Maximum photo resolution. Relationship between pixels, centimeters and DPI
Welcome to my blog again. I'm in touch with you, Timur Mustaev. It is possible that everyone had to deal with such a situation: you took a picture, on the screen the picture looked clear and of high quality.
Then you went to the salon and printed it out, and it looked completely different from the one on the monitor screen and had a lot of digital noise. What is the problem? Today I will talk in more detail about this problem and what are the photo formats. Let's start studying.
Basic terms for understanding the topic
Pixels - small square dots, colored in a certain light, which make up a single whole - an image.
When you look at a photograph, the eye does not notice the specific dots of the raster, since they are very small and their number can reach tens of thousands, they merge to form one picture. Only when magnified can you see them.
There is a feature: the higher the number of raster dots, the more details are drawn and the photograph is better.
Linear size is the width and height of the printed image, expressed in millimeters. They can be recognized using a regular ruler. For example, the linear size of a picture with parameters 10*15 cm is 102*152 mm.
Parameters in pixels are data about the width and height of the digital image.
There is one feature. Digital cameras take pictures of the same sizes: 640 * 480, 1600 * 1200, and on the monitor we see 800 * 600, 1024 * 768, 1280 * 1024. That is a significant discrepancy.
Consider examples. If the picture has a size of 450×300 pixels, then the picture will be rotated under the album, that is, it will be placed horizontally. What does it depend on? The width of the image is greater than the height.
If we take the size of the picture 300 * 450, then it will be located in portrait orientation, that is, vertically. Why so? The width is smaller than the height.
Resolution is a number that relates values in millimeters and pixels, measured in dpi(from the English "dots per inch" - the number of dots per inch).
Experts advise setting a resolution of 300 dpi, designed to obtain high-quality photographs. The minimum resolution is 150 dpi.
The higher the score, the better the photo quality.
But, it is worth noting that if you make a photograph larger than the original, that is, “stretch the dots”, then the quality drops.
Resolution may vary depending on different camera models. What is the secret? Manufacturers of photographic equipment indicate an inaccurate number of megapixels, for example, 12 MP. In fact, it may turn out to be 12.3 or 12.5 MP. But the print quality will not deteriorate from this fact.
Standard sizes
What are the photo formats? Let's find out.
- The most popular print size is 10*15 cm. It is used to form a family archive.
- The next one is 15*20 cm or A5.
- A4, 20 * 30 cm or 21 * 29.7 cm. Used to decorate walls with photographs. Since A4 is the size of office paper for printing, printing is not difficult, since printers are mainly designed for A4 production.
- 30*40 cm is a complex format. It has two other names: A3 or A3 +. Why complex? Because there is confusion. A3 size has parameters 297*420 mm, but you cannot pick up such photo frames, they are not on sale. The closest photo frame to this photo is 30*40 cm. Be careful when ordering. Photo frames are made with glass.
Custom sizes
Often we have to order a photo not of a standard size, but of a unique one - non-standard.
- 13 * 18 cm. It is used extremely rarely. Printing is difficult.
- 40 * 50 cm or 30 * 40 cm. Pictures with these parameters will help decorate the interior, since they are quite large. Therefore, the quality must be high.
How to calculate dimensions for high resolution
Let's take a closer look at a photo with parameters of 10 * 15 cm.
- The linear values of these parameters (usually indicated in special tables) are 102 * 152 mm.
- Multiply the width of the image (102 mm) by the resolution we want to achieve, in our case it is 300 dpi.
- Divide the result of the last step by the number of mm in one inch - 25.4.
- Let's get the number of raster dots of the original image in width 102*300/25.4 =1205.
We will carry out the same algorithm for the height.
152*300/25,4 = 1795.
So, we conclude that for any photograph, the size of which is greater than 1205 * 1795 pixels, when printed on a 10 * 15 cm format, the resolution will be more than 300 units.
Sometimes it turns out that images with resolutions of 150 and 300 units look exactly the same. Why is this and what does it depend on? Depends on the genre of the picture and the distance from which it will be viewed.
The documents
Document formats are measured in cm!
- For different kind certificates - 3 * 4 cm;
- For visas - 3.5 * 4.5 cm;
- For a passport - 3.7 * 4.7 cm;
- In a personal file - 9 * 12 cm;
- Residence permit - 4 * 5 cm;
- For passes - 6 * 9 cm.
Another range of formats
The main thing is that the photo frame matches the photo. Therefore, manufacturers produce special paper with certain sizes:
- A8 (5*7cm);
- A7 (7*10cm);
- A6 (10*15 cm);
- A5 (15*21cm);
- A4 (21*30cm);
- A3 (30*42 cm).
