Raster graphics - basic concepts of raster graphics. Raster graphics

Raster graphics

Raster graphics storage scheme.

Raster image- is a grid of pixels or colored dots (usually rectangular) on a computer monitor, paper and other display devices and materials (raster).

Important image characteristics are:

Raster graphics are edited using raster graphics editors. Raster graphics are created using cameras, scanners, directly in a raster editor, also by exporting from a vector editor or as a screenshot.

Advantages

Raster graphics allow you to create (reproduce) almost any drawing, regardless of complexity, unlike, for example, vector graphics, where it is impossible to accurately convey the effect of the transition from one color to another without loss in file size.
Prevalence - raster graphics are now used almost everywhere: from small icons to posters.
High speed of processing complex images if scaling is not needed.
Raster image representation is natural for most I/O devices graphic information, such as monitors (except vector), dot matrix and inkjet printers, digital cameras, scanners, and cell phones.

Flaws

Large file sizes for simple images.
Impossibility of perfect scaling.
Inability to print to plotter.

Because of these shortcomings, it is recommended to use vector graphics instead of even compressed raster graphics to store simple drawings.

Formats

Bitmap images are usually stored in compressed form. Depending on the type of compression, it may or may not be possible to restore the image exactly as it was before compression (lossless compression or lossy compression, respectively). The graphic file can also store additional information: about the author of the file, the camera and its settings, the number of dots per inch when printing, etc.

Lossless compression

Uses compression algorithms based on reducing information redundancy.

BMP or Windows Bitmap - usually used without compression, although the RLE algorithm is possible.
GIF (Graphics Interchange Format) is a legacy format that supports no more than 256 colors at a time. Still popular due to its support for animation, which pure PNG lacks, although software is starting to support APNG.
PCX is an outdated format that allows for good compression of simple drawing images (when compressing, groups of consecutive pixels of the same color are replaced with a record of the number of such pixels and their color).
PNG (Portable Network Graphics)

Lossy compression

It is based on discarding part of the information (usually the least perceived by the eye).

JPEG is a very widely used image format. Compression is based on averaging the color of neighboring pixels (brightness information is not averaged) and discarding high-frequency components in the spatial spectrum of an image fragment. When examining a highly compressed image in detail, blurring of sharp boundaries and characteristic moire near them are noticeable.

Miscellaneous

TIFF supports a wide range of color depths, different color spaces, different compression settings (both lossy and lossless), etc.
RAW stores information directly obtained from the sensor of a digital camera or similar device without applying any transformations to it, and also stores camera settings. Allows you to avoid loss of information when applying various transformations to an image (loss of information occurs as a result of rounding and pixel color going beyond the permissible values). Used when shooting in difficult conditions (low lighting, inability to set white balance, etc.) for subsequent processing on a computer (usually in manual mode). Almost all semi-professional and professional digital cameras allow you to save RAW images. The file format depends on the camera model; there is no single standard.

Story

The first computers did not have separate means for working with graphics, but were already used to obtain and process images. Programming the memory of the first electronic machines, built on the basis of a matrix of lamps, it was possible to obtain patterns.

In 1961, programmer S. Russell led the project to create the first computer game with graphics. The creation of the game "Spacewar" took about 200 man-hours. The game was created on a PDP-1 machine.

In 1963, American scientist Ivan Sutherland created the Sketchpad software and hardware system, which made it possible to draw points, lines and circles on a tube with a digital pen. Basic actions with primitives were supported: moving, copying, etc. In fact, it was the first vector editor implemented on a computer. The program can also be called the first graphical interface, and it was such even before the term itself appeared.

In the mid-1960s. developments in industrial computer graphics applications appeared. Thus, under the leadership of T. Moffett and N. Taylor, Itek developed a digital electronic drawing machine. In 1964, General Motors introduced the DAC-1 computer-aided design system, developed jointly with IBM.

In 1968, a group led by N. N. Konstantinov created a computer mathematical model of cat movement. The BESM-4 machine, executing a written program for solving differential equations, drew the cartoon “Kitty,” which was a breakthrough for its time. An alphanumeric printer was used for visualization. Computer graphics experienced significant progress with the advent of the ability to store images and display them on a computer display.

