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Hey Bennett its JT from NBC expedition. Is there any way to get a good photo pf my drone in the cave that you took?
This article keeps referring to DPI where in many cases it means PPI. So, although it is correct in many ways, it ends up adding to the the confusion and misunderstanding it was intended to clear up.
Pixels per inch (PPI) are what is input to the printer. Dots per inch (DPI) are what the printer puts on the paper. With typical inputs ranging from lower than 100 PPI to a high of 600 PPI modern inkjet printers typically print several dots for each pixel.
It is the pixel density (PPI not DPI) that sets an upper limit to the amount of genuine detail in the printed image. [Whether that limit is reached depends on how much detail was actually captured by the lens and the photographer’s technique. But regardless of the number of pixels available it is the amount of genuine detail in the image that determines how large it can be satisfactorily printed. The less genuine detail in the image the more PPI are needed to produce a print that will look good from close up. Whether all the available detail appears in the final print then depends on how the printer’s software and available inks maps pixels to coloured dots, and the paper on which the print is being made].
As for what the PPI should be, the figure of 300 is bandied about on the net as the maximum resolution that most people can distinguish from close up. [i.e. any more pixels would be wasted, as the eyes are incapable of seeing the extra detail] and, therefore, as an ideal to be aimed for.
This is nonsense, but that has not prevented it from being repeated al over the internet, and in many cases i is obviously by people that are uncritically repeating what they have heard, with little or no hands-on experience.
So the number of pixels does not determine the amount of detail in the photo. It is merely an upper limit. If the lens is delivering less data than the sensor is capable of capturing then the pixels capture the data with fewer artefacts, but they do not add any data. And if the scene itself is lacking in detail the best lens and a sensor with lots of pixels cannot add more detail.
Also, making a good print at fewer than 300 PPI is not, as the self-professed experts would have you think, just about the viewing distance. The content of the image makes a difference. Some images look as good as they are ever going to at 100 PPI. Others may even need more than 300 PPI if they are going to stand up to examination from 5 or 6 inches away.
And there are yet more variables. A printer with a 12 ink system is going to give better tonal gradation than the typical 4 ink desktop printer, and a glossy coated paper is going to show up insufficient pixels at higher densities than a rough surfaced “Art” paper.
A lot of skill, knowledge and experience goes into making a stunning digital print. The internet promotes the idea that we can all produce wonderful prints just by following a simplistic rules (print at 300 DPI … whoops … PPI …. or look up the “correct” PPI for the intended viewing distance). It just isn’t so. These are no more than hints at what might be a good starting point to figure out how big you can print with the pixels at your disposal. But the realities of the art of printing are more complex and subtle.
Hi, Tom! I agree with just about everything you said.
Yes, I do use DPI when PPI would be more appropriate, but that was intentional. Most layout and image editing software refers to that arbitrary metadata setting as DPI (although recently Photoshop has started calling this “Resolution”). My target audience was all those people who get confused by this DPI setting and post online asking what they should set it to, followed by a lot of misinformation just like you said. Plus, there’s a particular magazine editor who long ago somehow drastically reduced the resolution of one my photos, went to press with the low-res version on a full two-page spread, and then tried to blame me because “my image’s DPI wasn’t set right.” (Ultimately, she apologized.)
As you mentioned, there’s a lot more to both capturing and printing an image. Naturally, a better lens is going to capture a better photo; a better printer is going to produce a better print. All of these are outside the scope of this article, and frankly irrelevant to a photo’s DPI metadata setting.
The point is exactly what you said and I mentioned several times—detail. A 5000×4000 photo is going to have more detail than the same photo at 500×400 (assuming you didn’t just make the 500×400 larger). 😉 That internal DPI metadata doesn’t add or remove detail but changing pixel count does, as shown by my comparisons above.
By the way, there is scientific basis to resolution vs. viewing distance. Granted, most of the “self-professed experts” online are just regurgitating forum posts. However, I actually have read quite a few scientific studies on the subject. I linked the most relevant one in my article. If you have a study that shows these numbers are nonsense, I’d love to read it and possibly reference it in my article.
Thanks for the cool and informative article. Love it.
But I have a question which I have tried to search online for hours and yet to have a responds. So I am hoping you could help.
I’m using Panasonic G7 which is 16MP. Taking one of the pictures that I have for example. After editing, the properties from the picture are:
Dimension: 4208 x 3464
Width: 4208 pixel
Height: 3464 pixel
Horizontal resolution: 300 dpi
Vertical resolution 300 dpi
File size: 8.86 MB
After putting in my Signature (watermark), it reads:
Dimension: 4208 x 3464
Width: 4208 pixel
Height: 3464 pixel
Horizontal resolution: 96 dpi
Vertical resolution 96 dpi
File size: 1.35 MB
So both of the pictures have identical pixel counts but the dpi are different. Will I get a lower quality photo print for the picture with lower dpi?
