Have you ever gotten asked if your photos are high resolution or if your photos are a specific DPI? What do you say when you get a request that doesn't make sense?
When delivering photos to multiple different clients and venues, I regularly get asked if my photos are high-resolution or asked for a specific DPI. I've worked with print fairly extensively, but have been in the mostly screen end of things for the last few years. When people ask about high resolution, I tend to question why they are asking for high resolution and what high resolution means to them.
Maybe "high resolution" are trigger words for me. Most people dealing with files that are not photographers confuse the terms "high resolution," "DPI", "megapixels," and many others. It's the bane of my photographer life, you would think. I'm going to hopefully make this article a resource that people can reference if they need to when dealing with clients. If that doesn't work, at least it will be cathartic for me.
Bro, do you even high res?
DPI
Dots Per Inch. Think of this as the density of pixels within an image. I've heard people referencing a five-inch file, and to me, that is just an old way of saying I'm taking the file and using the total pixels to make a file that has a long edge of five inches. I find this useless, because we don't know what DPI this person is actually using or the total pixels in the image. Knowing and setting DPI is important for printing, but only then really.
You get high res! You get high res! and you get high res!
High Resolution
Listen. Most cameras these days are high resolution. You know highway billboards that are 50 feet wide? Those don't even use the full resolution of my Nikon Z 50 typically. In my experience, only gallery-quality mural prints actually require a real high-resolution camera. Print something six feet tall or wide, and if you want it to stand up to people putting their faces right in the image, then, yes, you may want a really nice medium format camera. Even then, I've seen D850 images blown up to 30 feet tall, and they still look great. Beyond this, every job I've done would be happy with D750 or Z 50 levels of resolution.
High resolution? Yes. Large amount of chromatic aberration? Also yes.
Megapixels
Megapixels? Really? Remember when they used to put the megapixel number on a sticker on the front of the camera, like fuel injection, or ABS on old cars? Despite the somewhat relegated term, megapixels actually offers some level of description of the image file that the previous two terms do not. Megapixels just means the total amount of pixels in your image. On my Z 50, 5,568px by 3,712px = 20,668,416, which is basically the 20.9 megapixels (million pixels) that this camera is rated at. But ultimately, who cares? Phones shoot more pixels than real cameras, but that doesn't make them better.
Photoshop's window of confusion for most people, the Image Size dialogue box.
Why None of the above Matters
Let's think about images like we are thinking about megapixels. Each image, either straight from the camera or sized and edited, has a pixel dimension. That could be 5,000px by 3,000px, or that could by 800px by 600px. With this pixel dimension, we instantly know how big the image is and if it satisfies our personal requirement for total resolution. If we make it a little simpler and just start referring to the long edge of the image, we can make this even simpler. It's like we have started measuring video resolution with 4K, FHD, etc. The measurement we are referring to is a single edge dimension. If we say we're delivering 5,000 px wide images, we know we can print these for most applications and they will serve as a high-resolution file. In the end, if the file you are delivering is destined for print, more than likely a photo editor or designer is altering and placing that photo anyways, so why bother with specifying DPI in the first place?
I believe the long-edge pixel dimension specification is the best way to describe and share image data. Now, it just needs a fancy name.
I get so sick of being ask, "are your photos high resolution?" Or, "do you shoot high resolution photos?" I just answer, "all my photos are high resolution." That seems to satisfy them.
hehe yup.
A bigger issue with resolution is that it isn't necessarily meaningful beyond a number - that is, resolution itself is not a measurement of resolving power. You can upscale any size file to any resolution you want, doesn't make it resolve more detail.
It's further complicated by things like camera shake, resolving ability of the lens, diffraction, lens aberrations, or the type of sensor - a monochrome sensor may have 24MP but will out-resolve a 36MP bayer sensor if both are shot under optimal conditions. Foveon technology presents the same issue.
Totally right - my article doesn't even begin to cover any of that stuff. I think many peoples' brains will explode if we went the route of over-explanation to our clients.
Yup. It's a fools errand to explain to clients. I often upscale to match resolutions if, say, I use two different cameras on a job with different resolutions. Has literally never been noticed or an issue. In terms of linear resolution, the difference is already not as much as people think (20% linear increase from the Z6 to D810, for example).
I regularly print my work anywhere from 8x10 up to 16x24, 17x22, etc. I think people would be surprised how large you can print a good 12MP D700 file that holds up pretty nicely even under closer viewing distances that would be normal.
Sometimes the best thing to do is over explain it. That way they get bored and never ask again.