Why choose the right paper? As a result, you don't have to look at an incomplete, cropped image, or crop white margins that are redundant. Usually, the photo salon presents formats for printing with examples.
Order Features
If you place an order via the Internet, the system, when sending the image, says which parameters would be more appropriate for obtaining a high-quality image. If you choose the format of your choice, and not recommended by the program, then the administration does not take responsibility for getting poor quality.
It would seem that in the modern age of digital technology, why print photographs, because most photos are viewed in digital form. Knowledgeable people say that a photograph comes to life only when it is printed on paper, has a frame and hangs in a room to decorate the interior.
Remember that before printing, you need to select certain options that will affect the quality of the printed image.
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All the best to you, Timur Mustaev.
Click on the picture to watch the video.
You will learn:
- What is image resolution and what are the file formats.
- How to change the size and resolution in the Image Size window.
- What are the interpolation algorithms.
- How to prepare an image for posting on the Internet using
- the Save for Web window.
- How to get minimum file weight when saving as JPG and GIF.
- How to save as PNG, PNG-24, TIFF, PDF and PSD.
The lesson consists of the following sections:
1. Instructional video.
2. How does Resolution (Resolution) affect the quality of the image.4. Increase in size without loss of quality.
5. Plugins for resizing images.
6. Prepare the image for posting on the Internet.
7. Save for Web.
8. Saving in JPG format.
9. Save as GIF.
10. Saving in PNG format.12. Save to PDF format.
13. Save to PSD format.
14. Questions.
15. Homework.
How Resolution affects image quality
We have already mastered the basics of the program, made our own works and now we want to show them to others. This section will discuss how to do it right. The quality of a photograph depends on many factors. One of the most important is resolution.
Resolution is the number of pixels that make up a bitmap. Many of you have come across a situation where the resolution was deliberately reduced in the camera (more photos will fit into the memory card, and they look good on a small display). Remember the first cameras in mobile phones with a resolution of 0.3 MP. And then, transferring the photos
into a computer on a large monitor, were disappointed with the quality, which was irretrievably lost at the time of shooting. When you increase those photos in a graphic editor, the result becomes even worse. Slanted lines become jagged and the photo appears blurry. Pixels determine how sharp an image appears to us, and their number is responsible for the maximum print size without quality loss.
At the bottom left of the program window is the Status Bar.
Here you can change the display scale. Next to the scale column is information about the document. By clicking on the arrow, you will be taken to an additional menu. Choose the commands that you think are necessary for you to provide information.
This field is convenient, but does not allow us to resize according to our requests.
To change the resolution or size select from the menu Image(Image) -Imagesize(image size). Or clickalt + ctrl + I.
From the opening menus of fields Width (Width) and Height (Height), located in group Document Size (Document size), select units of measure. Percentages, inches, cm, mm, points, pc, columns.
dpi - dots per inch (dots per inch) - Units for printing resolution.
ppi - pixels per inch (pixels per inch) - Resolution units for computer monitors.
Resolution(Resolution) is the number of pixels in 1 inch or centimeter. What resolution to choose?
72 ppi is enough to display photos on the monitor screen. For Web-graphics, this is also enough. When you zoom in on such images, you will not be able to see fine details, because they are not there.
300 ppi - preferably set for photos that you want to put up for sale or print on a printer. Although for printing, the average is 267 ppi. For high-resolution images, when you zoom in, you can see fine details.
Choose pixels / inch (pixels per inch) as units, not pixels /cm. We, who are not accustomed to measure in inches, need to be especially careful not to choose pixels /cm just because centimeters are more to our liking. A difference of 2.54 times will immediately affect your resolution. The files will become gigantic. So when working with this window and when creating a new document, make sure that pixels per inch are selected.
Scalestyles(Scale Styles)- allows you to scale the styles specified in the palette Layers (Layers) along with the selected layer.
ConstrainProportions(Keep aspect ratio)- bind height and width, so that when one parameter changes, the other also changes. The most common mistake for beginners is the lack of this checkbox. As a result, the image is flattened or stretched.
Resample Image (Interpolation / Track changes). When this checkbox is checked, changing the image resolution (number of pixels per inch) will resize the image while maintaining the original resolution. If you clear the checkbox, then increasing the image resolution (for example, from 72 to 300) will reduce the geometric dimensions of the image when printed. Be careful not to end up with a postage stamp-sized print.
Interpolation algorithms can be selected from the drop-down list. Depending on this choice, the result is different. It's worth spending a little time to test them in action.