How did you make your picture to have different dpi but same file size? I thought dpi are the amount of (color) information of the picture and the more dpi there is, the bigger file size it will be.
Thanks for your advice. 🙂
Hi, Edward. The DPI won’t affect anything here. Dimensions are the same. However, your images are dropping from 8.86 MB down to 1.35 MB, thus your software is reducing the JPEG quality. It’s so low that you will probably see “artifacts”, which are blocky areas in the compressed photos. I didn’t cover JPEG quality in this article; that’s a whole other subject, but I’ll provide some pointers here. You don’t mention what software you’re using to add the watermark, but likely it will have a JPEG compression setting somewhere when you save or export the image. The higher the percentage, the better the quality, but the larger the MB. Usually, 40–60% is a good compromise for web images; 80% is good for prints. Personally, I use 85% for my photos. I picked that after extensive comparisons of my original RAW to various percentages. I found that the common 80% still produced some very minor artifacts, but at 85% there were virtually none, and anything higher just increased my file sizes with no discernible visual difference. YMMV.
Thanks for reply. I’m using some freeware that I found online to do a mass watermarking on my pictures.
So, the dropping in size does affect the print quality. Hmmm… do you have any recommendation on which software should I use to watermark my photo which will not affect the print quality?
Once again thanks for taking time to reply me. 🙂 Greatly appreciated.
Thanks for your reply.
I’m using uMark for the watermarking and also I have tired converting it to JPG with 100% quality retention, but still my picture’s size decreased from 7.11MB to 4.28MB.
Is there anyway/recommendation on what I should do; or which software I should use so I could retain the quality and size of my picture? Thanks.
Looking at this a little closer, the Panasonic G7 supports RAW. Thus, I assume your original 8MB photos at 16MP are shot in RAW. That’s great! I recommend always shooting in RAW so you get the actual sensor data. That allows superior color correction, post-processing, etc.
That said, uMark is likely doing fine with its compression. No need to change your watermarking software.
Also, as I said earlier, 80-85% quality is good for JPEGs. It’s what I use for all my printed photos. However, note that JPEGs are always “lossy” (loses image quality/data), even at 100%. This is fine for photos. However, if you want absolutely no data loss, use a lossless format like PNG or TIFF (lossless formats are preferred for things like line art and logos).
Thanks for your reply again. Have a good day and weekend! Please keep up the good work (in making contents like this)!
I recently had some old film processed. The scans returned to me are 72 dpi and appx. 2000×3000 pixels. The service charges a fee to get your images returned on a disc at 300 dpi. I downloaded and saved these 72 dpi scans. If I plan to print these images in the future should I get the extra disc or does it matter?
Like title of the article indicates, DPI doesn’t matter. There is no benefit to getting the same resolution at 300 DPI. The only reason to pay the service fee is if the *scanned* resolution is greater than 2000×3000. E.g., the scans are actually 4000×6000, and it costs extra to get this larger resolution, otherwise they reduce it to 2000×3000.
As an example, one of my cameras is a Canon 1D Mark IV (16px) which I shoot at Large Jpeg 4896 x 3264 @ 72dpi. I do all my editing at this original size on a duplicate keeping the original image unedited. Upon finalization of the edit on this duplicate I usually will make two more duplicates, one of which I will size to 300dpi for print @ 9 x 13.5in, the other i would downsize the image to 9x 13.5in @ 72dpi. Am I doing this correctly? I do the same with my 5D Mark II Full Frame. I noticed a photog sent me his original image for editing, shot on a Nikon, NEF file, and the dpi was 300dpi. Do you think this is a standard setting for a NEF file? I actually had some difficulty cleaning and editing his images, they were not sharp. I edit in Adobe Photoshop CC, Lightroom Classic and Affinity. I do want to hurt his feelings nor look foolish when I need to bring this subject up. Thanks
I’m sorry for the delay in replying.
You don’t need to make multiple copies with different DPIs. As my article states, DPI is an arbitrary metadata setting. The only thing that matters in terms of resolution is pixels. Ignore the DPI and keep the pixels at their original maximum (e.g., 4896 x 3264 pixels). The only time I change my resolution is cropping or when I need a lower resolution version for something like a web page. My Canon tags its RAW files at 240 DPI. I have never changed it because it doesn’t matter.
