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46

You ask if there is a practical difference. So the answer is yes, albeit a very small one, but some of the other answers have missed it. You're right that the only difference is in the metadata: if you save the same image as 300dpi and 72dpi the pixels are exactly the same, only the EXIF data embedded in the image file is different. (I've even verified this ...


28

"we may require the originals of the awarded photographs to be submitted by the relevant participants, with a short side of minimum 2200 pixels and bit depth of 300 dpi." and " Contest photographs must be saved in the jpg/jpeg format, 150-300 dpi and 7-12 compression quality, with a short edge of minimum 1920 pixels and a long edge of maximum 3200 ...


21

I'm going to sort of disagree with all the other answers that talk about DPI or PPI rules of thumb, and suggest two different 'rules' (based on PPD, from another answer of mine) Rule 1 — The 'Retina' rule (aka the Pixels-Per-Degree (PPD) / 'better than your eye can see' rule) This comes pretty much straight from Apple's Retina display designs, the idea ...


17

The straightforward answer to your question is very simple arithmetic: 32×300 = 9600 and 18×300 = 5400, so 32 inches by 18 inches at 300 dots per inch is 9600 by 5400. However, it gets a little more complicated when you consider a more complicated relationship between pixels and colored dots in your output medium. For details on this, take a look at jrista'...


15

Does an image edited and saved/exported with 1200x800 pixels at 300 ppi look any different online than the same image saved/exported with 1200x800 pixels at 72 ppi? No. A bitmap produced either on-screen or on paper from the image will be identical. The only difference would be the default print size from some applications, and only then if the image size ...


13

The image I uploaded was rejected because it was under 300 DPI. The DPI is just a number which has no relevance to a digital image. It relates only to printing and not the quality or resolution of the image itself. If you change the number to 300 DPI in an editor, it should be accepted. As you have Windows 10 and presumably use assistive technology to e....


10

Image resolution/pixel dimensions are the attributes you should probably be looking for. To find out what numbers you should specify in your requirements, you'll need to decide on the maximum size that you'll want to print an image from the archive, then from that you can derive the minimum resolution that images in the archive should have. For example, if ...


6

Every digital image has a specific size: the width and height in pixels. The amount of information depends on that. In digital image files, the number of pixels per inch is just a hint. It indicates a proportion that should be used for calculating the actual size of the image when printed. If you have an image of 1000x1000 pixels and you print it at 100ppi,...


6

Imposing a minimum DPI value is meaningless as images do not have any intrinsic physical dimension. A better approach is to work out the maximum size you want to guarantee to be able to print, work out the image size in pixels necessary to achieve 300 PPI at this size, and then impose a minimum on the image dimensions in pixels.


6

You understand the situation (that dpi number does not affect the pixels), and in this situation (before considering actually printing the image), always setting 300 dpi is a good politically correct action that will please those that don't understand what it means (or doesn't mean). Digital image size is specified by dimensions in pixels, not by inches. ...


6

The idea that you will get better prints at exactly 300dpi — where one dot is also one pixel — is a misconception. There may have been a limited time and certain circumstances where it was true, but that's not the case now. There is no harm in having more pixels. You should be able to find 12×9" prints and frames relatively easily, and print at around ...


5

It depends on a few factors - primarily the print technology that is going to be used, and secondly what the print is to be used for. The D700 shoots at 4256 × 2832 (12.1 MP), so the largest Square frame you can print at 1:1 pixel ratio would be 2832 x 2832 pixels. Lets say the print is to be at 600 DPI, which is a fairly standard high quality signage dpi, ...


5

Pixels per inch don't actually exist until the image is rendered onto some physical medium such as paper or the monitor on your computer. The device doing the rendering determines PPI and PPI determines how large the image will appear when rendered. Rendering your 4000x3000 on a device capable of producing 240 PPI would produce a 16.6"x12.5" physical image....


4

An image has no physical size, it is simply a collection of pixels. A 1280 pixel wide image will be rendered 20cm wide on my old computer monitor, but the same image will be rendered just 9cm wide on my phone. The DPI value embedded is metadata recording the "intended" physical size. As such it can be set to whatever value the user desires. The value is ...


