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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 ...


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 ...


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 ...


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

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

This answer assumes competence on the part of the photo lab you're using. If you think they're not competent, then use a different photo lab instead, rather than trying to work around their lack of competence - because if they're incompetent in downsizing images, they're probably incompetent at other things as well. Facebook's primary business isn't driven ...


4

PPI is unimportant and meaningless in a camera picture (inches of what?). The only thing that matters is the actual size in pixels. The only kind of capture where the PPI matters is a scan, because it lets you print the image at its initial size. Otherwise the PPI it is just an indication of the intended size, and can be changed at will...


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

Pixels Per Inch, or PPI, is a measure of density or resolution (resolution in the sense of fineness of detail, which again refers to the density of information, rather than dimensional resolution, or the physical parameters). Not all devices that can be used to view photos have the same pixel density. Computer screens tend to range from 72ppi to 109ppi in ...


3

300 would hold up better if people will view it up close, but then again, for up close viewing, chances are the tiles are going to be more visible. If the ideal viewing distance is a bit further away, anything upwards of 150 is fine, though the higher quality you can pull off, the better, so I'd go with 200PPI if you have a native resolution of 600PPI. If ...


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

There won't be an impact to photography itself. The display medium is changing and that means that better details in displayed images but prints require more resolution still. This is not as new as you think. Over 10 years ago, I had a loaned IBM T220 on my desk which is a 9 megapixels display. The precision was incredible and while the list price dropped ...


2

PPI (pixels per inch) value of a digital image is only metadata used to determine how large an image should be printed. You can set the value to be whatever you like, without having to resize or do anything with the actual pixels. For example if you took your 4000 x 3000 image at 240PPI and placed it into Adobe InDesign it would end up 16.6 x 12.5 inches ...


2

When it comes to Sharpening settings I would say it comes down to personal preference. I do not use the tool for Output Sharpening when exporting, any sharpening needed I do in the Develop module. As for resolution the web browsing "standard" is 72dpi (ppi). But keep in mind that this number does not really matter. In almost all cases of viewing a picture ...


2

Note: in this answer the word 'resolution' is used in the optical sense: "the ability of an imaging system to resolve detail" (Wikipedia). I think your question has some of the answer in it: They have certainly taken display technology closer to the print medium quality. I think that is the goal. What would a perfect display be? Be visible in both ...


2

There's no difference. The statements you are seeing are uninformed. There are a lot of uninformed people on the internet, so that's not surprising. You haven't missed anything, except maybe you are overestimating the reasonableness of typical comments you might find online. :)


2

The variability of size and positioning precision of one "spit", as it's called, varies with printing technology and model lines over time. As I recall, one particular printer I studied (and some generic lore mixed in) you have a certain volume of ink (a few picoliters) ejected with one action from the nozzle. Several such quantum spits can be performed ...


2

First, the "size" of your image is absolutely NOT measured in kilobytes. That is only the file size, which largely depends on the degree of compression you choose. Due to the JPG Quality factor selected, larger JPG files are better quality, and smaller JPG files are lower quality (lower quality is not normally the best choice), but the image size in pixels ...


1

Most likely, you saved it in Photoshop with menu File - Save for Web. Which is fine, it is still the same image, but that "Save for Web" purpose is to remove all of the Exif data, which is where the JPG dpi number is, so it disappears. That saves a few bytes, and video monitors have no use for the dpi number anyway. Menu File, Save As (JPG) will Not ...


1

For JPEG images the size of the image in pixels plus the complexity of the images (and some other factors) influences the size of the image file in kilobytes, but there isn't necessarily a 1:1 link. So don't worry about that too much. Also, the PPI is metadata (information about the image, instead of information in the image), so Photoshop doesn't always ...


1

To get the maximum quality you would usually send the native resolution. This will rarely be a nice and round number. This is because a printer can discard extra but it cannot make up for missing details. It also avoids double resampling since a printer has to convert to its inner resolution and resolution. Say your 80 MP is 10328 x 7760 pixels, then a 36 x ...


1

From https://en.wikipedia.org/wiki/Image_sensor_format#Smaller_sensors ... the 2/3 inch sensor size is 8.8 x 6.6 mm. I don't know your image size, but from the 2,200,000 pixels, the calculator at my site at https://www.scantips.com/mpixels.html says it has to be about 1712 x 1288 pixels if 4:3 aspect ratio. (or 1976 x 1112 if a native 16:9 chip, but ...


1

There are different topics here. Forget the PPI for a moment. 1. What is your starting file size in pixels? What is the resolution of your scans, or photos? This is the main issue here. Of course, if your original files are big enough you can print them big enough. If they are not, you probably need to make a new scan or use a good DLSR, good ...


1

The 300 ppi is a norm derived from colour printing with offset, where the images had to be transformed to grids of separate points. Iirc, those grids were closer to 150 dpi, which corresponds to 300 ppi (1 coloured point + 1 space). Also, the result was expected to be viewed from normal reading distance (~30cm), where the human eye just can't distinguish the ...


1

Probably we could have a theoretical discussion on angles, distances, distortions, focal planes, etc. But probably it is simply easier to print a grid of perfect squares of 1x1 inch each and take a photo. Then you grab your photo and count pixels in each zone of your image. If the grid is at a small distance you will have a lot of distortion, which you ...


1

Your image is 250x350 pixels. The dot-pitch of your monitor (92ppi) is irrelevant. The image will have a resolution in dpi (dpi - dots-per-inch - for printing, ppi - pixels-per-inch - for on-screen display) attached to it, and the 'default' is 72 ppi, but that's just a label (It's 72ppi for historical reasons - the dot-pitch of the early Mac monitors which ...


1

I don't think it will have any effect on photography, in any case displays will always lag significantly behind camera resolution. By the time we actually have 5 megapixel displays we'll probably have 80 megapixel cameras! Fundamentally size and viewing angle are more important than resolution (in terms of numbers of pixels). Unlike digital images, which ...


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