's most progressive format graphics for the Network are png (Portable Network Graphics, read “ping”). Originally intended to replace the obsolete gif on the artificial landscapes of the Web, png offers a whole range of new features, the lack of which in gif did not suit many.

This is a fairly “young” format for Web graphics, competing with GIF. PNG is the only format common on the Internet that allows you to obtain full-color images from transparent background. The PNG format uses a powerful lossless compression algorithm based on the popular LZW compression. Being a Web-centric format, PNG does not support multi-channel images, color profiles, or clipping paths.

There are two subformats: PNG8 and PNG24, the numbers indicate the maximum color depth possible in the subformat. Does not support animation.

Why has such a wonderful and convenient format not become widespread? The fact is that our “most beloved” company Microsoft considered this format unpromising due to the fact that it was not developed by them.

PNG format positioned primarily for use on the Internet and graphics editing.

PNG supports three main types of raster images. Halftone image, color indexed image, full color image.

The PNG format stores graphic information in a compressed form. Moreover, this compression is performed without losses, unlike, for example, JPEG with losses.

The PSD (PhotoShop Document) format is a proprietary format of Adobe Photoshop. The only format that supports all program features. It is preferable for storing intermediate results of image editing, as it preserves their layer-by-layer structure. All recent versions of Adobe Systems products support this format and allow you to import Photoshop files directly. The disadvantages of the PSD format include insufficient compatibility with other common applications and the lack of compression capabilities.

All color models and any color depth from white-black to true color are supported, lossless compression.

TIFF format (Tagged Image File Format) was created by the combined forces of such giants as Aldus, Microsoft and Next specifically for storing scanned images. TIFF is one of the oldest formats in the world of microcomputers; today it is the most flexible, universal and actively developing. It can store graphics in any mode: from bit and indexed colors to Lab, CMYK and RGB (except duplex and multi-channel documents).

Although much time has passed since its creation, TIFF is still the main format used for storing scanned images and placing them in publishing systems and illustration programs. Versions of the format exist on all computer platforms, making it extremely convenient for transferring bitmaps between them. It allows you to store clipping paths, calibration information, and printing parameters. Any number of additional alpha channels can be used. Additional color channels are not supported. The great advantage of the format is its support for almost any compression algorithm. The most common is lossless compression using the LZW (Lempel Ziv Welch) algorithm, which provides a very high degree of compression. By the way, the same algorithm is used by numerous compression programs general purpose that support the ZIP format.

ICO is a format for small pictures (icons) on the WWW. Images are used by browsers to mark Web projects in the URL bar and in favorites. Supported and used by programs for creating icons like IconXP.

(RAW Image Data)

The format is designed for digital cameras. This is an exact copy of the image captured on the matrix during shooting; it consists of three photographs taken in red, blue and green colors.

RAW file extensions may vary from manufacturer to manufacturer, and they cannot always be opened using image processing programs.

Although if a camera supports saving RAW, then, as a rule, it comes with some kind of program for processing files of this format.

Doesn't support anything. That is, completely. Even data on the number of channels, color depth and resolution is not stored, so during opening you will have to enter these parameters manually, from memory.

PCX (PC eXchange) format - one of the first raster formats, created by ZSoft for the PC Paintbrush program. Supports monochrome, indexed and full color RGB images. Additional color and alpha channels, clipping paths, and color management are not supported. The format involves the use of the simplest compression algorithm (Run Length Encoding, RLE) without loss of information. Nowadays it has mainly historical significance. The pcx format also once raised its palm in primitivism: it is almost as simple inside as bmp. This format has the same capabilities as bmp, but does not support OS/2. But pcx can be viewed with most DOS programs, including the internal Norton Commander viewer.

