Photo size 15 by 20 pixels. Image resolution and print quality. B) The picture is stretched so that it would fill the entire sheet of photographic paper, and what is not included in the photographic paper is cut in automatic mode - this is called

Let's get acquainted with some of the terms that are used in the world of digital photography.

Linear photo size is the width and height of the printed photo in millimeters. The linear size of a photograph can be obtained by measuring it with a regular ruler. For example, the linear size of a 9x13 photo is 89x127 mm.

Pixels are the points that make up the image. Just as a mosaic is made up of pieces, a digital photograph is made up of pixels. The more pixels, the finer details can be seen in the image.

Size in pixels is the width and height in pixels of the digital image. For example, digital cameras take pictures of standard sizes 640x480, 1600x1200, etc., and the number of pixels displayed on a computer monitor is 800x600, 1024x768, 1280x1024.

Permission is a number that connects the size of the image in pixels and the linear dimensions of the print. It is measured in the number of pixels (dots) per inch (1 inch = 25.4 mm) - dpi (dots per inch). Recommended resolution for high quality photos is 300 dpi. Practice shows that the minimum acceptable resolution for printing photographs is 150 dpi.

In most cases, you print photos of a standard format 9x13, 10x15, 13x18, 15x20, etc. Strictly defined linear dimensions correspond to each format. For each format, you can calculate the recommended sizes of the original image in pixels, so that the resulting print has a resolution of 300 dpi or more.

For example, the linear dimensions of the format 9x13 - 89x127 mm. Multiply the height of the photo (87 mm) by the resolution (300 dpi) and divide by the number of millimeters in one inch (25.4 mm), the result will be the number of pixels in the original image in height

89 * 300 / 25.4 = 1027 pixels.

Likewise for the width

127 * 300 / 25.4 = 1500 pixels.

Thus, for any image larger than 1027x1500 pixels, when printed at 9x13, the resolution will be greater than 300 dpi. In practice, it often happens that a photograph with a resolution of 150 dpi looks no worse than the exact same one, but with a resolution of 300 dpi, it depends on what is shown in the photograph and from what distance it will be viewed.

When placing an order via the Internet, the system automatically determines which formats are recommended for printing the uploaded photo. If you have chosen a format other than the recommended, then the corresponding message is displayed, while the administration is not responsible for the poor quality of the printed photograph.

Table of standard sizes and corresponding linear dimensions.

Photo format	Linear dimensions for digital printing	Photo size in pixels (for 300 dpi printing)

For a novice user, Photoshop will seem like a magical tool that with mysterious ease can change any photo beyond recognition. But how!? Tell! How he does it? What is the mechanism working? What happens inside a photograph that it changes as you like, as if it were a chameleon? Nothing complicated, you just need to know what digital photography consists of and what rules apply to it, then everything will fall into place.

Namely, with this kind of graphics, Photoshop works, it consists of tiny elements - pixels, like any object of the smallest particles - atoms.

Pixels Are tiny square-shaped elements that contain information about color, brightness and transparency. The term comes from crossing two English words - picture and element (element).

A digital image file consists of vertical and horizontal rows of pixels that fill its height and width, respectively. The more pixels an image contains, the more detail it can display. They are imperceptible to the human eye, because they are negligible. To see them, you will have to greatly enlarge the image:

Pay attention to . The visible part of the image is marked with a red frame. I zoomed in to 1200% on the area where the panda's nose and mouth are depicted. As you can see, the image consists of a set of colored squares. When enlarged, it looks like a patchwork quilt made of square pieces.

Taking a closer look, you can understand the basic principles of image construction:

1. Pixels are square in shape and are arranged in the image in the form of a grid (remember a notebook sheet in a box).

2. Squares are always strictly of one definite color, they cannot even be a gradient. Even if it seems to you that some square is shimmering with color, then this is nothing more than an optical illusion. Increase this area even more and you will be convinced of this.

3. A smooth transition between colors occurs due to the gradually changing tones of adjacent pixels. Even the line of contact of contrasting colors can contain more than a dozen tones.

Image Resolution

Image resolution is inextricably linked to pixels.