4

The DPI setting (or PPI to be pedantic) only specifies how the pixels should be translated into absolute metrics. The 5400 PPI for the 900x500 pixel image only means that it represents 0.1667x0.0926 inches (4.23x2.35 mm) in absolute metrics. When an image is shown in the browser, it totally ignores the absolute metrics. The image is shown by its pixel size,...


4

You can use MS ICE for stitching together 3 photos, or use a 12k px linescan camera, panning over some wood, or go the computer graphics way. Wood textures are pretty common in 3D modelling software.


4

Assuming the photo is square (from the 36" x 36" max) It sounds like the largest photo they want is a 1200 x 1200 pixel image. You will need to compress your photo down to under 1200 x 1200 pixels and save it as a JPEG. The Dots Per Inch (DPI) is a way of telling the image viewing program the scale of each pixel. Some software programs allow you to view ...


4

What it means is that whoever wrote the rules probably doesn't have a clue how JPEGs are rendered using most current image viewing applications. DPI (dots per inch) is a term that, when used properly, refers to printer hardware. PPI (pixels per inch) is the way we refer to how many pixels of a digital image should be rendered per inch when the image is ...


4

I have written a more elaborate post in Spanish here, which Google translate can probably help you read. A simplified version. There is a unit for offset commercial printing called lpi. This is defined by the real resolution of a laser printing on a negative film or plate. Let us say the laser plate printer gives you 2400 dpi. If you need 256 tones of ...


4

You got it the wrong way round; the dpi setting stored in the file is nowadays just a historic and mostly useless number, and you could simply change it with a tool, but there is not even any need for printing. What you need to care for is the total resolution of the photo, which is limited by the camera hardware. You can reduce resolution, but never ...


4

Do the math. If you really need 300 DPI, then at most your picture can be (2500 pixels)/(300 pixels/inch) = 8.3 inches wide. If you want bigger than that you either can't, or you have to relax your resolution requirements. 200 DPI might still be good enough for something hand-held, for example. The resolution the picture needs to have depends on viewing ...


3

If the physical size of the prints isn't changing, i.e. remaining 13.3 x 8.85 inches, then I would say stick to the larger image at 320 DPI. If you print the same size image at 160 versus 320 you'll have less printed dots per inch, meaning the physical resolution of the print is smaller, and I would argue the lines and curves in the image would appear less ...


3

For this size 150ppp is already a good resolution. A1 is 33.1 in × 23.4 in you need (x150) => 4965x3510 pixel. That is 17.4MP, so if you use the full image (no crop) you'll be fine.


3

Another possibility is to create a texture, for example with GIMP. The option is Filter -> Render -> Texture. Start with a rectangular or square image of your wood and select it; ratio should be at least 2 (higher is sometime better), and select "seamless tiling" if you want then stitch together copies of the image. Results are normally better without the ...


3

As you wrote it, the answer is that there is no difference (until you print it or look at it in a document that will be printed). First a clarification: PPI is pixels per inch, a description of the resolution of the image. DPI is dots per inch, a description of the physical ability of the printer/scanner being used. pixels (on a side) = ppi x inches. ...


3

To put some rule-of-thumb numbers to it: a print resolution of about 300dpi is required for a high-quality print, but for non-picky print many people will be fine with 100dpi. Below that, even non-skilled viewers will probably object. So, in order to reduce the image below what might make a great print at 5x7, 1500x2100 pixels is the threshold. That's more ...


3

You simply need to set a low enough resolution. Set the image size no larger than the number of pixels to be displayed in the browser. Screen resolutions are generally lower than print, but it's still going to look "ok" printed by most people's definition even though it will clearly not be professional quality.


3

The big problem you have here is that your aspect ratio is wrong. A0 (or any other A size paper) has an aspect ratio of 1:sqrt(2) or 1:1.414 or so. Your image has an aspect ratio of 2048/1152 = 1.777. You're going to have to decide whether to crop your image, or print it "letterboxed". Other than that, see the question linked by mattdm.


3

Besides the algorithms described in other answers, small images' file sizes can be reduced by stripping out metadata from the file. EXIF/IPTC data can add up to 64 kilobytes to a JPEG image.


3

Nope. The number is purely fictitious. The vast majority of cameras always put the same number. You can even check it out by changing the size of image output and you will see that the DPI stays exactly the same. So, if your 24 MP camera outputs a 24 MP image at 6000x4000 which specifies 300 DPI, it should correspond to a 20" x 13.3" but if you set it to 12 ...


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