When the resolution is reduced, there are usually no problems, because the graphic information is simply discarded. But to increase the image, the program has to generate new pixels based on the analysis of their neighbors. When adding new pixels, the program does not always give a result that would satisfy us.
Resampling always comes with a loss in quality. Except for pixel-reducing interpolation to eliminate scanning defects and excessive graininess in the image. When scanning, select a resolution much larger than you need. Perform resampling with reduction in several stages. Grain and other artifacts will be eliminated.
Nearest Neighbor (By neighboring pixels). Maintains sharp edges. The simplest algorithm
as a result of which the edges have characteristic jagged edges.
Bilinear (Bilinear). The average value is calculated based on the analysis of neighboring pixels horizontally and vertically.
Bicubic (Bicubic). Best for smooth gradients. The average value is calculated based on the analysis of neighboring pixels, not only horizontally and vertically, but also diagonally. This interpolation method works with a large number of adjacent pixels, makes serious calculations of the values of these elements, and creates new pixels that should be in this place. With small magnifications of the photo, this method is quite suitable.
Starting with CS and above, two new interpolation algorithms have appeared. I advise you to use them:
Bicubic Smoother (Bicubic smoother) Best for enlargement.
Bicubic Sharper (Bicubic sharper). Best for reduction. If you're downsizing your shots the most, set this algorithm as the default. To do this, select it in Edit (Editing) - Preferences (Settings) - General (Basic). The changes will take effect after restarting Photoshop.
Upscaling without loss of quality
I found on the Internet an easy way to increase the size of an image with a slight loss in quality and decided to check it out. I took a small picture of 5 by 5 cm and increased it by 2 times using Bicubic Smoother interpolation (Bicubic smoother). To the right of the Width (width) and Height (Height) fields, select the% (percentage) element. Enter 110 in these fields to increase the size of the image by 10%.
Increasing the size of an image by 10% does not degrade its quality! To enlarge a small image many times over, you need to increase its size by 10% several times (8 times I had to run this command).
Then I decided to record an Action to gradually increase the image, in the hope that the quality will be better and I will be able to use this formula at the next increase.
By the way, this is very easy to do: open the Action palette (Operations / Scenarios). It's next to the History palette. Click the Create New Operation button. A window will appear in which you need to enter the name of the operation (for example, increase by 2p by 10). The circle at the bottom of the palette will turn red, which means the recording has begun. Change Image Size (Image size), as described below 8 times, and click on the leftmost box "Stop". Everything! Now, to perform this operation, it is enough to mark it with the cursor and press the Play button. You will find detailed information about Action (Operations) in the lesson on automation.
The results of the experiment are presented below. Do you see the difference? Me not. But maybe my eyesight is failing me. It seems to me that both results have become noticeably worse compared to the small source.
So is the game worth the candle if the difference is barely perceptible? And did people come up with this algorithm in vain? No, not in vain. There is indeed a difference, but it is noticeable only at very high magnification (300% and above). The blurring of the image after the Resample Image (Interpolation) will be visible only when printing the image, on the screen it
When using the transformation tools (Ctrl+T), the size of the image also changes. Moreover, this happens so quickly that we do not even have time to think about how much the quality will suffer. Interpolation algorithms mercilessly eat pixels when they are reduced and draw new ones when they are enlarged.
Plugins for resizing images.
Photoshop has a lot of tools for resizing an image. However, other manufacturers should also be noted.
- Alien Skin - BlowUp v1.0 plug-in for Adobe Photoshop. Better than bicubic interpolation. The plugin maintains smooth, sharp edges and lines when resizing an image, and creates 4x (1600%) magnifications without the appearance of step artifacts and glows. In some cases, Blow Up allows you to enlarge the image by six times without visible artifacts.
- SizeFixer SLR - Allows you to enlarge the image up to A1 format
- Size Fixer XL . - Limitless magnification.
- PXL SMARTSCALE - Zooms in up to 1600% with no loss in print quality.
If you set yourself a task, you can find other worthy representatives. I will not advise anything. Personally, I find it convenient to use one Photoshop program. But time goes fast, maybe when you read this text there will be a new super plugin or software that I don't know about yet. Well, we will continue to change the sizes and resolutions using Photoshop.
We will prepare the image for posting on the Internet.
The usual Save (Save) Ctrl + S and Save as ... (Save as ...) Shift + Ctrl + S do not allow you to control the result, and the file size is large.
Despite the fact that the save window has a slider that controls the compression quality, the file size is still larger at maximum quality than when another command is selected. Save for Web.
