Newbee with a question
Mar 31, 2017 21:01:38 #
Hi all, the better half asked me to take some shots of her quilt to be sent in for a contest. One of the requirements were that the pictures submitted be 1200 dpi. I am shooting with a Nikon D750 and checked the manual and cannot find where there is a setting for this, they come out as 300dpi. Can someone please enlighten me why they might require this 1200dpi and how to achieve it? Is there a camera setting I am missing or is this done in post?
Mar 31, 2017 21:08:31 #
Are you submitting prints? DPI refers to Dots Per Inch print resolution. 300 is pretty standard DPI for 8.5x11".
Mar 31, 2017 21:17:06 #
Thomas Firth wrote:
Hi all, the better half asked me to take some shots of her quilt to be sent in for a contest. One of the requirements were that the pictures submitted be 1200 dpi. I am shooting with a Nikon D750 and checked the manual and cannot find where there is a setting for this, they come out as 300dpi. Can someone please enlighten me why they might require this 1200dpi and how to achieve it? Is there a camera setting I am missing or is this done in post?
You are not missing anything, but whoever specified "1200dpi" is missing a lot!
That might make a smidgeon of sense of you are sending them a print. If it is a JPEG file, it's total nonsense.
They probably actually want a JPEG file that is at least 1200 pixels on the longest dimension. Hence it might be 1200x800 pixels. That is a very reasonable size for viewing on a computer screen.
The "300 dpi" resolution value from the images your camera produces means exactly nothing! It is an Exif tag, and when the image is viewed with a computer it is totally ignored. If printed the tag value might, or might not, be used to determine the physical size of a print. The tag value can easily be changed (with no serious effect), hence if you want to mess with their minds a little you can search out software that will write to the Exif data, and set it to the asked for 1200 dpi! No harm if they don't print it, but if they try that it could be dramatic...
Mar 31, 2017 21:25:53 #
With your D750 at 6000x4000 pixels, a 1200 dpi print would be approximately a 3x5 inches. 300 dpi is considered professional quality.
Apr 1, 2017 06:35:15 #
Thomas Firth wrote:
Hi all, the better half asked me to take some shots of her quilt to be sent in for a contest. One of the requirements were that the pictures submitted be 1200 dpi. I am shooting with a Nikon D750 and checked the manual and cannot find where there is a setting for this, they come out as 300dpi. Can someone please enlighten me why they might require this 1200dpi and how to achieve it? Is there a camera setting I am missing or is this done in post?
1200 dpi sounds pretty extreme. You will be printing these? DPI means dots-per-inch - as in printing. It couldn't be 1200 px, could it? 300 DPI is good enough the the Library of Congress. "...Apple claims that human vision is only capable of resolving 326 ppi (search online for their “Retina display” marketing materials). There is a lot of quibbling about that number but most still claim not more than 450 ppi"
https://blogs.loc.gov/thesignal/2013/07/you-say-you-want-a-resolution-how-many-dpippi-is-too-much/
Apr 1, 2017 08:24:33 #
My eyes when I was in my 20's could resolve better than 300dpi but not by much. The reason that I could see the individual dots that make up a print by the laser printer at 300dpi.
Apr 1, 2017 08:50:00 #
I agree with Apaflo, they probably want 1200 pixels on the long side. Not that it matters, but for one thing, you can't set DPI in your camera or Photoshop, only PPI (Pixels Per Inch) So if they are asking for DPI, they need to revise the requirement using the correct terms and give the more important information, pixel dimensions. I would ask someone there who knows to clarify what they really need. I've had to do that with several national publications that state only that "the images need to be 300DPI" Even if they said PPI, that's like telling someone to bake at 35O degrees.... How long?
Apr 1, 2017 09:57:08 #
Apr 1, 2017 10:09:13 #
gvarner
Loc: Central Oregon Coast
Thomas Firth wrote:
Hi all, the better half asked me to take some shots of her quilt to be sent in for a contest. One of the requirements were that the pictures submitted be 1200 dpi. I am shooting with a Nikon D750 and checked the manual and cannot find where there is a setting for this, they come out as 300dpi. Can someone please enlighten me why they might require this 1200dpi and how to achieve it? Is there a camera setting I am missing or is this done in post?