As for your photographer’s NEF files, as long as you haven’t been tinkering with DPI or resolution after importing, the NEF is going to be the best original version you can get. I can’t comment further without knowing a little more. Maybe the photographer had a bad day. Maybe the autofocus was off. Tough subject to shoot. Tough location. I can understand all of that. As a cave photographer, my lens and camera regularly fog up, get covered with dust, splashed with water, smeared with mud, blindly shooting from angles where I physically can’t position my body. Regardless, the DPI setting has absolutely NO affect on photo clarity, so that’s not the issue.
I am shocked at your attacks on Grary. I have known him and Sue over 30 years and consider them to be the finest people I know in the caving commu.ity or elsewhere. Your vitriolic attacks say much more about you than Geary. The extremes you have gone to to slam him are quite impressive. I don’t doubt that all who know him well think all this is garbage. I certainly do.
So, Mary, you’ve been friends with Geary for 20 years. I was his friend for 7 years. We did all kinds of things together. One of the best stories I ever wrote was published in the NSS News, May 2015, and it revolved around Geary and the amusing situations in which we found ourselves on a cave trip. I was his friend. He was my friend. But all that changed when Geary and Sue started accusing us of misappropriation of funds.
Geary didn’t stop with just making accusations. He got attorneys involved. Then he went around told people we were misappropriating funds. Geary had Rob Bisset over to his house and told him we were misappropriating funds. He called Allan Cobb and told him we were misappropriating funds. He sent an email to me, Rob Bisset, Gregg Williams, and Pam Campbell describing all the ways that we were misappropriating funds. And those are just some of the ones that I currently know about.
I have included Geary’s email in the Misappropriation document above ( https://bennettlee.com/wp-content/uploads/3-Misappropriation.pdf). In it, Geary explicitly states “…to claim that the profits for the event are the grotto’s is a misappropriation of funds. I obtained an opinion from the NSS legal Committee on this (Jay Clark) and have a second legal opinion pending from Pre-Paid Legal as confirmation.” That’s just two sentences out of a four-page email where Geary makes multiple claims that we misappropriated funds. I proved every one of Geary’s accusations were lies. Our Grotto did NOT misappropriate funds. Geary’s own attorney, Jay Clark from the NSS Legal Committee, couldn’t substantiate Geary’s claims. Ted Lee, also from the NSS Legal Committee, finally convinced Geary that his claims were false.
What is your defense for Geary? You’ve known him 20 years, therefore everything I have posted here is “garbage”? Multiple witnesses, Geary’s own emails, statement from Geary’s own attorney–all lies? If that’s your defense, then your head is so far up Geary’s ass that the only thing you can see is the shit that Geary is feeding you.
Pull your head out of Geary’s ass. Don’t believe him. Don’t believe me. DO YOUR OWN RESEARCH. Contact those people who I listed above. Ask Rob Bisset if he was at Geary’s house where Geary told him the Grotto is misappropriating funds. Ask Allan Cobb if Geary called him and told him the same thing. Ask Rob Bisset, Gregg Williams, and Pam Campbell if the email that I included with all of Geary’s accusations is genuine. Their emails are in the header of Geary’s email. But if you want to make sure I didn’t alter those, all these people are or were NSS members. Look up their contact information in the NSS Members Manual. (Note that Pam and I are no longer renewing our NSS membership nor supporting the NSS while Geary is its President, so you’ll have to lookup her in an older manual.)
I personally challenge you, Mary, to do this research. And if you truly believe that what I’ve posted here is garbage, then your research should vindicate Geary. Then come back here and defend him with actual facts rather than just calling me a liar because you’ve known Geary for 20 years.
However, if you come to the inevitable conclusion that yes, Geary did falsely accuse our Grotto of misappropriation of funds, then what would your recommendations be to your friend of 20 years? What should Geary do to rectify this situation?
Think about that, Mary. Geary comes to you and says that he has just falsely accused his friends of misappropriation of funds, and asks you what should he do about? I hope your response isn’t, “Fuck ’em. Everything they say is garbage.” Instead, I would hope your response would be, “Well, Geary, admit that you were wrong and apologize.” That is exactly what I have been waiting for…an apology.
After Geary made his accusations, I consulted Jay Clark and Ted Lee, both from the NSS Legal Committee, and they both sided with me that the Bexar Grotto did NOT misappropriate funds. Geary KNEW he was wrong at this point. What should he do now, Mary? What would you recommend? Geary knows that he is wrong, but instead of apologizing, he hid the fact that behind the scenes he had been falsely accusing our Grotto of misappropriation of funds and lied to the Grotto in the faces of the very people to whom he should have been apologizing.