Digital photography resolution is recorded as follows: 1920 × 1280. Such a record means that the image is 1920 pixels wide and 1280 pixels high, that is, these numbers are nothing more than the number of those smallest squares in one row and column.

by the way, if you multiply these two numbers - 1920 × 1280 (in my example, you get 2,457,600 pixels), then we get the total number "Scraps" that make up a particular image. This number can be reduced and written as 2.5 Megapixels (MP)... You came across such abbreviations when you got acquainted with the characteristics of a digital camera or, for example, a camera in a smartphone. Technology manufacturers indicate the limit that their product is capable of. This means that the higher the number of MPs, the higher the resolution of future images can be.

So, the higher the resolution, the smaller the pixels, which means that the quality and detail of the image increases. But a photo with a higher resolution will weigh more - such is the price of quality. Since each pixel stores certain information, with an increase in their number, more computer memory is required, which means that their weight grows. For example, the photo with bears at the top of the article with a resolution of 655 × 510 weighs 58 KB, and a photo with a resolution of 5184 × 3456 will take 6 MB.

Pixel dimensions and printing

It is important to distinguish between situations when we are talking about pixel sizes and their effect on photo quality.

Looking at the images on the monitor screen, we see that the pixel dimensions are always the same. The computer resolution size is considered 72 dpi.

Note

Please note, when you create a new document in Photoshop, the program offers you exactly this value by default:

When viewing large photographs on a computer, for example, 5184 × 3456, you can feel how detailed it is, there is no grain and no defects, it is bright and clear. But believe me, such a photo is again 72 dpi. Let's open the properties of the image for the sake of interest:

A large photo will look great on a computer thanks to the scale. What is your screen resolution? Obviously not 5184 × 3456, but less. So the computer must reduce such a photo so that it fits entirely on the computer screen. The pixels are compressed and reduced in size, which means that here it is a cool image quality. If you were viewing such a photo at its original size, you could easily see the blurring and tarnishing of the image, as well as the sharp edges of contrasting details.

Pixel sizes are most often remembered when it comes to printing a photo. Here 72 points may not be enough.

As an example, I created a document with dimensions of 655 × 400 pixels with a resolution of 72 pixels. Look in the graph print size:

Photoshop has calculated that a 655x400 72-dot image can be printed on 9.097x5.556 inches paper (23.11x14.11 in centimeters)

655 pixels wide divided by 72 pixels per inch = 9.097 inches wide
400 pixels divided by 72 pixels per inch = 5.556 inches high

It would seem, “Wow! What a big sheet you can print on! " But in fact, the photo will be something like this:

Blurry photo, no sharpness and clarity.

Printers are considered high-resolution devices, so in order for photos to be printed beautifully, you either need to print photos at an initially large size, like mine is 5184 × 3456, or change the number of dots per inch in the range from 200 to 300.

Again, I will take the same 655 × 400 image, but change the number of points to 200, this is what Photoshop writes:

The size of the print has been reduced by almost three times. Now our image is printed at 200 pixels per inch of paper.

What happens is that the image will be small, it will hardly fit into a standard 10 by 15 photograph, but it will be of high quality, clear and detailed.

It turns out that there is a certain minimum resolution size for printing photographs. If the picture is initially small in size, as I had, then there is even nothing to think about good print quality.

What size should the image be in order to print it beautifully?

Let's say you came from the Crimea from a vacation, or took 100,500 photographs of a child and, of course, you want to print something into a photo album (example 1), and one of the most remarkable to make in the form of a picture on the wall (example 2)... Let's figure out what size such photos should be and whether modern cameras can achieve this.

Example 1

So, as a rule, there are photos of the size 10 × 15 cm(in inches this is 3.937 × 5.906). Now we will find out what should be the minimum photo size for everything to be beautifully printed. For calculations, we take a resolution of 200 dpi.

200 pixels per inch x 3.937 inches wide = 787 pixels
200 pixels per inch x 5.906 inches high = 1181 pixels.

That is a photograph 10 × 15 cm = 787 × 1181 pixels, minimum (!)