The PCD (Photo CD) format was developed by Kodak for storing scanned photographic images. Scanning is performed on special equipment (Kodak, PIW workstations), and the result is recorded on a special format CD, Kodak Photo CD. It can be viewed using industrial video players and game consoles on a regular TV. In practice, Photo CDs are more often used in publishing technologies as a source of images. Most photo library manufacturers use this format on their CDs. Images on the Photo CD are presented in a special YCC color model developed by Kodak specialists and in many ways similar to the Lab model. YCC also has three basic components, luminance and two chromatic. Because the eye is more sensitive to luminance than to color, half of the color information is discarded during scanning: for every two pixels there is only one chromatic component value. This reduces the amount of graphics data and the size of the PCD file. To further reduce file sizes, a conventional lossless LZW compression scheme is used. There are several Photo CD formats. The Master Photo CD format contains images scanned from regular 35mm film. The Master Pro Photo CD format (120 mm and 4x5 inches) is addressed to professional photographers. The Print Photo CD format is intended for printing applications. The original is scanned by professional scanners (Crosfield, Linotype, Scitex) and saved with uncompressed resolution. The Catalog Photo CD format allows up to 4,500 native resolution images to fit onto one disc. And finally, the Portfolio PhotoCD format is aimed at multimedia applications. A CD of this format can contain up to 800 images, as well as sound and interactive scenarios.

Enough old format TGA (Targa) was created specifically to work with graphic accelerator TrueVision. This accelerator is widely used by applications on the DOS platform. The format supports 24-bit and 32-bit RGB images with one alpha channel, as well as grayscale, indexed, and 16-bit RGB images without alpha channels. Clipping paths and color profiles are not supported. The targa (Truevision Targa Image File) format is also respected among DOS programs. Targa files were often used by the DOS version of 3DStudio Max to store textures.

The abundance of images used on computers can be divided into three large groups. First of all, 2D graphics, in which flat (without a third coordinate) images are created; this group includes raster and vector graphics. Then 3D graphics and motion graphics.

Since images are created using special tools - graphic editors - it is impossible to consider file formats without taking into account their features. First of all, what is a graphics file? In the most general case, this is the system of image information adopted in a given graphics editor and the method of saving (recording) it. Such an information system can contain both general data (representation of an image on a particular display device, size, resolution, type of printer for printing, degree and method of information compression), and data that is specific and unique. Such data is created during the image editing stage and is intended for subsequent use during editing. For example, CorelDraw files contain information about curves, Photoshop files contain information about layers, channels, etc. Each graphic editor encodes this information in a certain way when recording (saving) on ​​a medium. Thus, the graphic file format should be understood as a set of information about the image and the method of recording it in the file. In general, all graphic formats can be divided into two groups. General-purpose formats contain only the image itself and are intended for storing, transferring or viewing images (gif, tiff, jpeg, etc.) and specific formats intended for storing intermediate results of image editing (cdr, cpt, psd, ai, etc.).

Let us dwell in more detail on the 2D group due to its greatest prevalence. A raster graphics image is an ordered array of unit elements (pixels for a monitor or dots for a printer) containing color information. The number of such elements is determined by the image size and resolution, and the file size additionally depends on the color palette used (black and white or 1-bit, grayscale and 256 colors or 8-bit, high color or 16-bit, true color or 24-bit ). Vector graphics contain mathematical descriptions of the curves and fills (areas filled with a single color and areas of gradients) that make up an image. The issue of resolution and color palette is decided immediately before the file is output to a specific physical device and taking into account its characteristics. In the printing industry, this process is known as RIP - rasterizing an image process.

File compression. Since graphic files usually have big size, the ability to compress (pack) information is useful. There are currently two known compression methods - lossless and lossy. Lossless compression algorithms are similar to those of conventional archivers (LZH, PKZIP, ARJ). The most famous of them, LZW (LZ84), is widely used in the popular raster formats GIF and TIFF. Lossy compression algorithms discard information that is not perceptible to humans (JPEG, PCD). The degree of compression in this case is much higher, but occurs more slowly and can lead to deterioration in quality (depending on the selected compression ratio). The main disadvantage of this algorithm is the impossibility of recompression without significant loss of the original image quality. Therefore, it is recommended to save only the final editing results in JPEG format, and in no case intermediate ones.