Select from the menu file(File) – Saveforweb(Save forweb). The key combination Alt + Shift + Ctrl + S. In this window, we can observe how the quality changes when the image is compressed. As well as control the size of the file and the speed of its download. It is most convenient to work with tab 2 - Up (2 options), because you can compare how much the quality will suffer for the sake of small weight (it is important that the pictures on the site load quickly). Below the image are comments: compression format, file size after optimization and download time.
The right side of the window contains all the main optimization settings.
There are five save formats for the Web: GIF, JPG, PNG-8, PNG-24, and WBMP. The latter is practically not used.
IN JPG it is best to store bulky site background files and photos for publications, in GIF, PNG-8 and PNG-24 - design elements that have a small amount and a limited number of colors. Unfortunately, PNG-24 is not supported by Internet Explorer 6, but the number of IE6 users is rapidly decreasing, and therefore the risk that the PNG-24 format will not open on someone's computer is reduced.
GIF and PNG-8 files retain transparency (but not the alpha channel). To preserve transparency, check the Transparency checkbox. WBMP is a bitmap format for mobile phones.
After you click "Save" and enter a file name, this window will appear. It is only needed to remind you that writing the file name when saving is better in English letters, without spaces and capital letters. If you do not want to see him in the future, check the box " Don't show again."
Save in JPG format.
JPG – the most common format for storing photos. The advantage is the relatively small file size. The main disadvantage is lossy compression. Small details are lost, stains and moiré appear. Repeated rewriting results in a gradual distortion of detail, resulting in a significant loss of quality.
The settings for the JPG format consist mainly of setting the image quality (aka compression) as a percentage. To save a large piece of the background, you can increase the blur.
To control the size of the image in Save for Web (Save for Web) there is a section called Image Size (Image size). The size of your image should not exceed 800 by 600 pixels. Or an impatient user will close the browser window without waiting for the image to fully load.
Open the boat.jpg file. Select the Save for Web command from the File menu. Select 2-Up mode (Two options). In the Image Size section, reduce the image size to 450*600. You can do this in advance by selecting the menu Image (Image) – Image Size (Image size), or by pressing Alt + Ctrl + I.
In the right part of the window, select the JPEG save format from the list.
List Compression quality offers several values - from Low (Low) to Maximum (Best). More precise adjustment is carried out by the slider Quality (Quality), located to the right. First, set it to 100%. With such a high value, the image
on the right side of the viewport (optimized) is almost identical to the original
on the left side. Take a look at the information fields in the respective parts of the viewport. The original (uncompressed image) is 625 KB, while the compressed image is 139.5 KB. Even with this low compression ratio, there is a significant gain in file size. Compressed image load time of 26 seconds is too long, many can lose patience and leave
from your page.
Set the slider Quality (Quality) in the middle, about 50%. Can you see the difference between the two images? Not? Then you can reduce the Quality a little more. Let's stop at 35%. Below 30, deterioration will already be noticeable. The weight became 23 kb, and the speed was 5 sec. Sometimes the Blur option can save you another second or two. But in our case, it will not give a noticeable result, because. we have already compressed the image quite strongly.
Progressive (Progressive) sets the progressive scan of the image when loaded in the browser. This option allows you to progressively load the image. From the very beginning of the download, you will see part of the image.
Optimized (Optimization / Optimized) includes additional optimization of the internal structure of JPEG, which sometimes further reduces the file size.
ICC Profile (Embedded Profile/ICC Profile) allows you to embed a color profile in an image file. An embedded profile increases the file size. Check this box only if you think it's necessary for others to know what color profile you have.
Click on the view button and you will see how your image will open in the browser. You can choose to view any of the browsers installed on your computer.
Save your settings if you need to process a lot of images. To do this, click on the priming menu icon and select Save Settings. Enter a name in the File name field and click the Save button.
The name you entered will now appear in the Settings list. When processing the next file, it will be enough to select this name from the list.
Save as GIF
To place images with transparent areas on a Web page, use the format gif A that only supports indexed colors.
The number of colors in its palette is set in the field colors and should create a relationship between quality and weight.
In the list of algorithms for generating an indexed image palette, by default, the option Selective, which produces the best results for images.
Next dropdown default option Diffusion (Diffusion / Random) better use for photos, a Noise– for background textures and gradients. Pattern (Regular / Pattern) creates a repeating pattern.
Interlaced– to gradually load the image.
The degree of smoothing is set by the slider Dither (Dithering / Smoothing). The higher the anti-aliasing, the larger the file size.
List Matte (Matte/Border) creates a transition from the edge of the image to the background color of the page. Usually the edge is translucent, which is not supported by the GIF format.