Computer graphics have quietly but firmly entered our everyday lives. It has long ceased to be the lot of the elite. Every time you transfer photos from a digital camera to a computer or simply click on the “save” button to add a picture you like to your collection, you are working with computer graphics.

Is it worth spending time on theory? Knowing the basics of how image manipulation works will serve you well good service

Editing your own photos will also move from the “scientific poking method” to a completely new level. And for some, innocent fun with images on the screen gradually turned into quite profitable work.

Difference between raster and vector graphics

At the moment, vector and raster graphics are mainly used in the computer environment. They differ radically from each other in the way they encode information.

It's no secret that all data on a computer is recorded using binary code. Thus, any information, be it text, picture or sound, is encrypted in a certain way. In order to save a vector image, it is divided into elementary geometric figures, which, in turn, are described by the simplest mathematical formulas. Thus, for example, the letter “and” for a graphic editor will be described by two parallel segments of a given length, which are connected by a line at an angle of 45 degrees.

A raster image is divided according to a different principle. The computer splits the image into many dots, called pixels, and remembers the color and location of each pixel.

Advantages and disadvantages

If you are working with a vector drawing, you can theoretically enlarge it indefinitely. Moreover, this will in no way affect the quality of the image. Since the parameters are given in the form of geometric formulas, the computer simply processes them and fills all the spaces with the required colors. As a result, you have a clear image.

The disadvantages of raster graphics lie precisely in the fact that during compression (which in the vast majority of cases occurs when saving a file) the quality can significantly suffer. So-called graininess appears. However, it is raster graphics that are used in complex images. In vector drawings you can only create very simple pictures. So for now we'll focus on where raster graphics are used.

Areas of use

Raster images perfectly convey the content of scanned objects. With their help you can work with halftones and smooth color transitions. Photos taken with a digital camera also use raster images exclusively. This format also serves as an indispensable tool in the field of web design.

Raster graphics formats

Recall that image information in our case is encoded using dots. The unit of measurement in this encoding is the pixel. It is the smallest point that cannot be divided either in size or color.

The number of these points per given unit area is called resolution. In an image with higher resolution (a large number of individual dots), we will see a clear pattern and smooth color transitions. However, in the case when the resolution is small, the quality of the picture can suffer greatly (after all, the computer simply displays the number of pixels available in its memory on the screen and stretches them to the requested size).

It can be roughly compared to language. In order to convey the same information in different languages, different numbers of letters, sounds and words are required. Also, in most cases the grammatical construction will differ. And the “translators” from these “languages” in our computers are specialized programs that either “read” it or convert it into the required format.

The main difference between the formats remains the way information is stored. Let's look at the most common ones.

BMP

This is one of the pioneers. When it was developed, raster graphics were, one might say, at the very origins of their existence. The creators didn’t bother too much and programmed the BMP to memorize each pixel sequentially. In fact, this is just copying, but with some loss of color, since the BMP format only has 256 colors.

TIFF

Quite cumbersome on the scale of digital storage, but simply irreplaceable when outputting information to print. Unlike BMP, it supports information capability. Moreover, for this you can use not one, but several different algorithms. However, unless you work in the printing industry or at least some kind of publishing, you won't really need the serious power of this format.

GIF

This is a format closer to real use (for non-specialists). It is especially famous for its ability to use animation sequences. Computer graphics made in this format also allows you to create translucent images. However, you will not be able to convey smooth color transitions. The most common use of raster graphics in the GIF format can be seen in web design. It is compatible with all platforms and also compresses information quite compactly, which is an important factor in the speed of opening Internet pages.

JPEG

The most popular format. And this is well deserved. Any raster graphics editors undoubtedly support this format. It was designed with the specific goal of getting rid of the limitations imposed by GIF file compression. in this format reaches a coefficient of 100 units. This is a big indicator. However, such compression still has its drawbacks - some data loss occurs, and it is possible that the saved image will become somewhat blurry. Since this format simply discards information it considers unimportant, there is always a risk that some details will be distorted.