General purpose formats

Microsoft Windows Bitmap (BMP)

A format for storing raster graphics in a Microsoft Windows environment (for example, screen wallpapers and screensavers). Supports 1-, 4-, 8-, 24-bit color. Allows compression without loss of quality.

Kodak Photo CD (PCD).

The developer is Kodak. The format is intended for storing slides and negatives captured using a Kodak Photo CD type camera. Each file stores 5 copies of one image of different sizes and qualities from 192x192 to 3072x2048 pixels. It is impossible to programmatically record a PCD image on a computer; you can only import the image into a graphics editor that supports this format.

Zsoft PC PaintBrush (PCX)

One of the oldest and most famous storage formats raster graphics. It appeared almost along with personal computers, due to which it is the most common and is supported by almost all image viewing/editing programs. Uses the simplest lossless compression algorithm RLE.

Tag Image File Format (TIFF)

Developers: Aldus and Microsoft. A universal format for storing raster graphics, widely used in publishing. It is necessary to make a reservation that there are quite a lot of its varieties, due to different compression algorithms. The format that uses the LZW algorithm has the greatest compatibility. The format supports 24 and 32-bit color (CMYK), two types of recording IBM PC and Macintosh, and can store information about masks (selected areas of the image).

TrueVision TGA (TGA)

Developed by TrueVision. The format is used for storing raster graphics and has an interesting feature - along with support for 24-bit color, it has another 8 bits for each single image element to store additional information. In particular, it may contain a mask, which is used in video editing programs, for example, to create an overlay of two sequences of frames. It has been known for a long time and is supported by many graphics packages.

Graphics Interchange Format (GIF)

Developed by CompuServe Corporation in 1987 for storing raster graphics. Implemented one of the most effective LZW compression methods for its time (87g). Allows you to display an image on the screen in four passes, allowing you to preview the image before its final drawing. In 1989 it appeared a new version GIF 89a. This format supports saving multiple images, animation sequences, and transparency colors in one file for the purpose of overlaying images on top of each other. Still widely used for storing and transferring small images (page design elements) to World Wide Web.

Joint Photographic Experts Group (JPEG)

The raster format owes its popularity to the high degree of compression of the source image, based on a lossy compression algorithm. However, this applies primarily to 24- and 8-bit images. There are several varieties, due to different compression algorithms and display methods (gradual rendering is similar to gif). Also widely used on the WWW, mainly for transmitting large images.


Specific formats

As mentioned above, this group of formats is intended mainly for “internal” use (storing intermediate results of image editing). In addition to information about the image itself, the files contain a lot of service data that cannot be correctly interpreted by other viewing/editing programs. Such data may include information about fonts, layers, selections (masks), curves, special effects, etc. The most common formats are for vector graphics - cdr (Corel Draw) and ai (Adobe Illustrator), for raster graphics - psd (Adobe Photoshop ) and cpt (Corel PhotoPaint). Typically, the final image (ie the image intended for publication) is imported into one of the general purpose formats depending on the purpose of publication (gif or jpeg for the Internet, tiff for publishing systems, etc.).

Igor Sivakov

Graphic file formats. Raster and vector formats.

TIFF format

TIFF(English Tagged Image File Format) - a format for storing raster graphic images. TIFF has become a popular format for storing images with high color depth. It is used in scanning, faxing, text recognition, printing, and is widely supported by graphics applications.

Structure The format is flexible and allows you to save images in paletted color mode, as well as in various color spaces:

  • Binary (two-color, sometimes called black and white)
  • Halftone
  • With indexed palette
  • CMYK
  • YCbCr
  • CIE Lab

8, 16, 32 and 64 bits per channel modes are supported.

