DPI of photo?
June 30, 2023 7:00 AM Subscribe
A friend needed some photos 400dpi or more and asked me to do it. I have a Samsung Note20 Ultra, and googling showed me the res was higher than that. However, all photos seem to be coming as 72dpi and I can't figure out how to change it. What am I not understanding here?
Response by poster: I don't understand your answer, bowbeacon.
In order to be high res enough to print, don't they have to have a certain resolution? The request says 400dpi but when I use Preview it says 72dpi. That number isn't fixed as I can change it in the box, but of course doing that makes the picture smaller proportionally and is therefore not good enough to print.
posted by dobbs at 7:22 AM on June 30, 2023
In order to be high res enough to print, don't they have to have a certain resolution? The request says 400dpi but when I use Preview it says 72dpi. That number isn't fixed as I can change it in the box, but of course doing that makes the picture smaller proportionally and is therefore not good enough to print.
posted by dobbs at 7:22 AM on June 30, 2023
A friend needed some photos 400dpi or more and asked me to do it.
It's important to know why they need the photos at 400 dpi, that way you can determine if he really needs 400 dpi. It most cases clients probably won't something that specific.
As to dpi, what matters in terms of your question is what size your friend wants to use the photos. 'Cause a 30 by 20 inch photo at 72 dpi, if those physical dimensions are decreased, increases resolution. Essentially as photos get smaller, they pack more dpi into that smaller space, so there's more dots per inch. This is simplified take on things, but a good explainer.
Most cameras take photos at 72 dpi and large physical dimensions. Manufacturers understand that users will shrink those physical dimensions when the photo is output to some device, like a printer and that'll increase the dpi/resolution. Storing photos on camera and phones at 72dpi is an easy way to keep file sizes small until a final use/size is decided.
So you don't have to change your dpi settings, but you do need to know what your friend's goal is with the photos. Long story short, I wouldn't worry about on your phone, am 95% sure it's fine whatever you friend will need, but it's always good policy to ask a client what the goal, especially is they're being specific about dpi. That often means they don't fully understand the process and are just quoting a number they heard/read/were told about.
posted by Brandon Blatcher at 7:22 AM on June 30, 2023 [3 favorites]
It's important to know why they need the photos at 400 dpi, that way you can determine if he really needs 400 dpi. It most cases clients probably won't something that specific.
As to dpi, what matters in terms of your question is what size your friend wants to use the photos. 'Cause a 30 by 20 inch photo at 72 dpi, if those physical dimensions are decreased, increases resolution. Essentially as photos get smaller, they pack more dpi into that smaller space, so there's more dots per inch. This is simplified take on things, but a good explainer.
Most cameras take photos at 72 dpi and large physical dimensions. Manufacturers understand that users will shrink those physical dimensions when the photo is output to some device, like a printer and that'll increase the dpi/resolution. Storing photos on camera and phones at 72dpi is an easy way to keep file sizes small until a final use/size is decided.
So you don't have to change your dpi settings, but you do need to know what your friend's goal is with the photos. Long story short, I wouldn't worry about on your phone, am 95% sure it's fine whatever you friend will need, but it's always good policy to ask a client what the goal, especially is they're being specific about dpi. That often means they don't fully understand the process and are just quoting a number they heard/read/were told about.
posted by Brandon Blatcher at 7:22 AM on June 30, 2023 [3 favorites]
you do need to know what your friend's goal is with the photos.
Exactly. In order for dots-per-inch to be meaningful, you need to know how many inches. DPI only makes sense if the image is intended to be printed and how big the print is going to be.
posted by 1970s Antihero at 7:30 AM on June 30, 2023
Exactly. In order for dots-per-inch to be meaningful, you need to know how many inches. DPI only makes sense if the image is intended to be printed and how big the print is going to be.
posted by 1970s Antihero at 7:30 AM on June 30, 2023
Response by poster: Thanks.
The purpose is to have a print-worthy photo.
Here are two of the pictures taken with the Note20 Ultra.