JPEG 2000

An improved version of an earlier version. Image information is compressed even more compactly, and there are significantly fewer losses in quality. Most often, this format is used to store photos on a computer’s hard drive and on the Internet. However, keep in mind that if you repeatedly save the same image in JPEG or JPEG 2000 formats, it will lose bits of information each time, and you will end up with a significantly distorted image compared to the original.

PNG

A significantly improved quality counterpart to the GIF format. Having retained literally all the advantages of its predecessor, it is devoid of its disadvantages. Used both for and in web page design. In addition, PNG, unlike GIF, is officially freely available.

PSD

Raster graphics in PSD format are processed exclusively in the program Adobe Photoshop. This is an internal package of this program. It supports working with layers of an edited image.

CDR

It is also an internal package for a raster graphics program. Typically, this program is used by graphic designers to create images from scratch. But the editing function is undoubtedly supported.

Raster graphics editors

And now a little about programs that work with image editing.

The most popular program among users at the moment is the Adobe Photoshop program, commonly referred to simply as “Photoshop”. This development, in fact, monopolized the work with raster images among design specialists. However, this program is paid and it does not cost that little. Therefore, developments from other companies began to appear. Some of them have already been widely used.

As for Photoshop itself, this did not affect its popularity in any way. The program is quite simple, and there is no shortage of various video courses and tutorials.

In Photoshop, you can not only make a collage of photos or add built-in effects to the image. The simplest functions of this program can be mastered very quickly, and this will open the door to unbridled flights of imagination. You can correct defects in appearance, adjust the color scheme, change the background and much, much more.

Graphics editor GIMP

As for free programs, then we can safely recommend GIMP. This graphic editor can easily supplant the popular Photoshop. It excels at all the tasks needed for raster image editing, and has some introductory features for working with vector graphics.

The GIMP program allows you to make photos more rich and vibrant, it easily removes unnecessary elements from the image and can be used for preparing professional design projects. Computer graphics created with this program look natural and fit seamlessly into the overall picture.

Graphics editor Corel DRAW

It would be wrong to ignore Corel products. In Corel DRAW, you can easily work with both raster and vector images. The capabilities of this tool are so numerous that studying the Corel DRAW program is included in the mandatory training course for graphic designers in colleges.

This program is also paid, and the arsenal of its products is replenished with enviable regularity. But, despite the wide range of possibilities that this graphic editor provides the user, its intuitive interface turns the work process into a pleasure.

Free graphic editors

And just a few more words about alternative programs for image editing. In most cases, they cope well with the needs of the average user, and take up much less space and resources on your computer. And it’s generally easier to work with them, since you won’t be overloaded with the need to choose among all sorts of functions, the purpose of which remains unclear.

If you like unusual and mostly humorous photographs, try using the Funny Photo Maker program. There you will find many original frames and fun visual effects.

For more serious work, Picasa is suitable. This editor is designed for use in computer networks. Its new features will make it even easier for you to design your pages in in social networks. And the built-in effects for editing will not disappoint even the most experienced specialist.

Another interesting program is Paint.NET. It is very similar in its functions and capabilities to Adobe Photoshop. And the tools used in Paint.NET can seriously compete with the mentioned commercial analogue.

A computer raster image is represented as a rectangular matrix, each cell of which is represented by a colored dot.

When an image is digitized, it is divided into such tiny cells that the human eye does not see them, perceiving the entire image as a whole. The grid itself was named raster map, and its unit element is called pixel.

Pixels are like the grains of a photograph, and when magnified significantly they become noticeable. A raster map is a set (array) of triplets of numbers: two coordinates of a pixel on the plane and its color.

Unlike vector images, when creating raster graphics objects, mathematical formulas are not used, therefore, to synthesize raster images, it is necessary to set the resolution and dimensions of the image.

Using raster graphics, you can reflect and convey the entire gamut of shades and subtle effects inherent in a real image. A raster image is closer to a photograph; it allows you to more accurately reproduce the main characteristics of a photograph: illumination, transparency and depth of field.

Most often, raster images are obtained by scanning photographs and other images, using a digital camera, or by “capturing” a frame from a video. Raster images can also be obtained directly in raster or vector graphics by converting vector images.