Compression. It is possible to save an image in a TIFF file with or without compression. Compression levels depend on the characteristics of the image being saved, as well as on the algorithm used. The TIFF format allows the following compression algorithms:

  • PackBits (RLE)
  • Lempel-Ziv-Welch (LZW)
  • LZ77
  • JBIG
  • JPEG
  • CCITT Group 3, CCITT Group 4

The CCITT Group 3, CCITT Group 4 algorithms were originally developed for fax networks (hence why they are sometimes called Fax 3, Fax 4). Currently they are also used in printing, digital mapping systems and geographic information systems.

TIFF is a tagged format and uses basic, extended and special tags:

Basic tags form the core of the format and must be supported by all products that implement the TIFF format according to the specification. Support for extended tags, unlike basic tags, is optional.

JPEG format

JPEG(English: Joint Photographic Experts Group, after the name of the developer organization) is one of the popular graphic formats used for storing photographic images. Files containing JPEG data typically have the extensions .jpeg, .jfif, .jpg, .JPG, or .JPE. The JPEG algorithm allows for both lossy and lossless image compression.

The JPEG algorithm is most suitable for compressing photographs and paintings containing realistic scenes with smooth transitions of brightness and color. JPEG is most widely used in digital photography and for storing and transmitting images using the Internet.

On the other hand, JPEG of little use for compressing drawings, text and character graphics where sharp contrasts between adjacent pixels result in noticeable artifacts. It is advisable to save such images in lossless formats such as TIFF, GIF or PNG.

JPEG (as well as other distortion compression methods) doesn't fit for image compression during multi-stage processing, since distortions will be introduced into the images each time intermediate processing results are saved. JPEG should not be used in cases where even minimal losses are unacceptable, for example, when compressing astronomical or medical images.

TO shortcomings compression according to the JPEG standard should include the appearance of characteristic artifacts in restored images at high compression rates: the image is scattered into blocks of 8x8 pixels (this effect is especially noticeable in image areas with smooth changes in brightness), in areas with high spatial frequency (for example, on contrasting contours and image boundaries), artifacts appear in the form of noise halos.

However, despite its shortcomings, JPEG received very wide use due to a fairly high compression ratio, support for compression of full-color images and relatively low computational complexity.

PDF format

PDF(English: Portable Document Format) is a cross-platform electronic document format created by Adobe Systems using a number of features of the PostScript language. Most often, a PDF file is a combination of text with raster and vector graphics, less often - text with forms, JavaScript, 3D graphics and other types of elements. First of all intended for electronic submission printing products, - a significant amount of modern professional printing equipment can process PDF directly. You can use the official free program to view Adobe Reader, as well as third-party programs. The traditional way to create PDF documents is virtual printer, that is, the document as such is prepared in its own specialized program- a graphics program or text editor, CAD, etc., and then exported to PDF format for electronic distribution, transfer to a printing house, etc. PDF.

The PDF format allows you to embed the necessary fonts (line-by-line text), vector and raster images, forms and multimedia inserts. Supports RGB, CMYK, Grayscale, Lab, Duotone, Bitmap, several types of raster information compression. It has its own technical formats for printing: PDF/X-1, PDF/X-3. Includes mechanism electronic signatures to protect and verify the authenticity of documents. Distributed in this format a large number of accompanying documentation.

CALS format

Raster CALS format(English Computer Aided Acquisition and Logistics Support) standard developed by a division of the US Department of Defense to standardize the exchange of graphic data in electronic form, especially in the areas of technical graphics, CAD/CAM and image processing applications.

CALS is a well-documented, if unwieldy, format that attempts to cover a lot of ground. If you are not familiar with US government documents, you may find working with this format quite difficult. The CALS raster format is required in most applications that process US government documents. Since all data has a byte organization, problems like “from which end to break an egg, blunt or sharp,” never arise.