As a result, there is a characteristic noise during export. To avoid it, set the background color of the Web page in the list. Translucent pixels will be filled with this color. If you uncheck Transparency (Transparency), the color specified in the list Matte (Matte / Border) will be considered background and will fill the transparent areas of the image.
The translation of colors to the Web palette is carried out by the slider Web Snap (Web colors). Watch the colors of the image change depending on the position of the slider. Changes that occur are displayed in the image palette. White diamonds appear on some colors of the palette.
Color Table useful not only for observation. It allows you to control the individual colors of an image.
Clicking on the icon will open an additional list.
If you want to avoid significant color shifts in all browsers, but don't want to cast all colors to the Web palette, then you can do it selectively. Set the sort mode to Sort by Popularity. The most common colors are listed from left to right.
Click on any swatch in the palette. The swatch will get a white border to show it is selected. Photoshop can choose the closest color to the selection from the Web palette. To do this, click on the cube icon at the bottom of the panel or select the command Shift / Unshift Selected Colors to / from Web Palette (Replace / Cancel the replacement of selected colors with the colors of the Web palette).
Bringing the whole image to the Web palette made the transitions on the monitor image too sharp. Let's fix this defect manually. Double-click on the sample in the palette. The Color Picker window will appear in front of you. Make sure the Only Web Colors box is checked. Select the shade closest to the current color and close the window by pressing the OK (Yes) button. The color will be edited. If you find that too unsuccessful, open the Color Picker window again and pick another one.
A white square in the bottom corner of the swatch indicates that the color is blocked. Blocked colors remain intact when reducing colors in the image palette and when viewed in a browser. To unlock, click on the padlock icon
at the bottom of the panel.
Save in PNG format.
PNG allows you to store both indexed and full color images. The compression algorithm used does not lead to information loss. Multiple processing and rewriting is devoid of the disadvantages inherent in the JPG format. PNG-8 for indexed images and PNG-24 for full color. PNG-8 parameters are absolutely similar to GIF, in PNG-24 there is only switching of modes Transparency (Transparency), Interlaced (Interlaced)
and parameters Matting (Matt / Edge Processing).
To save, use the Menu File (File) - Save as ... (Save as ...). In the file type field, select TIFF.
TIFF supports lossless compression at the cost of large increases in file sizes compared to JPG. This format is considered the best for saving scans, sending faxes, OCR, and in printing for printing. It is possible to save an image from different algorithms compression and no compression at all.
TIFF preserves transparency and alpha channels. In Photoshop, you can save a file containing layers.
TIFF stores ICC profile information. This makes it possible to keep colors unchanged when viewed on different monitors and when printed.
TIFF is widely used on both the IBM PC and Apple. This allows it to be used to transfer images from one hardware platform to another without losing content. Also, this format can be used to transfer data between different applications that "do not understand" each other's formats, but "know" TIFF. With such a transfer, many image attributes that are lost, for example, when transferring data through the Windows clipboard, will be preserved.
Save to PDF
PDF is a presentation format electronic documents(paperless office). The main advantage is that documents look the same on any device (screens, printers). Design elements do not move in different directions.
To save, use the Menu File (File) - Save as ... (Save as ...). In the file type field, select PDF.
In the Protection System section, you can set a password to open a file, print, save, and edit.
Save to PSD format
PSD is PHOTOSHOP's own format. It can save layers, masks, clipping masks, paths, text and other moments of unfinished work.
Questions:
- Which file format does not support lossless compression?
- What is the best interpolation algorithm for upscaling an image?
– Nearest Neighbor
– Bilinear (Bilinear)
– Bicubic (Bicubic)
– Bicubic Smoother (Bicubic smoother)
– Bicubic Sharper (Bicubic sharper)
- What resolution should be set to save images for the web?
- What needs to be done in the Image Size window (Image size) so that the image is resized while maintaining the original resolution?
- Set the Scale Styles checkbox.
- Check the Constrain Proportions checkbox.
- Set the checkbox Resample Image (Interpolation / Track changes).
- Uncheck Resample Image (Interpolation / Track changes).
- Uncheck the Scale Styles checkbox.
- Can I resize an image in the Save for Web window?
- Which file format cannot be selected in the Save for Web window?
Homework:
1. Open the photo boat.jpg. Save as JPG using Save for Web. Achieve the following indicators: image size 600 * 800 pixels; 39.49 k;
8sec / 56.6kbps
2. Open the photo boat.jpg. Save as GIF using Save for Web. I managed to compress it to 75 kb and achieve a download speed of 14 seconds at 56 kbps. Try to get the best result.