Wow. What’s your defense to that, Mary?
I sat on this for months. And when it became clear that Geary would never come clean, and our Grotto would never know about Geary’s attacks against us, I chose to publish his email with all of its threats and accusations, along with 32 pages of proof that Geary’s accusations were false.
Now Geary is exposed with his own words proving that Geary accused us of misappropriation of funds, along with my research and statements from multiple attorneys–including Geary’s own attorney–saying we did not misappropriate funds. What should he do now, Mary? Come clean? Admit he was wrong and apologize for falsely accusing his friends of misappropriation of funds? Again, instead of apologizing, Geary made jokes and attacked me personally, calling me a liar. Read his email up above. I don’t think falsely accusing your friends of a felony crime is a joking matter. Do you, Mary? Do you think it’s appropriate for Geary to joke about it?
I am going to reiterate my challenge to you Mary. Do your own research. Don’t believe me. Don’t believe Geary. Contact the other witnesses to Geary’s accusations. Then come back here defend Geary with actual facts, or maybe you’ll be back with an apology of your own. “I’m sorry, Bennett. Turns out you were right. Geary absolutely did falsely accuse you and your Grotto officers of misappropriation of funds. He was wrong. He should apologize.”
I look forward to your response. I hope next time it is based on actual facts instead of attacking me personally and calling my work garbage simply because you are Geary’s friend.
Wow, Bennett, those are amazing photographs! The names you guys have given to these features are imaginative, too.
Hi Bennett – You should enter this in the 2020 NSS Video Salon! Contact me if you have questions about entering.
Not a chance in Hell that I’m going to support the NSS while Geary Schindel is its President and using the NSS legal committee to try to threaten and bully the Bexar Grotto. See https://bennettlee.com/caving/geary/ if you want to know more.
Super-awesome presentation and pictures, Bennett!
awesome display of knowledge
Hi all. This is all about photography which is an image that has a lot of built-in information. Does this same concept apply to graphic design where you start with a blank canvas and add the content, be it a single pixel or millions of pixels? Even if it does, is it not best practice to create anything for print at a minimum of 300 ppi if it is not vector?
Yes, you’re absolutely right. This article is about images with a fixed number of pixels, like photographs. In contrast, vectors, such as artwork created in Adobe Illustrator, are entirely different. Vectors are mathematical formulas that describe shapes. When you rasterize vectors (e.g., export to JPEG/PNG or print), you are converting these formulas to blocky pixels. At this point, you need to know your target output, like printing a 1×1 inch logo on a business card. I agree with you that the minimum in this circumstance should be 300 DPI, which gives you a 300×300 pixel image. But what if the vector art is going on a 40×12 foot highway billboard? That’s where viewing distance comes into play. My table above doesn’t list billboards, but 300 DPI is definitely overkill for that.
Ideally, you want to leave your vectors as vectors. Embed the actual vector in your documents instead of a blocky rasterized image. Send the vector file to your printshop. That way vectors stay in their ideal mathematical representation right up until the time of printing when its target DPI gets negotiated between the vector application and the target printer.
However, if you do decide output your vectors to a rasterized image, by definition you are now dealing with a fixed number of pixels. Hence, this article applies and DPI no longer matters. (What’s unique with vectors is that if you need more pixels, you just export again with a larger resolution, which is not possible with the bat photo examples above. Even so, all these outputs are ultimately still a fixed number of pixels.)
Great artice Bennett. Thanks for all your effort to explain. My question is if I shoot raw and the image arrives in photoshop as 300 dpi and i cut the dpi to 150to get more pixels hence a larger printed image have I lost half the resoulution detail?
Thank you for your reply, Edward McHugh
Just be sure that the resolution (width and height) stay the same. Unfortunately, when you cut the DPI from 300 to 150, Photoshop will automatically cut the resolution in half, too (e.g., from 4000×3000 to 2000×1500). To fix, first copy one of the original resolution settings (e.g., 4000), then change the DPI, and finally paste the original resolution setting back (the other resolution setting will automatically reset).
By the way, a few days ago I would have said that you shouldn’t need to touch the DPI in Photoshop at all. However, just this past weekend I ran into a problem combining images with different DPIs directly into Acrobat. Page sizes were different based on the image’ embedded DPI. (One of the only instances in which DPI still matters–calculating page size given a DPI and specific number of pixels.) I could have tweaked page sizes in each document, but easiest fix for me was to change the DPIs in Photoshop and Lightroom before combining into Acrobat.