Characteristics of the CALS format

  • Type - Bitmap (bit matrix)
  • Color - monochrome
  • Compression - CCITT Group 4 or no compression
  • Maximum image size - unlimited
  • Multiple images per file - yes, Type II only
  • Platforms - everything

BMP format

BMP(from the English Bitmap Picture) is a raster image storage format developed by Microsoft. A huge number of programs work with the BMP format, since its support is integrated into OS Windows and OS/2. BMP files can have extensions .bmp, .dib and .rle.

Color depth in this format can be 1, 2, 4, 8, 16, 24, 32, 48 bits per pixel, but 2 bits per pixel depth is not officially supported. In this case, for color depths less than 16 bits, a palette with full-color components with a depth of 24 bits is used. In the BMP format, images can be stored as is or using some common compression algorithms. In particular, the BMP format supports RLE compression without loss of quality, and modern operating systems and software allow the use of JPEG and PNG.

PCX format

PCX(PCExchange) - a standard for the presentation of graphic information, a not so popular analogue of BMP, although it is supported by specific graphic editors such as Adobe Photoshop, Corel Draw, GIMP, etc. Currently, it is practically replaced by formats that support better compression: GIF, JPEG and PNG .

Format type- raster. Most files of this type use a standard color palette, but the format has been expanded to accommodate 24-bit images. PCX is a hardware-dependent format. Designed to store information in a file in the same form as in the video card. For compatibility with older programs, the video controller must support EGA mode. This compression algorithm is very fast and takes small volume memory, however, is not very efficient, impractical for compressing photographs and more detailed computer graphics. Lossless compression is used. When saving an image, successive pixels of the same color are combined and instead of specifying the color for each pixel, the color of the group of pixels and their number are indicated. This algorithm compresses images well that contain areas of the same color.

Advantages of the format

  • the ability to create a limited color palette (for example, 16 or 256 colors);
  • supported by a large number of applications.

Disadvantages of the format

  • does not support color systems other than RGB;
  • Numerous options, especially when working with colors, can make working with the file impossible;
  • an inconvenient compression scheme may actually increase the size of some files.

PNG format

PNG(English portable network graphics) - a raster format for storing graphic information that uses lossless compression.

Application area

The PNG format is designed to replace older and more simple format GIF, and also, to some extent, to replace the much more complex TIFF format. PNG format positioned first of all for use on the Internet and graphics editing.

PNG supports There are three main types of raster images:

  • Halftone (16-bit color depth)
  • Color indexed image (8-bit palette for 24-bit color)
  • Full color image (48-bit color depth)

The PNG format stores graphic information in compressed form. Moreover, this compression is performed without losses, unlike, for example, JPEG with losses.The PNG format has more high degree compression for files with more colors than GIF, but the difference is about 5-25%, which is not enough for the absolute dominance of the format, since the GIF format compresses small 2-16 color files with no less efficiency.

PNG is good format for image editing, even for storing intermediate stages of editing, since image restoration and resaving takes place without loss of quality.

Animation

There is one feature of GIF that is not implemented in PNG - support multiple image, especially animation; PNG was originally designed to just store one image in one file.

Sun Raster Format

Image format Sun Raster This is the native raster format of Sun Microsystems platforms using the SunOS operating system. This format supports black-and-white, grayscale, and color raster data of arbitrary color depth. The use of color maps and simple Run-Length data compression are also supported. Typically, most images in the SunOS operating system are in the Sun Raster format. This format is also supported by most UNIX image processing programs.

Characteristics Sun Raster format

  • Type - bitmap (bit matrix)
  • Colors - various
  • Compression - RLE
  • Multiple images per file - not supported
  • Platform - SunOS
  • Applications - many UNIX applications

Graphic file formats

Information in the section on Wikipedia materials

  • introduce students to the basic raster image formats;
  • introduce the possibility of format conversion;
  • teach how to choose the optimal parameters when scanning images.