And having found out the total number of pixels in this resolution (787 × 1181 = 929447 pixels), rounded to the nearest million, we get 1MP (megapixel). I already wrote that the number of megapixels is the most important characteristic of modern cameras. The average number of MP in cameras and smartphones is about 8 MP.

This means that the current technology will easily make it possible to take photographs suitable immediately for printing pictures in 10 × 15 cm.

Example 2

Now let's analyze the case when you have chosen a photo and want to hang it on the wall in a frame measuring, say, 30 × 40 cm (I took the frame size from the IKEA store catalog), I will immediately translate it into inches: 11.811 × 15.748. For this photo size, I would take the maximum resolution size: 300 dpi, this is already considered a professional and highest quality print (just what you need for a large picture in a frame). And now the calculations:

300 pixels per inch x 11.811 inches wide = 3543 pixels
300 pixels per inch x 15.748 inches high = 4724 pixels.

Thus, your photo must be at least 3543 × 4724 pixels. Multiply the values and get 16.737.132 pixels or 17 MP!

Thus, to print a framed photo, you need a powerful camera. This range is already being considered. And this is an expensive and serious type of equipment.

In general, and in general, you should now at least a little understand how the Photoshop program works and how all these photo editing frauds turn out. Having learned about pixels, their properties and capabilities, this process should no longer seem like magic.

If you noticed an error in the text, select it and press Ctrl + Enter. Thanks!

Many of us love to photograph. The variety and affordability of digital cameras make photography a popular pleasure to capture the vivid, colorful moments of our lives. At the same time, the high quality of the obtained photographs does not at all guarantee the same quality when printing digital photographs on standard roll photo paper. In this material I will tell you what are the sizes of photos for printing, I will give tables of available formats, and I will also give a number of examples that allow you to clearly understand the features of different sizes of photos.

Digital photographer's thesaurus

To understand what are the sizes of photographs for printing and what are their specifics, we need, first of all, to understand the basic concepts necessary to understand the process of digital printing.

Linear photo size- dimensions of the photograph in millimeters (width-height).

Photo parameters in pixels- the dimensions of your photo, expressed in the number of pixels (width-height).

Pixel- the smallest element of the image, usually a point of a rectangular or circular shape, and of a certain color. An image consists of hundreds or thousands of such pixels, which are counted both horizontally (width) and vertically (height). For example, an image size of 1181x1772 (usually corresponding to a standard photo size of 10x15) is 1181 pixels wide and 1772 pixels high.

Moreover, the more such dots-pixels in your image, the usually it is of better quality, with better detail and rendering of objects.

Aspect ratio- the aspect ratio of the photo (for example, 1: 1, 2: 3, 3: 4, and so on). The parameter shows how much one side is shorter or longer than the other.

Bitmap (raster)- an image consisting of such pixels.

DPI- (abbreviation for "dots per inch" - dots per inch) - a parameter used to characterize the resolution of printing photos, that is, the number of dots per inch (inch is 2.54 cm). The basic printing standard is 150 dpi, the optimal one is 300 dpi. Accordingly, the higher the DPI, the higher the print quality of the existing digital photo.

Standard (format) photo- This is a stereotyped aspect ratio of a photograph, which is important to adhere to in order to obtain the final image on paper.

Why it's important to consider standard photo sizes

In the vast majority of cases, your digital photographs will be printed on photo paper that has standard sizes. If the proportions of digital photographs and the selected sizes of photographic paper do not match, the photographs may come out stretched, not clear, lose the quality of the image, and have other undesirable consequences for you.

Therefore, it is important to measure the standard print sizes of your photos and the pixel sizes you have of your digital photos in order to choose the optimal print format.

Popular photo sizes for printing with a table of formats

The generally accepted standard for a photo is 10 by 15 cm. In this case, the size of a commensurate digital photo is usually slightly larger (for example, 10.2 by 15.2 cm), and the size in pixels of this photo will be 1205 by 1795 pixels.

Other formats are shown in the table below:

If you plan to work with large-format printing, then it has fairly broad requirements for a digital image:

If you know the dpi parameter and the number of pixels of your photo, then using the formula below, you can calculate the required dimensions of the sides of your photo:

In this formula:

x is the required size of one side of the photo in centimeters;
r - photo side resolution in pixels;
d - 2.54 cm (standard inch size);
dpi - usually 300 (less often - 150).
For example, let's say the width of the image is 1772 pixels and dpi = 300.
Then 1772 * 2.54 / 300 = 15.00 cm in print width.