There are many raster graphics file formats, and each has its own way of encoding image information. We list the features of only the most common formats.

Format	Max. number of bits/pixel	Max. number of colors	Max. image size, pixel	Compression methods	Encoding Multiple Images
BMP		16 777 216	65535 x 65535	RLE	-
GIF			65535 x 65535	LZW	+
JPEG		16 777 216	65535 x 65535	JPEG	-
PCX		16 777 216	65535 x 65535	RLE	-
PNG		281 474 976 710 656	2,147,483,647 x 2,147,483,647	Deflation (variant LZ77)	-
TIFF		16 777 216	total 4,294,967,295	LZW, RLE and others	+

From a large number of formats graphic files Only two are currently widely used on the Internet - GIF and JPEG. Let's talk about them in more detail.

GIF format

The popular GIF format was developed by CompuServe as independent of hardware. It is designed to store compressed raster images. Several images can be stored in one file of this format. Typically this feature is used to store animated images (as a set of frames).

The GIF format allows you to record an image “through a line” (Interlaced), thanks to which, having only part of the file, you can see the entire image, but with a lower resolution. This feature is widely used on the Internet. At first you see a picture with a rough resolution, and as new data arrives, its quality improves. The main limitation of the GIF format is that a color image can contain a maximum of 256 colors. This is clearly not enough for printing.

JPEG format

JPEG file format ( Joint Photographic Experts Group - Joint Expert Group on Photography) was developed by C-Cube Microsystems as effective method Storing images with great color depth, such as those produced by scanning photographs with many subtle (and sometimes imperceptible) shades of color.

The biggest difference between JPEG and other formats is that JPEG uses lossy compression algorithm(not a lossless algorithm).

The lossless compression algorithm preserves image information so that the decompressed image exactly matches the original. Lossy compression sacrifices some image information to achieve a higher compression ratio.

The compression used in the JPEG format permanently distorts the image. This is not noticeable when simple viewing, but becomes obvious with subsequent manipulations. But the file size is 10 to 500 times smaller than BMP! If you decide to record an image in JPEG format, it is better to complete all the necessary operations before recording the file for the first time.

Comparison of GIF and JPEG

The GIF format is convenient when working with hand-drawn pictures.
The JPEG format is best used for storing photographs and images with a lot of colors.
The GIF format is used to create animations and images with a transparent background.

Vector graphics

The main logical element of vector graphics is the geometric object. The objects accepted are simple geometric shapes (so-called primitives - rectangle, circle, ellipse, line), composite shapes or shapes built from primitives, color fills, including gradients.

The advantage of vector graphics is that the shape, color and spatial position of its constituent objects can be described using mathematical formulas.

An important object in vector graphics is the spline. A spline is a curve by which one or another geometric figure is described. Modern fonts are built on splines TrueType And PostScript.

Vector graphics have many advantages. It is economical in terms of the disk space required to store images: this is due to the fact that it is not the image itself that is saved, but only some basic data, using which the program recreates the image each time. In addition, describing color characteristics does not increase the file size at all.

Vector graphics objects are easily transformed and modified, which has virtually no effect on image quality. Scaling, rotation, curvature can be reduced to a couple of three elementary transformations over vectors.

In those areas of graphics where maintaining clear and precise outlines is important, for example, in type compositions, in creating logos, etc., vector programs are indispensable.

Vector graphics can also include fragments of raster graphics: the fragment becomes the same object as all the others (albeit with significant limitations in processing).

An important advantage of vector graphics programs is the developed means of integrating images and text and a unified approach to them. Therefore, vector graphics programs are indispensable in the field of design, technical drawing, for drawing, graphic and design work.

However, on the other hand, vector graphics may seem overly rigid, “plywood”. It is really limited in purely pictorial means: it is almost impossible to create photorealistic images in vector graphics programs.

And besides, the vector principle of image description does not allow automating the input of graphic information, as a scanner does for bitmap graphics.

Recently, 3D modeling programs, also of a vector nature, have become increasingly widespread.

Featuring sophisticated rendering techniques (ray tracing, emissivity), these programs allow you to create photorealistic raster images with arbitrary resolution from vector objects with a moderate amount of effort and time.