Transferring images from one program to another is the same throughout the diverse world of digital images, since each program has its strengths and weaknesses. To take advantage strengths programs, images must be exported quickly and efficiently. To optimize this process, developers software created species computer files- formats.

There is a huge variety various formats graphic files. In order to be able to solve the problems of image portability from one program to another and compressing them in order to save disk space, as well as to find the optimally suitable graphic format for further image processing, let’s get acquainted with some of the most common ones.

Native file formats

Native format - usually a proprietary format created specifically for software application. In most programs, this format is the most effective means when saving files during editing, but not portable (or partially portable) to other applications.

The "native" format for CorelDRAW is CDR, which is most often used. For Microsoft Word own format is DOC, for Adobe Flash - FLA format, etc. For graphic editor Adobe Photoshop's own format is PSD, in which you can save not only graphic information, but also layers and channels. Adobe Photoshop is undoubtedly the most famous image editing tool in the world. The popularity of Photoshop has forced other graphics programs to support PSD format, so artists can export and import files into Photoshop without having to first convert them to a common file format.

There are a large number of standard raster graphics formats. Let's consider only the most common of them.

BITMAP

BITMAP (bit map) is one of the first raster formats. The format is distinguished by a very large file size, since data is recorded for each pixel separately. It is an extremely simple structure and serves to describe and visualize small pictogram images (icons) widely used in graphical interfaces Windows and is also used in multimedia presentations.

There are several varieties of this format. We are most familiar with the *.bmp extension, which supports data up to 24 b/p.

GIF

The GIF (Graphics Interchange Format) raster format was developed by CompuServe Inc. in 1987 to provide compression for color raster files downloaded via telephone line and in computer networks.

The GIF format can only store color depth data from 1 to 8 b/p. GIF uses a very efficient archiver. The format is widely used on Web pages for images with a small number of colors (signs, logos, buttons, design elements). Multimedia programs also allow you to insert images in GIF format.

Features of the format: the image is drawn from top to bottom with changes in clarity and detail (option - interlacing), the format allows you to set a transparent area or define a transparent color, which allows you to place images on any background.

The possibilities for reducing file size are not limited to compression; GIF allows you to arbitrarily set the size of the palette used in the image (other formats, as a rule, have only standard color depth options). Disadvantages of the format usually include the limited number of possible colors.

The format allows you to store a large number of images - frames, so GIF can also be considered as an animation format.

JPEG

The JPEG format was created by the standards committee Joint Photographic Experts Group(Joint Photographic Experts Group) in 1987 to store photorealistic images - photographs. Based on the characteristics of human vision, this format uses lossy compression algorithms and provides significant file reduction. JPEG compression is called lossy - image data is lost when the file is compressed, causing degradation in image quality.

The user has the ability to adjust the degree of compression (respectively, the level of quality). If the user specifies high quality, less compression occurs. When the high compression setting is used, the file size is small, but the image quality suffers more. Almost all programs, when saving in this format, provide the ability to preview the result to obtain a compromise solution between quality and file size.

The JPEG format supports color depth up to 24 b/p. Because the format has a very small file size, it has become widespread in Web publications and image libraries when multi-color photorealistic images are required.

PNG

The PNG (Portable Network Graphics) format is specially created for placing graphics on Web pages. This format is young and combines the advantages of GIF and JPEG formats. It allows you to significantly compress an image file without losing quality, but is not limited to a palette of 256 colors, supports 8, 24 and 32 (24 b/p plus alpha channel) b/p.

This format uses a compression method in which information that is poorly perceived by the human eye is removed from the image. The compression level can be varied from low, when distortion is minimal, to high, when the image may undergo noticeable changes.

The PNG format does not support transparency, but can include a single alpha channel that makes part of the image transparent in a browser that supports PNG channels. Like GIF, it provides step-by-step display with interlaced scanning.

TIFF

One of the most common raster formats used in preparing images for printing is TIFF (Target Image File Format), created by Aldus Corporation in 1986 to overcome the difficulties that arose when transferring graphics files from IBM-compatible computers to Macintoshes and vice versa.