You have to change colors.
We present to you our selection of the most big photos in the world. You will need FlashPlayer to view them. You can download it separately or use the Google Chrome browser.
Photopanorama of the Moon - 681 Gpc.
The absolute champion in the size of composite photos is NASA. In 2014, the agency released a 681 gigapixel panorama of the Moon. On June 18, 2009, NASA launched the Lunar Reconnaissance Orbiter (LRO) to map the lunar surface and collect measurements of potential future landing sites, as well as for scientific purposes.
You can view the panorama on the website.
Photo panorama of Mont Blanc - 365 Gpc.
At the end of 2014, an international team of professional photographers led by Filippo Blegnini made a circular panorama of the mountain range between France and Italy - Mont Blanc, the second highest mountain in Europe after Elbrus.
It consists of 70 thousand photos! Photo taken by camera Canon EOS 70D with Canon EF 400mm f/2.8 II IS telephoto lens and Canon Extender 2X III. The creators of the giant panorama claim that if printed on paper, it would be the size of a football field. To date, this is the largest gigapixel photograph taken on earth.
You can view the panorama on the project website.
Photo panorama of London - 320 Gpc.
The panorama was compiled from 48,640 individual images taken with four Canon 7D cameras and posted online in February 2013. Preparation for the experiment took several months, and the shooting took place over four days. Pictures taken by British Telecom from the top of the BT Tower in central London on the north bank of the Thames. Photographed by 360cities.net panorama experts Jeffrey Martin, Holger Schulze and Tom Mills.
You can view the panorama on the website.
Photo panorama of Rio de Janeiro - 152.4 Gpc.
The panorama was taken on July 20, 2010 and consists of 12,238 photographs. Uploading the final image to gigapan.org took the author almost three months!
You can view the panorama on the website.
Photo panorama of Tokyo - 150Gpc.Fo
The panorama was created by Jeffrey Martin, founder of 360cities.net. The panorama was created from 10,000 different images taken from the observation deck of the Tokyo Tower television tower. When creating it, the photographer used a Canon EOS 7D DSLR and a Clauss Rodeon robotic car. It took two days to get 10 thousand frames, and three months to bring them into one panorama.
You can view the panorama on the website.
Photo panorama of the national park "Arki" - 77.9 Gpc.
The author of the panorama is Alfred Zhao. Arches is a national park located in the US state of Utah. There are more than two thousand arches formed by nature from sandstone. It took 10 days of processing, 6 TB of free hard disk space, and two days of uploading the final image to the site to create the panorama. The photo was taken in September 2010.
You can view the panorama on the website.
Photo panorama of Budapest - 70 Gpc.
In 2010, a team of enthusiasts sponsored by Epson, Microsoft and Sony created what was then the largest 360-degree panoramic photo in the world. The project was called "70 billion pixels of Budapest". The 70-gigapixel photo was taken four days from the city's 100-year-old observation tower. The panorama was over 590 thousand pixels wide and 121 thousand pixels high, and total amount pictures - about 20 thousand. Unfortunately, the link doesn't work right now.
Photo panorama on Mount Corcovado - 67 Gpc.
This photo was taken on Mount Corcovado in Rio de Janeiro (Brazil), where the statue of Christ the Redeemer is located. The photo panorama was made in July 2010 and was created from 6223 frames.
You can view the panorama on the website.
Photo panorama of Vienna - 50 Gpc.
A gigapixel photo panorama of Vienna, the capital of Austria, was created in the summer of 2010. It took 3600 shots to make it, but the result was worth it.
You can view the panorama on the website.
Photo panorama of Marburg - 47 Gpc.
Marburg is a university town with a population of about 78,000. The panorama took 5,000 shots, which were taken with a Nikon D300 camera with a Sigma 50-500 mm lens from a tower 36 meters high. Each of the photographs has a size of 12.3 megapixels. It took the author 3 hours and 27 minutes to shoot, and the total amount of information he received took up 53.8 GB of hard disk space.
You can view the panorama on the website.
Milky Way - 46 Gpc.
For five years, a group of astronomers from the Ruhr University, using an observatory located in the Chilean Atacama Desert, followed our galaxy and created a giant photograph of 46 billion pixels from images of the Milky Way. The image weighs 194 GB.
You can view the panorama on the website.
Photo panorama of Dubai - 44.8 Gpc.
The author of the panorama is Gerald Donovan. Dubai is the largest city in the United Arab Emirates. Used to create a panorama Canon camera 7D with 100–400 mm lens. The author worked for more than three hours in 37-degree heat and took 4250 photographs.