The friend submitted the photos to the gallery requesting them and they're the ones saying they're only 72dpi. The gallery got submissions from many other artists in my friend's class and we're the only ones being told they the wrong dpi.
At first I thought it was maybe because they're on Google Photos and being resampled to save space. But when I send the original photo from my phone (pre-Google Photos) to myself via email and open them on my Macbook, they also say 72dpi even though the file itself is much larger.
posted by dobbs at 7:31 AM on June 30, 2023
The purpose is to have a print-worthy photo.
Here are two of the pictures taken with the Note20 Ultra.
The friend submitted the photos to the gallery requesting them and they're the ones saying they're only 72dpi. The gallery got submissions from many other artists in my friend's class and we're the only ones being told they the wrong dpi.
At first I thought it was maybe because they're on Google Photos and being resampled to save space. But when I send the original photo from my phone (pre-Google Photos) to myself via email and open them on my Macbook, they also say 72dpi even though the file itself is much larger.
posted by dobbs at 7:31 AM on June 30, 2023
I would disagree with the first answer here - a JPEG will have an inherent DPI based on the number of pixels and the physical dimensions of the image. You can see this DPI number is practically any image editor, including the Windows file property dialog.
Now it's true that the DPI is sort of made up, because an image that is 72 pixels wide with a physical size set to 1 inch will be 72 DPI....but if you "resize" that image that image to be 0.18" wide it will then be 400 DPI even though the pixels and image data didn't change.
So the question here is how big your current image is, and what happens if you change the physical dimensions to get you that 400 DPI number. On a modern day phone I would expect it to still be usable rather than being, for example, .18" wide but it's going to depend on the specific image.
https://convert.town/image-dpi is a tool I found by searching online that was able to change an image from 96 dpi to 400 dpi, with no other apparent changes to the image - in fact, looking at the image they look the same on screen because that number isn't inherent to how it looks. It may work for you as well.
posted by Nonsteroidal Anti-Inflammatory Drug at 7:32 AM on June 30, 2023 [1 favorite]
Now it's true that the DPI is sort of made up, because an image that is 72 pixels wide with a physical size set to 1 inch will be 72 DPI....but if you "resize" that image that image to be 0.18" wide it will then be 400 DPI even though the pixels and image data didn't change.
So the question here is how big your current image is, and what happens if you change the physical dimensions to get you that 400 DPI number. On a modern day phone I would expect it to still be usable rather than being, for example, .18" wide but it's going to depend on the specific image.
https://convert.town/image-dpi is a tool I found by searching online that was able to change an image from 96 dpi to 400 dpi, with no other apparent changes to the image - in fact, looking at the image they look the same on screen because that number isn't inherent to how it looks. It may work for you as well.
posted by Nonsteroidal Anti-Inflammatory Drug at 7:32 AM on June 30, 2023 [1 favorite]
The friend submitted the photos to the gallery requesting them and they're the ones saying they're only 72dpi.
The confusion is probably coming from the fact that an 8x10 image (or whatever size you're printing) at 72 dpi - that is, 720 pixels tall - will not look great for printing. But if it's a 72 dpi image that is actually 55.56 inches tall - that is, 4000 pixels tall - then it will be 400 dpi when resized to 10 inches tall.
This was a common mix up going both ways when I worked in print, and I'm surprised the gallery is getting tripped up. They shouldn't just say it needs to be a certain dpi, they need to tell you the physical print size size and required dpi. One number on its own doesn't mean much.
posted by Nonsteroidal Anti-Inflammatory Drug at 7:37 AM on June 30, 2023 [10 favorites]
The confusion is probably coming from the fact that an 8x10 image (or whatever size you're printing) at 72 dpi - that is, 720 pixels tall - will not look great for printing. But if it's a 72 dpi image that is actually 55.56 inches tall - that is, 4000 pixels tall - then it will be 400 dpi when resized to 10 inches tall.