Popular photo formats

In addition to the classic 10 by 15 (A6 format) I have already mentioned, there are other popular photo sizes for printing. Among them, I would highlight the following:

Conclusion

This article showed the standard photo sizes for printing, popular photo formats, as well as a convenient formula for calculating the optimal sizes of the sides of a photo. I recommend sticking to the formats I listed, this guarantees the quality of the printed photos, and therefore the visual pleasure of viewing them.

Hey!!!
In the 20th century, photographers did not have any questions about the format of the picture they were creating. Then it was possible to develop a photograph of any size. Now there are several formats that are most popular. This is explained by the prevalence of typical photo albums, in which pictures of a non-standard format do not look very attractive.
What are the digital photo sizes?

An ordinary picture printed on photo paper has only physical dimensions. Digital photo has many more different properties. In theory, almost any image can be printed. But if this process occurs at a pixel density of less than 300 dpi, then some artifacts will appear on the printed photo. Therefore, there are some limitations, which will be discussed below.
Photo dimensions in pixels

The most important parameter is the size (resolution) of the digital image. Computer programs display the dimensions of photographs in pixels. To print a standard photo, a resolution of at least 1795 x 1205 pixels is required. A snapshot of this size can now be obtained by any digital camera. Even in mobile phones, it is already very rare to find cameras that cannot save photos in this resolution.
Photo dimensions in cm (centimeters)

The standard size is one that has a physical size of 10 x 15 cm. For printing commemorative pictures, the larger size is usually selected. Standard photo sizes also include 15 x 20 cm, 20 x 30 cm and 30 x 45 cm. High resolution images are required to print these images. Usually, for shooting in this case, a compact, system or SLR camera is used.

Aspect ratio
An equally important parameter is the aspect ratio. This property shows how much one side is longer than the other. The standard is an aspect ratio of 3: 2. The majority of matrices installed in modern cameras have the same parameter. Sometimes other ratios are provided in the camera menu. When you select them, a banal cropping of the edges of the image occurs. In this case, the resolution is reduced to one or another value.
It is not uncommon for photographers to choose an aspect ratio of 16: 9. It is called widescreen. Now many monitors and TVs have the same parameter. On them, such pictures are displayed in full screen. But the size of the photos for printing is also changing. The width of the printed image must be increased. If you choose a standard print size, you will have to crop a fairly decent part of the image.
Photo paper

The emergence of new standards is dictated by the manufacturers of photographic paper. No photo lab will print an unusual size photo for free, as this will require cutting the finished photo. And this already applies to additional services.

Small photo sizes

Several popular formats have been mentioned above. And in the table below you will find more accurate information about the sizes of photos. But this is not the most complete list. Recently, people regularly print pictures on A4 size photo sheets. For such photographs, the corresponding frames have been produced for a long time. Also, their production can be ordered in the baguette workshops.
Miniatures are rarely printed now. The size of a small photo can be 9 x 13 cm. If you need a photo in your wallet, you will have to print it yourself on a printer or make a custom order in a photo studio. For photograph sizes, cm is not always used as the primary unit of measurement. Photos for documents (driver's license, passport, etc.) are measured in millimeters, since in this case, greater accuracy is important.
Large format printing: photo sizes

Recently, large format printing has gained great popularity. This is the name of the service for printing large-sized images with an aspect ratio of 3: 2 or any other. Typically, this service is required to print banners with vector graphics for advertising or congratulatory purposes.

Photo sizes rarely allow printing in such large formats. From the table above, you can see that a 4000 x 6000 pixel frame would be required to produce a high quality 40 x 60 cm print. Such a photo can only be provided by cameras with a 24-megapixel matrix.
Conclusion
It is advisable to have the above tables always at hand. With their help, you can quickly find out to what values you can reduce the size of a photo if necessary.

I propose to consider what kind of animals they are - JPG and RAW photo formats, what they affect and when you should pay attention to them. What is the photo size and file weight, how they are measured and what they depend on.