You can view the panorama on the website.
Photo panorama of the backyard - 43.9 Gpc.
The 4048 panorama photos were taken on August 22, 2010 in the village of Round Lake, Illinois, USA. The author, Alfred Zhao, used a Canon 7D camera with a 400 mm lens. The shooting took two hours, but the processing of photos took about a week.
You can view the panorama on the website.
Photo panorama of Paris - 26 Gpc.
The author of the panorama is Martin Loyer. At the end of 2009, the interactive site www.paris-26-gigapixels.com appeared on the Internet, which has a huge gigapixel photo panorama of Paris with very clear resolution, consisting of 2346 photos. It will allow you to immerse yourself in the image of this city and see its sights without leaving the house.
This is not so much a translation as a retelling of an article published on the website www.luminous-landscape.com.
What is the resolution of my camera?
What should be the resolution of the photo?
Whether to post a photo high resolution in the Internet?
If the image consists of dots smaller than this limit, it appears to the eye to be continuous, continuous. The entire printing industry has been built on this feature of the eye for decades. Every photograph and every picture you see in any book, magazine, calendar, art print, is made up of dots of paint with a resolution typically ranging from 70 to 300 (occasionally more) dots per inch.
Timiryazevsky park by moonlight.
Digital images, whether they come from a digital camera or are scanned, are subject to the same rules. If the print resolution was too small, then we "see dots". This happens, for example, when you look at a poor quality photograph in a newspaper.
What we end up seeing is pixels. These are the discrete elements that make up the image created by the optical system of a digital camera or scanner on a sensor. Pixels are the equivalent film grain. The problem arises when we try to understand the relationship between what is photographed and what will be printed.
This picture shows the menu item dialog Image->Size in Photoshop for the photo "Timiryazevsky Park in the Moonlight", which you saw a little higher. It was obtained using digital reflex camera Canon EOS 300D.
(What follows applies equally to scanned images. The principles are the same.)
The information at the top of this window tells us that the camera took a picture 3000 pixels long and 2040 pixels wide. The image size is 17.5 megabytes.
The bottom section of this window shows that the current settings for this image are 25.4 x 17.3 cm, and that the resolution for this image is 300 dpi. Please note that in the box Resample Image there is NOT a checkmark at the bottom.
Photo start and end resolution
If you try to change only one of these values - length, width or resolution ( Width, Height or Resolution), then the other two will change simultaneously. For example, you made the length equal to 20 centimeters, but the width changed to 13.6 centimeters, and the resolution became equal to 381 ppi, as seen in the picture below.
This happens because in itself the digital image does not have an absolute size in centimeters and does not have a resolution. Its only characteristic is the number of pixels in length and width. It does not have measurements in centimeters or inches. Obviously, the resolution will change depending on the physical dimensions of the image, because the number of pixels will be distributed over a larger or smaller area. The resolution changes according to the size.
Now let's say you want to print this photo in a "very large" size - say 60x40 cm. But in reality you will have to stop at something like 50x33 cm, because the resolution of the image will drop to 155 ppi. Even this resolution is not enough for high quality printing, as we will see below.
Free extra pixels
Actually, nothing is completely free, but you can still get some additional permission if you need, but within certain limits. You probably noticed that at the bottom of the Photoshop dialog box there is a special box at the bottom (“checkbox”) called Resample Image. If you check it, then photoshop disengages
rigid relationship between length, width and resolution (between the values Width, Height And Resolution). By checking this box, you can change each parameter independently.
That is, when this checkbox is checked, you can set the image any size And any resolution- whichever you want! Well, isn't it a miracle?
In this example, I ordered Photoshop to resize the image to 60x40 cm, and so that the resolution is 360 ppi. But, as you can see at the top of the dialog box, doing so will increase the file size to 140 megabytes, and the original image "weighed" 17 megabytes.
Where did this extra resolution and all those extra bits in the image come from? They were invented by photoshop. In the same way, when scanning a scanner with a resolution greater than its real optical resolution, scanner composes additional pixels that he is not really able to see. Both the scanner and Photoshop, based on real data, compose additional pixels to insert them into the gaps between the “real” pixels. There is no additional information in these "fake" pixels.
"well, OK", you might say, " there is no new information in these pixels. On a fig then insert them?"
In fact, if you do this in moderation, you can make an image larger than the original, and at the same time visually it will be perceived quite well. Usually such "fake" pixels are inserted when an image is going to be shown from a distance (for example, a billboard or a poster), and this effect is almost imperceptible. But if you look at such a picture up close, then its quality will not please you.