This was a common mix up going both ways when I worked in print, and I'm surprised the gallery is getting tripped up. They shouldn't just say it needs to be a certain dpi, they need to tell you the physical print size size and required dpi. One number on its own doesn't mean much.
posted by Nonsteroidal Anti-Inflammatory Drug at 7:37 AM on June 30, 2023 [10 favorites]
Here are two of the pictures taken with the Note20 Ultra.
Last answer, sorry I didn't sleep well so my thoughts are disorganized.
The Google web page says the first image is 1836 × 1868. At 400dpi that would be 4.59"x4.67". At 72dpi it would be 25.5"x25.95".
If they're trying to print the image at 25" square, then yes it will be low quality. If they just want 400dpi, then they should print it closer to 4.5" square.
posted by Nonsteroidal Anti-Inflammatory Drug at 7:40 AM on June 30, 2023 [3 favorites]
Last answer, sorry I didn't sleep well so my thoughts are disorganized.
The Google web page says the first image is 1836 × 1868. At 400dpi that would be 4.59"x4.67". At 72dpi it would be 25.5"x25.95".
If they're trying to print the image at 25" square, then yes it will be low quality. If they just want 400dpi, then they should print it closer to 4.5" square.
posted by Nonsteroidal Anti-Inflammatory Drug at 7:40 AM on June 30, 2023 [3 favorites]
400 (dots per inch, or pixels per inch) for a given picture will only be true at one specific size. As the picture size goes down, DPI goes up.
Looking at your first picture, it's about 1800 pixels high and wide. That's a low-resolution picture. At ~25" by 25", each inch has 72 pixels. At ~4.5" by 4.5", each inch has 400 pixels.
If you want to display it at 25" and 400 pixels per inch, your resolution needs to be about 10,000 pixels high and wide.
posted by Wilbefort at 7:43 AM on June 30, 2023 [2 favorites]
Looking at your first picture, it's about 1800 pixels high and wide. That's a low-resolution picture. At ~25" by 25", each inch has 72 pixels. At ~4.5" by 4.5", each inch has 400 pixels.
If you want to display it at 25" and 400 pixels per inch, your resolution needs to be about 10,000 pixels high and wide.
posted by Wilbefort at 7:43 AM on June 30, 2023 [2 favorites]
The purpose is to have a print-worthy photo.
Right, but at what size? The Samsung Note20 Ultra takes photos at 10 megapixels, so it's almost assuredly going to absolutely fine for anything 95% of people want to use it for in print.
The friend submitted the photos to the gallery requesting them and they're the ones saying they're only 72dpi. The gallery got submissions from many other artists in my friend's class and we're the only ones being told they the wrong dpi.
Do you absolutely, 100%, without a doubt, know that your friend and only your friend is getting told this by the gallery? Because it sounds like someone at the gallery doesn't know what they're doing or doesn't have some sort of layout software to place the photos in. No shame on the person or gallery, a lot of people make this mistake, particularly newer people when starting out.
A lot of times a gallery will ask for submissions in a specific format/way and when something even slightly different comes in, will bounce it back. I've seen countless instances of places asking for JPGs, then they get a TIFF and refuse to accept it because it's not the requested format, though the photo is technically fine for use. Ask your friend for the submission specs.
At first I thought it was maybe because they're on Google Photos...
Would not be surprised if someone at the gallery was pulling the low resolution screen versions, instead of downloading the high resolution originals.
posted by Brandon Blatcher at 7:49 AM on June 30, 2023 [1 favorite]
Right, but at what size? The Samsung Note20 Ultra takes photos at 10 megapixels, so it's almost assuredly going to absolutely fine for anything 95% of people want to use it for in print.
The friend submitted the photos to the gallery requesting them and they're the ones saying they're only 72dpi. The gallery got submissions from many other artists in my friend's class and we're the only ones being told they the wrong dpi.
Do you absolutely, 100%, without a doubt, know that your friend and only your friend is getting told this by the gallery? Because it sounds like someone at the gallery doesn't know what they're doing or doesn't have some sort of layout software to place the photos in. No shame on the person or gallery, a lot of people make this mistake, particularly newer people when starting out.