Images in raster graphics presented as an array of numbers. The main element of the image is the dot. When displayed on a screen, this point is called pixel(from the English expression picture element – pixel). In a digital image, each raster point (pixel) is represented by a single parameter - color. This is what is meant when we consider the concept of "pixel value".

It is necessary to distinguish between technical and mathematical raster. Technical raster– an integer lattice on the plane. For example, this is how an image is realized on a TV screen or monitor. To represent a geometric image, a set of raster elements on an integer plane is used. In what follows we will use only this parameter, and we will call it raster(raster map - bitmap). Upon closer inspection, the image resembles a mosaic panel - you can see the small phosphor dots - the pixels that make up the screen image. Looking at any illustration in books and magazines, you can also notice that the image is built from dots. However, the raster dots are small enough for the human eye to perceive a collection of multi-colored dots as a single picture, and not each of them separately.

For raster graphics, the concept of resolution is key. Permission– the number of points per unit length. There are:

- original resolution;

- monitor resolution;

- print resolution.

Both drawing and sketching have their advantages and disadvantages.

The advantage of drawing programs (raster graphics) is the completely natural way of creating images. If we take the Photoshop program as an example, then, despite all its complexity, the basic visual tools underlying this program are no more complicated than an ordinary pencil. The user alternates drawing and erasing what he has drawn until he achieves what he wants, just as he did in elementary school. Raster images provide maximum realism, since every smallest fragment of the original is translated into digital form.

With all the simplicity of the basic Photoshop tools, the user can also customize them “for themselves.” This equates to an endless variety of crayons, colored pencils, spray bottles, watercolors, oil paints, and more. Moreover, the drawing can be erased, corrected, etc. at any time.

Another advantage seems to be simplicity and, as a consequence, the technical feasibility of automating the input (digitization) of visual information. This simplicity is based on forced sampling into elements and digitizing them in accordance with any predefined quantization tables. There is a developed system of external devices for inputting photographs, slides, drawings, watercolors and other fine originals, these include scanners, video cameras, and digital cameras. These external devices are constantly being improved, providing the ability to increasingly adequately convert images on physical media (paper, film, etc.) into digital form.

Raster graphics have software independence. This advantage, to a certain extent, is also a consequence of the simple principle underlying pixel art. The nature of the information (a collection of numbers organized in a two-dimensional matrix) that is required to store a pixel image allows the creation of standard formats. These formats are “understood” by almost all programs that work with images: pixel and vector graphics editors, layout programs, browsers and even operating systems.

Disadvantage of drawing programs - in limited resolution.Because the bitmap consists of a fixed number of pixels, the resolution of the image depends on the size at which the image is printed. In a small printout, the pixels are small and the resolution is high; Larger printouts enlarge pixels and reduce resolution. An image on a 15-inch screen (800x600 pixels) will only produce a continuous color change in a printout the size of half a postage stamp. If you print it “full-length” on A4 paper, individual pixels will be clearly visible, forming jagged lines in place of smooth lines. The only way to deal with this situation is to increase the number of pixels in the image, which, however, entails a sharp increase in the size of the image file. Since the image consists of dots, enlarging the image only leads to the fact that these dots become larger. No additional detail when zoomed in bitmap cannot be considered. The very increase in raster dots visually distorts the illustration and makes it rough. This effect is called pixelation.

Thus, The quality of raster images depends on their size. As a consequence of the fact that they consist of pixels of a fixed size, free scaling without loss of quality is not applicable to them. This feature, as well as the structure of raster images itself, makes their editing and processing somewhat difficult. You can improve image quality by increasing the resolution, but this leads to a significant increase in file size. Therefore, one of the main disadvantages of raster graphics is large file sizes.

V= L W R 2 D

Where, L is the image length in inches, W is the image width in inches, R is the resolution in ppi, D is the color depth.

A serious flaw will surface when trying to rotate an image slightly, such as one with clear thin vertical lines, by a small angle. It is immediately apparent that clear lines turn into “steps”. This means that for any transformations (rotations, scaling, tilting, etc.) in the bitmap it is impossible to do without distortion(this is dictated by the discrete nature of the image). You could even say that bitmap graphics are easier to deform than to transform.