Almost all photo cameras can save photos in JPG format (even cameras of phones and tablets). All DSLRs and non-DSLRs, as well as advanced compacts, in addition to JPG, have at least RAW and RAW +, and sometimes TIFF.

To understand the formats, first you need to agree on what is meant by the "size" of the photo and the "weight" of the file (photo). I propose to consider these concepts on more tangible objects ... for example, on goodies.

1 | What is a pixel:

The size of objects is measured in meters, the size of a photo is in pixels (px).

If you measure the size of this vase with berries, then it will be about 10 centimeters in height and that way 13 centimeters in width ... approximately. That is, we are used to measuring objects in centimeters (meters, kilometers, and so on). If we talk about the photo of the same vase, then the original size of the photo is 7360 pixels (px) wide by 4912 pixels (px) high. This is the maximum photo size my Nikon camera is capable of. To post this photo on the site, the photo size has been reduced to 1200px by 798px (why, I'll tell you a little later).

What is a Pixel? Photos taken with digital cameras or digitized on a scanner are a combination of tiny colored squares - pixels... If you zoomed in any photo, you will see these pixels. The more such pixels in the photo, the more detailed the picture.

A fragment of a photo enlarged a thousand times - squares of pixels are visible.

2 | Can pixels be converted to centimeters:

This is exactly what happens when you need to print photos on paper. Here you need one more indicator - the pixel density (resolution) that the printer (or other machine for printing photos) can print. The printing standard for photographs is 300 dpi (dpi is the number of dots per inch). For example, photos with a resolution of 300 dpi are used for printing in beautiful glossy magazines.

So that you don't rack your brains over dividing the photo size by resolution and convert inches to centimeters, in any program for viewing and editing photos (for example, in Photoshop) there is a function for viewing the photo image size in centimeters. You will need it in order to understand what is the maximum size of a photo in good quality (with a resolution of 300 dpi), you can print on paper or other material media.

For example, this photo with tropical Frangispani flowers can be printed in 61 cm by 32 cm.

Photo size in pixels and centimeters in Photoshop

To find out the size of the photo in pixels and centimeters in Photoshop, you need to press the key combination Alt + Ctrl + I or go to the Image menu (Image) Image size (Image size).

Let's go back to the reality of digital photos - to pixels and photo sizes in pixels. What happens if you reduce the number of pixels in a photo? The answer is that the quality of the photo will deteriorate. For example, I took a photo of the same vase with berries that at the beginning of the article and reduced the size of the photo to 150 pixels wide. With this reduction, the program destroys some of the pixels. The photo has become miniature:

Now let's try to "stretch" the photo to the full page:

The stretched picture looks cloudy and indistinct

As you can see, the detail is not the same, since some of the pixels (and with them the details) are missing.

Of course, if you use this thumbnail as a small icon or a small image in a Power Point presentation, it will look quite normal, but it is clearly not suitable for printing in a magazine on half a page.

3 | What size of the photo (how many pixels) is optimal:

If you plan to print a photo someday, then save photos in the highest possible resolution, which only your camera will allow (carefully read the instructions for your camera to properly adjust the photo size).

In some cases, you need to reduce the size of your photos. As I wrote above, for the site I reduce the photo size to 1200 pixels on the long side. If you upload a photo in full size, the pages of the site will take a very long time to load, and many visitors may not like this (not to mention the search engines Google and Yandex).

The size of photos is measured in pixels (px). The number of pixels determines the size of the photo on the screens of monitors, and what size you can print the photo.

4 | File size or "photo weight":

Now let's deal with the "photo weight". It just so happened historically that there is a lot of confusion on this issue and the file size is often referred to as "photo weight", which is more convenient than correct. File sizes are measured in megabytes (MB) or kilobytes (KB). And here it is worth remembering that, unlike kilograms, where 1 kg = 1000gr, 1 megabyte = 1024 kilobytes.

How it looks in practice: let's imagine a situation that your camera has a memory card with 64GB (gigabytes) written on it. If you look at how many bytes there are (on the computer, right-click on "properties"), it turns out that on this memory card there are 63567953920 bytes and this is equal to 59.2 GB. How large the files your camera creates depends on how many photos will fit on this memory card. For example, I have 830 files with photos in RAW format (read about formats below).