A lot of times a gallery will ask for submissions in a specific format/way and when something even slightly different comes in, will bounce it back. I've seen countless instances of places asking for JPGs, then they get a TIFF and refuse to accept it because it's not the requested format, though the photo is technically fine for use. Ask your friend for the submission specs.
At first I thought it was maybe because they're on Google Photos...
Would not be surprised if someone at the gallery was pulling the low resolution screen versions, instead of downloading the high resolution originals.
posted by Brandon Blatcher at 7:49 AM on June 30, 2023 [1 favorite]
DPI (dots per inch) is just the number of pixels divided by the size you want to print the image at.
DPI is meaningless without specifying a physical size in inches. You can ignore whatever DPI the software is telling you, because it can be changed easily -- the only thing that actually matters in the image file is the number of pixels.
You (or your friend) needs to find out from the gallery what physical size these images are intended to be printed at. Then multiply that by the DPI.
So, for example, if the images need to be printable 8 inches wide at 400 DPI, you need an image file which is 8 * 400 = 3200 pixels wide.
Or, alternatively, ask the gallery what is the minimum size in pixels for submissions.
posted by mekily at 8:03 AM on June 30, 2023 [5 favorites]
DPI is meaningless without specifying a physical size in inches. You can ignore whatever DPI the software is telling you, because it can be changed easily -- the only thing that actually matters in the image file is the number of pixels.
You (or your friend) needs to find out from the gallery what physical size these images are intended to be printed at. Then multiply that by the DPI.
So, for example, if the images need to be printable 8 inches wide at 400 DPI, you need an image file which is 8 * 400 = 3200 pixels wide.
Or, alternatively, ask the gallery what is the minimum size in pixels for submissions.
posted by mekily at 8:03 AM on June 30, 2023 [5 favorites]
Response by poster: I appreciate everyone's answers. Thank you.
When I look at the details of the photos on my phone, they are showing as larger.
For instance, for one of the photos in my link my phone is saying it's:
9.9MP, 3315 x 2986, 1.7MB.
Since the phone's camera is rated for 10MP, I'm assuming this is as high-quality as it can get (being 9.9). Presumably if I send these photos rather than the ones from Google Photos they will be acceptable, yes? I assume it's for a year-end photo-book of students' work so not printing enormous or anything.
And, regardless of my issue right now with these photos, how can I make sure that the camera on the phone is taking things, always, at the maximum resolution possible? Or does it just default to that?
posted by dobbs at 8:06 AM on June 30, 2023
When I look at the details of the photos on my phone, they are showing as larger.
For instance, for one of the photos in my link my phone is saying it's:
9.9MP, 3315 x 2986, 1.7MB.
Since the phone's camera is rated for 10MP, I'm assuming this is as high-quality as it can get (being 9.9). Presumably if I send these photos rather than the ones from Google Photos they will be acceptable, yes? I assume it's for a year-end photo-book of students' work so not printing enormous or anything.
And, regardless of my issue right now with these photos, how can I make sure that the camera on the phone is taking things, always, at the maximum resolution possible? Or does it just default to that?
posted by dobbs at 8:06 AM on June 30, 2023
You can divide your pixels by the DPI to get inches. So, 3315/400 gives you 8.2 inches, 2986/400 gives you 7.5 inches. Printing this photo at 400 DPI would yield a print that is 8.2 x 7.5 inches.
I'm not familiar with the Note20 Ultra but it looks like it exports at 12 megapixels by default (if this photo was cropped, that could account for the discrepancy with this particular image), but there is also a "4:3 108MP" mode in the aspect ratios section that captures 108 megapixel photos. These would be your highest-resolution images, but probably take up a significant amount of space.
posted by brentajones at 8:21 AM on June 30, 2023 [1 favorite]
I'm not familiar with the Note20 Ultra but it looks like it exports at 12 megapixels by default (if this photo was cropped, that could account for the discrepancy with this particular image), but there is also a "4:3 108MP" mode in the aspect ratios section that captures 108 megapixel photos. These would be your highest-resolution images, but probably take up a significant amount of space.
posted by brentajones at 8:21 AM on June 30, 2023 [1 favorite]
I should've also said that resolution is likely only achievable with the main camera (not the zoom lens), and it may not look better than the 12 MP image — many phones are doing something called "pixel-binning" which essentially means that on the 108MP sensor, some of the pixels can be grouped to act like one, with the idea being that that increases the quality of the final image (at the expense of resolution).
posted by brentajones at 8:27 AM on June 30, 2023
posted by brentajones at 8:27 AM on June 30, 2023
Presumably if I send these photos rather than the ones from Google Photos they will be acceptable, yes?