The key point here is moderate doses! There is another alternative to Photoshop - this is a separate program called Genuine Fractals. It uses a completely different mathematical algorithm than the one Photoshop uses. As far as I know their discussions in different forums, Genuine Fractals does this operation much better than photoshop.
But in any case, the larger the original image in pixels (and the better its quality!), the more you can stretch the image (or increase its resolution).
And finally, sometimes you may need to reduce the resolution.
If you are preparing a picture for posting on the Internet, then you will have to set the standard screen resolution to 72 ppi. You need to check the box Resample Image, enter value 72 ppi, and then specify the desired length and width in pixels ( Width And Height) - so that the picture fits on the monitor screen. Photoshop will discard the extra pixels and create a file of the appropriate size.
What permission do you need?
The final question: what resolution will be enough? The answer depends on the device on which your image will be displayed or printed. For example, pictures on a monitor screen usually need 72 ppi. For photo frames - even less. If the file has a higher resolution than required, then you simply will not see the difference on the screen. (The image may even look a little worse - it depends on what program the image is displayed on the screen). But the main trouble here will be that a large file will simply take longer to load. That's all.
Cool printers in good labs require a different permit. For example, the LightJet 5000, a very popular wet printer, requires files with a resolution of exactly 304.8 PPI. Ask your favorite photo lab what resolution you need for high-quality printing on their equipment.
Inkjet printers
Most amateur photographers today print their photos on home inkjet printers. Very popular are printers of the family Epson Photo, so I'll take them as an example. In the specifications of these printers, for example, for models 870/1270/2000P, it is indicated that they print at a resolution of 1440 dpi. This means that they can put 1440 dots on one inch.
But!
They use 6 different colors to print color images. Therefore, each pixel of the image will actually be printed using several dots of a different color - two, three, or even all six colors. Therefore, your printer will have to print more dots than there are in the image.
If you divide 1440 by 6 you get 240 . This is the real minimum image resolution that is needed to get a high-quality photorealistic image on Epson printers that have a resolution of 1440 ppi according to the passport. Many printer owners (including me :) believe that a 360 ppi output file will give several the best quality than 240 ppi. True, if I make a print of a large format (A3, for example), I rarely make a resolution of more than 240 ppi - anyway, large prints are not considered at close range.
PPI and DPI
Notation PPI(Pixels per Inch) and DPI(Dots per Inch) are often used interchangeably. Actually, this is not true, but this is not a big problem, because usually we understand what we are talking about.
To be absolutely accurate, let me remind you that when it comes to scanners, digital cameras and monitors, it is correct to talk about PPI, and the characteristics of printers and plotters are indicated in DPI.
Now you know exactly the difference.
Final Thought
Here we talked about such concepts that are easier to feel by playing with them in Photoshop or other software than to learn them from printed text. So really, try to play around with the size and resolution in Photoshop, increasing and decreasing the size of the image, evaluating the result by eye.
And finally, when you save your files after resizing and resizing, always make sure that your original file with original dimensions and res will not be overwritten. Only when the original is securely stored in a secluded folder on the disk, you can start experimenting with changing the resolution.
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Pixels, in turn, are a set of dots. And the photo consists of these dots, each of which has its own color and shade. The more dots, the deeper and better the image will be.
Any image a person perceives by sight. And vision is limited even in the most healthy people. And this limitation is about 70 dots per 1 cm or 200 per 1 inch (as resolution is usually expressed). If there are more points in a centimeter, then the human eye will perceive them as a solid line.
What is DPI?
It is on the possibilities of vision that the printing principle is built. Almost every illustration printed matter has a resolution of 90 to 300 dpi. This dependence is called dots per inch or DPI for short.DPI only matters when the image is printed directly. A photograph that is on a computer screen does not have a specific size: length and width. And as mentioned earlier, these two parameters are the main ones when calculating the extension.
The main task of the extension is to take a high-quality picture when it is printed on a printer.
How to take a good quality photo?
To prepare a photo for printing, you need to make some settings in the photo editor. The most suitable editor is Photoshop. After you open the photo in the program, go to the "Image Size" section.The window that opens will show three main fields: width, height, and resolution. When you change the resolution, the height and width will change, and vice versa. If you check the box next to "Track changes", then you can adjust the dimensions independently of each other.
The optimal resolution for a good photo, which is supported by most printers, is 300dpi. But the smaller the image should be as a result, the less resolution you need, and vice versa. Before printing a large format photo, take an interest in the characteristics of the printer: the main parameters are PPI (maximum possible resolution) and the number of colors used in printing. To reveal the true DPI value of a device, divide the PPI by the number of colors.
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