When editing bitmaps color changes a certain set of pixels. The change in color results in a change in the shape of the depicted objects.

A serious disadvantage is hardware dependency Raster graphics.

If we take a general look at external devices, almost all of them visualize images using a bitmap. Any image is built from a combination of some elements (for example, screen pixels, ink drops, toner dots), so each of these devices is characterized by its own resolution. And this parameter plays a significant role when printing an image, since a discrete image grid is superimposed on the discrete grid of the device. And this “meeting” is not always favorable for the final result. In particular, it is this “event” that causes moire (moire will be discussed in more detail in the section Printing images).

On the other hand, the image sampling grid is formed, unfortunately, at the very beginning of the process, and subsequent changes to the sampling grid (resolution), as we found out earlier, do not provide any improvement at all.

Raster graphics are images made up of pixels - small colored squares arranged in a rectangular grid. Pixel is the smallest unit digital image. The quality of a raster image directly depends on the number of pixels it consists of - the more pixels, the more detail can be displayed. Enlarging a raster image by simply increasing the scale will not work - it is impossible to increase the number of pixels, I think many were convinced of this when they tried to see small details in a small digital photograph by zooming it in on the screen; As a result of this action, it was not possible to see anything other than increasing squares (that’s exactly what they are - pixels). This trick is only possible for CIA agents in Hollywood films, when they use enlarged images from an external surveillance camera to recognize car license plates. If you are not an employee of this structure and do not own such magical equipment, nothing will work out for you.

A raster image has several characteristics. For a photo stocker, the most important things are: resolution, size and color model. Sometimes the size is also called resolution and therefore confusion occurs; to prevent this from happening, you need to clearly understand what we are talking about and “look in context” - the size is measured in MP (megapixels), and resolution - dpi or ppi.

Permission is the number of pixels per inch (ppi - pixel per inch) to describe the display on the screen or the number of dots per inch (dpi - dot per inch) to describe the printing of images. There are several well-established rules: for publishing an image on the Internet, a resolution of 72ppi is used, and for printing - 300dpi(ppi). Microstock image requirements are 300dpi, since many works are purchased specifically for printing.

Size- the total number of pixels in an image, usually measured in MP (megapixels), this is simply the result of multiplying the number of pixels in height by the number of pixels in width of the image. That is, if the photo size is 2000x1500, then its size will be 2000*1500=3,000,000 pixels or 3MP. To send to photo banks, the image size should not be less than 4 megapixels, and in the case of illustrations - no more than 25 megapixels.

Color model- a characteristic of an image that describes its representation based on color channels. I know of 4 color models - RGB (red, green and blue channels), CMYK (cyan, magenta, yellow and black), LAB (lightness, red-green and blue-yellow) and Grayscale (grayscale). All microstocks accept raster graphics in the RGB color model.

Advantages of raster graphics:

Ability to reproduce images of any complexity level. The amount of detail reproduced in an image largely depends on the number of pixels.
Accurate reproduction of color transitions.
Availability of many programs for displaying and editing raster graphics. The vast majority of programs support the same raster graphics file formats. Raster representation is perhaps the “oldest” way of storing digital images.

Disadvantages of raster graphics

Large file size. In fact, for each pixel it is necessary to store information about its coordinates and color.
Impossibility of scaling (in particular, enlarging) an image without losing quality.

Raster graphics formats

Despite the apparent simplicity of the presentation of raster graphics, there are “wagons and small carts” in their formats! And their number continues to change - some formats are becoming obsolete, others are just beginning to be developed. Describing everything would be long and not interesting; I will only describe those that, in my opinion, may be of interest to designers and photostockers.

PNG(Portable Network Graphics) is another raster graphics format that supports transparency, not only regular transparency like GIF, but also translucency - a smooth transition of color into a transparent area. The purpose of creating PNG was precisely to replace GIF, since CompuServe, the developer of the GIF format, patented the compression algorithm used to create GIF images for 10 years in 1995, which made it impossible to use this format for free in commercial projects.