What determines the file size:

First, the size of the photo (what is measured by pixels): the file with the first photo of berries (photo size 7360x4912 px) is 5.2 MB, and it, reduced to 150 px, will "weigh" 75.7 KB (in 69 times less).
Secondly, from the format (JPG, TIFF, RAW), which is described below.
Thirdly, the file size (or "photo weight") depends on the amount of details: the more there are, the "heavier" the photo (which is most relevant for the JPG format).

More details - more weight

For example, here in this photo with monkeys from Sri Lanka there are many small clear (in the language of photographers, "sharp") details and the file size with this photo is 19.7MB, which is significantly larger than berries in a vase on a white background (5.2MB).

If you ask what size photo can I print from a photo that weighs 2MB. Nobody can answer you until they know the number of pixels. And it is better, of course, to look at the photo as well, since some craftsmen like to get a photo from the depths of the Internet, increase the number of pixels programmatically, and then want to print it on the cover of a magazine. It turns out as in the example above with a stretched photograph of a vase with a width of 150 px.

File size (often referred to as "photo weight") is measured in megabytes (MB) or kilobytes (KB) and depends on the format, pixel size and detail of the photo.

5 | Photo formats:

And, finally, we come to the question of image formats and the type of file compression, which also determines the size of the file with the photo.

Almost all photo cameras can save photos in JPG format(even cameras on phones and tablets). It is the most common image format and is "understood" by all computers and image viewers. In JPG format, photos can be uploaded to social networks, posted on a blog, added to Word files, Power Point, and so on. JPG can be processed in Photoshop, Lightroom and other image editing programs.

From my practice: if I want to take a photo for a social network and quickly upload it, then I either take a photo on my phone or put the jpg file format in my camera.

One thing to remember about the jpg format is that it is a compressed format and has compression ratios. The higher the compression ratio, the smaller the file size due to the reduction in detail and quality of the photo. Therefore, multiple editing and re-saving (re-compression) of the same photos in jpg format is not recommended.

When saving a file in jpg format, the compression level is selected (example from Photoshop).

In all DSLRs and without DSLRs, as well as in advanced compacts, in addition to JPG, there is at least RAW, and often also TIFF.

A bit of theory:

Tiff(English Tagged Image File Format) is a storage format for raster graphic images (including photos). TIFF has become a popular format for storing deep color images. It is used in the printing industry, widely supported by graphics applications.
RAW(English raw - raw, unprocessed) - a digital photo format containing raw data received from a photomatrix (the thing that replaced film in digital cameras).

Personally, I never take pictures in TIFF format. I can't even think of why I need this, if there is RAW. I can use uncompressed TIFF to save photos that I still plan to finalize in Photoshop.

6 | Advantages and Disadvantages of RAW Format:

I almost always have a RAW format in my camera, since I'm going to process (edit) a photo in Lightroom or Photoshop. RAW has a number of significant disadvantages:

There is no way to view files without conversion. That is, to view photos in RAW format, you need a special program that supports this image format.
Larger file size than when saved in JPEG (from my Nikon D800 camera, the file size with a photo in RAW format is 74-77 MB). This means that fewer photos will fit on a flash drive.
RAW cannot be uploaded to social networks, blog, and sometimes even sent by mail. First, you need to convert RAW in a RAW converter (for example, Adobe Camera Raw) that supports the file type from your camera model.

Why do professional photographers often prefer RAW over JPG? Because RAW:

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gives more options for image correction: white balance, contrast, saturation, brightness and noise level,
allow you to more correct images without the appearance of defects,
allows fine correction of lens imperfections (vignetting, chromatic aberration).

So, if you plan to process your photos in the most thorough way in Photoshop or Lightroom, subtly feeling the "artifacts" and midtones, "overexposures" and "dips" in the shadows, then shoot in RAW. Just remember that in order to get a good result, you need to understand the settings and operation of RAW converters. Think if you need this headache? Maybe you should shoot in JPG and spend more time relaxing and not your computer?