That's a safe assumption but they might still need to "resize" the physical dimensions down to get the image up to 400dpi.
Also what's tricky is that many email clients will resize images, so make sure you send it as a full-size attachment, not as an image inline with the text. It's possible the gallery or yearbook team have a way to upload files, which may be more straightforward to use.
posted by Nonsteroidal Anti-Inflammatory Drug at 9:17 AM on June 30, 2023 [1 favorite]
That's a safe assumption but they might still need to "resize" the physical dimensions down to get the image up to 400dpi.
Also what's tricky is that many email clients will resize images, so make sure you send it as a full-size attachment, not as an image inline with the text. It's possible the gallery or yearbook team have a way to upload files, which may be more straightforward to use.
posted by Nonsteroidal Anti-Inflammatory Drug at 9:17 AM on June 30, 2023 [1 favorite]
I think we're missing the fundamental question here.
How big is the print, and what DPI at that size are they asking for?
posted by kschang at 9:48 AM on June 30, 2023 [4 favorites]
How big is the print, and what DPI at that size are they asking for?
posted by kschang at 9:48 AM on June 30, 2023 [4 favorites]
If this stuff is going in a yearbook, I can say with certainty that whoever is complaining is confused or doesn't know what they're talking about. I used to print 8x10s from a camera with a 3008x2000 sensor (6MP) and they looked great, even with some cropping or flipping the aspect ratio
Perhaps not coffee table photo book you'd buy in a book store great, but plenty of detail and no issues with fuzziness.
posted by wierdo at 9:58 AM on June 30, 2023
Perhaps not coffee table photo book you'd buy in a book store great, but plenty of detail and no issues with fuzziness.
posted by wierdo at 9:58 AM on June 30, 2023
What kschang said - ask your friend for the direct specs from the gallery about either what the final print size is or minimum pixel dimensions for the photo to see if it's actually something your phone can do.
Are others shooting on a phone? Can you submit RAW photos? I think your phone might be able to do those if you aren't using filters.
https://www.makeuseof.com/how-to-shoot-raw-photos-samsung-galaxy/
posted by oneear at 10:04 AM on June 30, 2023 [1 favorite]
Are others shooting on a phone? Can you submit RAW photos? I think your phone might be able to do those if you aren't using filters.
https://www.makeuseof.com/how-to-shoot-raw-photos-samsung-galaxy/
posted by oneear at 10:04 AM on June 30, 2023 [1 favorite]
> 9.9MP, 3315 x 2986, 1.7MB.
Almost certainly if they receive this, they will be happy. If they receive something like the ones you linked above, which are more like 1269x1291 and 380KB, they will be pretty unhappy. That is indeed pretty small and low res for printing at any kind of size at all.
The 3315 x 2986, 1.7MB version will likely be plenty good for anything up to a full page of a yearbook (it comes out around 300dpi when printed as an 11x11 inch square, for example).
posted by flug at 2:40 PM on June 30, 2023
Almost certainly if they receive this, they will be happy. If they receive something like the ones you linked above, which are more like 1269x1291 and 380KB, they will be pretty unhappy. That is indeed pretty small and low res for printing at any kind of size at all.
The 3315 x 2986, 1.7MB version will likely be plenty good for anything up to a full page of a yearbook (it comes out around 300dpi when printed as an 11x11 inch square, for example).
posted by flug at 2:40 PM on June 30, 2023
This thread is closed to new comments.
posted by bowbeacon at 7:07 AM on June 30, 2023 [2 favorites]