TIFF supports several compression schemes and special image management functions. LZW compression is a non-lossy data compression scheme - when a file is compressed, no data is destroyed and no degradation in quality should occur.

TIFF today is a standard file format supported by most graphics and image processing programs, as well as layout software packages. The format supports data up to 32 b/p. TIFF allows you to save an alpha channel with an image. IN latest versions Adobe Photoshop program this format allows you to save documents with layers.

TIFF has become a common format for image capture systems from scanners and is used in publishing systems. The format is portable between platforms and easily imported into all layout programs, which makes it indispensable when preparing documents for printing.

File formats are the basis of working with digital photographs. will tell you about all the major graphic file formats.

RAW.

A file format containing raw information coming directly from the camera sensor. These files are not processed by the camera's processor (unlike JPG) and contain original shooting information. RAW can be compressed without losing quality.

The advantages of RAW are obvious - unlike JPG, which was processed in the camera and already saved with data compression - RAW gives the widest possibilities for processing photographs and maintains maximum quality.

The note. Different camera manufacturers use different algorithms to create RAW in their cameras. Each manufacturer comes up with its own resolution for its RAW file - NEF - Nikon, CR2 - Canon...

JPEG (aka JPG).

This is the most common graphics file format.

JPG has earned its popularity due to its flexible data compression capabilities. If necessary, the image can be saved with maximum quality. Or compress it to minimum size file for transfer over the network.

JPG uses a lossy compression algorithm. What does this give us? An obvious disadvantage of such a system is the loss of image quality every time a file is saved. On the other hand, image compression simplifies data transfer by 10 times.

In practice, saving a photo with a minimum degree of compression does not result in any visible degradation in image quality. That is why JPG is the most common and popular format storing graphic files.

TIFF.

The TIFF format is very popular for storing images. It allows you to save photos in various color spaces (RBG, CMYK, YCbCr, CIE Lab, etc.) and with high color depth (8, 16, 32 and 64 bits). TIFF is widely supported by graphics applications and is used in the printing industry.

Unlike JPG, a TIFF image will not lose quality every time the file is saved. But, unfortunately, it is precisely because of this that TIFF files weigh many times more than JPG.

Right to TIFF format this moment owned by Adobe. Photoshop can save TIFF without merging layers.

PSD.

The PSD format is used in Photoshop program. PSD allows you to save a raster image with many layers, any color depth and in any color space.

Most often, the format is used to save intermediate or final results of complex processing with the ability to change individual elements.

PSD also supports compression without loss of quality. But the abundance of information that may contain PSD file, greatly increases its weight.

BMP.

The BMP format is one of the first graphic formats. It is recognized by any program that works with graphics; format support is integrated into the Windows and OS/2 operating systems.

BMP stores data with a color depth of up to 48 bits and a maximum size of 65535x65535 pixels.
At the moment, the BMP format is practically not used either on the Internet (JPG weighs several times less) or in printing (TIFF copes with this task better).

GIF.

The GIF format was created in the early days of the Internet for sharing images. It can store lossless compressed images in up to 256 colors. The GIF format is ideal for drawings and graphics, and also supports transparency and animation.
GIF also supports compression without loss of quality.

PNG.

The PNG format was created to both improve and replace the format GIF graphic format that does not require a license for use. Unlike GIF, PNG has alpha channel support and the ability to store an unlimited number of colors.

PNG compresses data without loss, which makes it very convenient for storing intermediate versions of image processing.

JPEG 2000 (or jp2).

A new graphics format created to replace JPEG. For the same quality, JPEG 2000 file size is 30% smaller than JPG.

When highly compressed, JPEG 2000 does not break the image into squares characteristic of the JPEG format.

Unfortunately, at the moment this format is not very widespread and is supported only by Safari and Mozilla/Fireox browsers (via Quicktime).


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