They have a typo, it's PPI and not DPI. They want a photo that is about 1200 PPI on the long side for viewing on a monitor. You can set this in your camera before the shot or resize in post processing on the computer if your software lets you do this. DPI is printer resolution. PPI is camera sensor reaolution.
Apr 1, 2017 10:09:37 #
peterg
Loc: Santa Rosa, CA
I've handled hundreds of quilt photos for quilt shows. I agree with others that dpi (dots/inch) means nothing. The number of pixels in the photos length/height is significant. Pictures with too many pixels eat up memory, but can easily be reduced. Photos with too few pixels cannot display the details needed to judge a quilt. I'm guessing that the judges want photos of about 1200 pixels on the long side.
Apr 1, 2017 11:24:42 #
Do not confuse DPI with PPI. DPI are pixels per inch for printing and as has been already said 300 DPI is the standard while PPI are pixels per inch in a print.
Apr 1, 2017 11:49:34 #
camerapapi wrote:
Do not confuse DPI with PPI. DPI are pixels per inch for printing and as has been already said 300 DPI is the standard while PPI are pixels per inch in a print.
Whoa, your intentions are noble but...
The tag in the JPEG file for resolution technically is "DPI", but that confuses everyone so it is most often now called PPI. DPI and PPI as used in the Exif data are precisely the same thing. The only place where DPI has a different meaning is in printer specifications where it refers to inkjet nozzle dots of ink, and it takes some multiple number of ink dots to form a pixel. Typically a photograph will be printed using perhaps 8 dots per pixel horizontally and vertically each, or a matrix of 64 dots per pixel. But the input image has pixels, while the print nozzles get a single command string that prints an entire line that has been dithered and is not divided into pixels.
The input file has pixels but the output relates only to inkjet nozzle dots. The relationship is fixed for any given print. Hence if we print at 300 PPI the printer might squirt 2400 ink dots per inch.
Apr 1, 2017 17:36:14 #
Thomas Firth wrote:
Hi all, the better half asked me to take some shots of her quilt to be sent in for a contest. One of the requirements were that the pictures submitted be 1200 dpi. I am shooting with a Nikon D750 and checked the manual and cannot find where there is a setting for this, they come out as 300dpi. Can someone please enlighten me why they might require this 1200dpi and how to achieve it? Is there a camera setting I am missing or is this done in post?
Hi Thomas,
First off the requirement is actually for something called "ppi," pixels per inch. Dots per inch (DPI) refers to a non-digital printing process. Photos from your camera come out at a predetermined size as specified by your camera manufacturer. Once you input the photo into a processing program you can export it at whatever size you need. The requirement for sizing is so that the file is small enough to be seen but not so small that it affects the quality of the viewing experience (so small enough to have some quality while decreasing the file size), this is normally required for digital input and viewing. Standard sizes for digital viewing range from about 700 ppi to 1500 ppi (normally set to the long side at export), at a resolution of 72, which is also standard for digital viewing. Each program exports differently so you will need to figure out how your processing program works.
Apr 1, 2017 18:16:54 #
via the lens wrote:
Hi Thomas, br br First off the requirement is act... (show quote)
Poppycock! Really! Try something to see. Use a program (exiftool is good) that lets you change the Exif tag, and make two copies of an image with different values for the Exif tag. Set one file to 10 and the other at 10000. You won't see any difference when viewing them.
Here are two example images to view. They have exactly the same number of pixels. The first has PPI set to 10, the second to 10000.
http://apaflo.com/misc/ppi_10.jpg
http://apaflo.com/misc/ppi_10000.jpg
Apr 1, 2017 19:58:38 #
Apaflo wrote:
Poppycock! Really! Try something to see. Use a ... (show quote)
How about Balderdash, you missed that one. So, is it all "Poppycock," or do you believe just a portion is "Poppycock." When I export a photo for a show it ends up being about 600k or maybe 700k, sometimes even less, versus my original file of 20-36MP. And that is what is needed for the web. Of course, someone could shoot a small jpeg in-camera, but then they could not control the specific size of the file. Perhaps I explained it inadequately, there is always that chance.
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