Advantages of PNG:

The ability to create a full-color image with color transitions and halftones.
Save graphic information using a lossless compression algorithm.
The ability to use alpha channels, that is, simply put, transparency and, moreover, translucency, which allows you to create smooth color transitions into a transparent area.

PNG, in my opinion, has only 2 disadvantages:

Inability to create an animated image
Ambiguous “understanding” of the transparency of the PNG format by Internet browsers. Some browsers, mostly older versions, refuse to display transparent areas of a PNG image and paint them gray. But this drawback, I think, will soon cease to be relevant.

TIFF(Tagged Image File Format) - format for storing images High Quality, supports any of the existing color models, provides a wide range of color depth changes, supports working with layers. Storing information in the TIFF format is possible both with and without losses. Cameras that do not support RAW format can sometimes take photos in TIFF format.

On photo banks that have the ability to upload additional formats to the main image in JPEG format (Dreamstime.com, iStock.com), you can upload TIFF as an additional one.

The disadvantage of the format is the large weight of the file, much larger than a RAW file of the same quality - each image in TIFF weighs from 8 to 20 MB.

RAW(translated from English “raw” - raw)

The RAW format appeared thanks to digital cameras. RAW is essentially a “print” that remains on the camera matrix at the time of shooting, or rather as many as 3 prints - in red, green and blue colors. In addition to these prints, the RAW file also stores some other data, which in this case is more of a reference nature, dictating to the RAW converter with what intensity to display each of the color channels for different pixels on the screen - this is white balance, color space, etc. . Changing these parameters will not affect the original information in any way; you can change them painlessly and return to the original view at any time. It will be much more problematic to work with another raster format obtained as a result of export. Extensions for files in RAW format can be different (.cr2, .crw, .nef, etc.) depending on the brand of the camera - each camera manufacturer has its own way of storing information. To edit RAW files and convert them to other raster formats, camera manufacturers supply their own software, and the Canon RAW converter will only read RAW files shot with Canon cameras (.cr2,.crw) and will not be able to read the RAW file shot Nikon camera (.nef). There are third-party RAW converters that work with most RAW files. In general, the lack of a unified standard creates certain inconveniences when working with this format.

The disadvantages of the format are the large file size (although not as large as TIFF) and the lack of a uniform standard for generating RAW files for all manufacturers of photographic equipment.

RAW, like TIFF, can be sent to photo banks as an “additional” image format - the availability of the source can influence the designer’s decision to purchase the image.

JPEG(Joint Photographic Experts Group - the name of the developer) is the most common raster graphics format (at least on the Internet). JPEG is an example of the use of “lossy” or, in other words, “distorting compression” compression algorithms; it is most suitable for storing paintings, photographs and other realistic images with smooth color transitions, but practically unsuitable for drawings and diagrams, that is, for images with sharp transitions - the compression algorithm will form noticeable artifacts in places of sharp contrast.

It is not recommended to store intermediate versions of work in this format - each “re-saving” will lead to irreversible loss of part of the information. The compression algorithm used in this format (lossy compress) is based on “averaging” the color of adjacent pixels.

JPEG does not support working with alpha channels, that is, it cannot contain transparent pixels, but it allows you to save a clipping path in the file, which in the case of working with photo banks must be noted in the description, the presence of a clipping path (if, of course, you have made it and know what is it) - this is important information for the buyer of the image.

The JPEG format is also the main format in which photo banks accept raster images (photos and illustrations) for sale. The final version of the file sent to the microstock must be saved in the RGB color model, with a resolution of 300dpi and, of course, in 100% quality. You can also enter IPTC information (title, description, keywords) into the file - the JPEG format allows you to do this and this will significantly save you time when sending images to several photo banks.

In addition to common raster graphics formats (GIF, JPEG, TIFF, etc.), which are “readable” by everyone graphic editors and image viewers, there are “native” formats of almost every editor that can only be opened by the program in which they were made, for example, the .PSD format of Adobe Photoshop. When processing photographs, raster illustrations and design development, intermediate versions should be saved in such formats and only the final versions should be translated into JPEG. This is necessary so that you can save the results of your work without losing information and make changes to the image or project at any time.