Yes, had a textbook publisher that needed wildlife photos at 300 DPI. They wouldn't trust me when I told them the very high resolution photos would be more than 300 DPI and that would be fine. They didn't know what size they were going to be printed at and didn't understand why I needed to know that to provide them pictures at exactly 300 DPI.
I just ask them what they intend to do with the image, most people asking a 2mb file or need 300dpi don't really know what they mean. But that formula worked last time.
In my experience that is exactly the case - the photographers are the most knowledgeable on this topic. Trust us!
Asking for 300dpi is like asking for an image measured in 'inches' or 'centimeters' without saying how many.
Mine will go up to 29,999 dpi resolution. Well at least in Photoshop I can change it to that. I haven't tried other programs yet :-)
It's not surprising that people would be confused about this.
The Image Size window in Photoshop may tell you the pixel dimensions are 5760 x 3840, but if that JPEG came out of a Canon 5D3, it'll say 72 PPI in the box marked "Resolution." I've had several clients complain that they received low resolution images. One time it was a graphic designer saying this, I figured he would have known better.
Any of us that understand these concepts will just have to be patient if we need to explain it to someone.
Or consult my article :0
Oops. I read your article but missed the picture of the Image Size dialog. Thank you for a nice article, by the way.
This article raises an important point, thanks, but please make sure your terminology is correct. It's PPI not DPI when it comes to image resolution. DPI is only for printing output and does not translate because the actual ink drops overlap in sophisticated ways. Pixels per Inch is the correct term and should not be used interchangeably with Dot per Inch - this contributes greatly to the confusion your article aims to 'resolve' ;-)
Exactly, I always used PPI to determine how large an image would look on a given screen and DPI was used for printing. Unfortunately, DPI has caught on as the "catch phrase" to describe a lot of things it isn't.
You're exactly right and I considered adding a plethora of more accurate terms but chose to use the ones that I've heard professionals use. On top of that, PPI is exactly as useless in describing an image as DPI is. We don't know the total amount of pixels in the image and ultimately this is what people are after.
Have you been asked if your photos are high resolution or if your photos are a specific DPI?
That’s better.
Answer: No.
The real question should be not whether one uses a high-resolution sensor, but whether the images one makes are in optimal focus. You can have the best lens / sensor combo in the world, but if you can’t hold it steady enough or if one shoots a subject too quickly, the value of the lens is not being used. Especially for a scene that can be studied and perfected. Auto focus does fail. My greatest disappointment is pixel peaking a lack of clarity. In reference to this ‘cathartic essay‘, if one is not printing their work, and it is seen only on screen, then perfect focus may not be an issue. But it should be. So it should always be the pros role to deliver the best possible work regardless of the terms used to describe a measure of quality.
I like when you get a great shot and folks say ‘You must have a good camera’. ;-0)
I'm afraid the constant misuse of the "dpi" suffix makes this pretty pointless.
Haven't been asked if my images are high res but have been asked some even dumber questions like... We need it to be 20cm long edge (without ppi), We need the file to be 2Mb (where do you even start?), we need the file at 300 ppi (but no dimensions) and, can you convert it to CMYK for us, when we did it, it came out weird.
lol at asking for a specific number of mb... how do you even do that aside from trial and error?
Converting to CMYK I understand though, if they intend to print it.
CMYK needs to be done using the profile of the Printer / paper / ink etc. If the client doesn't understand that then what chance do I have? Best left to the Print house.
That's fair - I don't convert to CMYK when I print personally. I've found better results keeping in RGB and using the ICC profiles and tweaking.
DPI is the stupidest measure in the world today. I have clients that would rather get a 640x480 image at 300 DPI than a 9000x6000 image at 72 DPI, because 300 DPI is "better." Since my Canons shoot at 72 DPI, I run them through a batch program to convert the EXIF to 300 DPI at no change in resolution before shipping them out. My clients are thrilled, and it saves me from having secretaries sending me emails schooling me on resolution. Sigh.
Sorry Grant, DPI is not "density of pixels within an image", that's PPI, Pixels Per Inch. DPI, Dots Per Inch, is a printer setting for how dense the dots will be on your PRINTED image. DPI is only relevant when you're handing someone a print. (But Geek-on!) :-)
Right - and I commented on someone else's version of your comment - but literally no one I have talked to in my professional life has ever mentioned PPI to me. They have however misused DPI or talk about it in reference to printing when printing was never part of the goal. The point is it's all quite confusing and I think we should move to only talk about total pixels in an image.