LoriB

For printing purposes, I was told that if I resize a file that I should change the dpi to 300. If I leave the file as it is (straight out of the camera) then leave the dpi alone.
For instance SOOC file is 2212x3318 w/72 dpi. If I wanted to resize it say to 683x1024 then I should change the dpi to 300. Is this correct? Thanks in advance for your help!

MT Shooter Loc: Montana

You are totally confusing "DPI" and "PPI".
PPI is Pixels Per Inch and refers to digital sensors and how many light-sensing pixels are placed on its surface.
DPI is Dots Per Inch and is a printing term denoting how many dots of ink per lineal inch that particular printer will lay down in making a print.

LoriB

Well I am quoting what my camera says the file size is and the camera says the file in pixels is 2212x3318 and dpi is 72. I want to give the file to someone, they may want to go get it printed in 11x14. I want to know if I should leave the file and dpi as it is or should I resize it? and If I resize it, should I change the dpi to 300.

TheDman Loc: USA

I wouldn't worry about the DPI (ppi) if they're going to print it 11x14 regardless. I would just give them the maximum file size. However, you're going to have to crop it, since 2212x3318 doesn't fit an 11x14 aspect ratio. So I would crop it to match 11x14 and save it at maximum quality.

Bobspez Loc: Southern NJ, USA

I would leave it as is. Any resizing will likely lose resolution. It may or may not show on the print, but why take a chance.

How do you reset the dpi when you change a file size (just curious as I hadn't heard of being able to do that).

Bob

LoriB

I have Photoshop Elements and if you go to Image>resize>, then it shows the dimensions of the photo and the resolution. You can change the resolution there to 300.

GoofyNewfie Loc: Kansas City

That's 300 ppi.
From the FAQ section regarding PPI & DPI: link

As others have said, I would leave it as-is.
The total pixels are what is important, though your file is too small to go to 11 x 14 @ 300ppi without some pixel pushing.
You probably won't see any difference if you used 200 ppi, which is within the resolution of your camera.
If you do see a difference, you're too close and using a magnifying glass.

LoriB

Thank you all very much!

b.dehautdessert

Well, since I do this for a living, 72 DPI is going to look terrible if you leave it that way and it's printed. 300 DPI (not pixels, dots!) is going to give you a great print at 11 x 14 and yes you are going to have to resize it to those dimensions.

265 or 280 DPI is roughly "photo quality" as far as the average human eye can see. 300 gives you an extra margin so why not use it? Personally, and I *swear* I can see the difference, when I'm really going for super resolution I jump it to 350 DPI but it's really not necessary. I'm a resolution freak, I admit it.

If you want an easy comparison, look at the DPI comparisons of resolution on high quality computer tablets like Apple's latest Retina display, or the Nexus, or the Fire HDX. Those screens are incredibly crisp, and they all run at around 300-350 DPI. Forget the pixel numbers. Look at the dots per inch. That's what counts in the end.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

The printer's native resolution is the critical thing to look at. The next thing is the size of the final print which is tied to viewing distance.

An Epson 4880 for instance has a native resolution of 720 dpi. Choosing a print resolution of a multiple of that number - 180, 260, 720 etc will yield better image quality than selecting 240, 300, 400 etc.

An 11x14 print only needs to be printed at 156 ppi assuming a normal viewing distance of 27". So, if this were being printed on an Epson, I would select 180 dpi. If you multiply the longest dimension by the dpi, you will get the number of pixels you need - in this case your image must have 2520 pixels on its longest side. (180x14).

Selecting a print resolution that is higher than what is necessary is not going to result in a sharper print at normal viewing distances - the eye simply cannot resolve the fine detail. So you end up with much larger image files and much slower printing.

This is a very well thought out discussion and reference that explains the connection between eyes, print resultion and pixel dimensions on an image

http://www.photokaboom.com/photography/learn/printing/resolution/1_which_resolution_print_size_viewing_distance.htm

mldavis2

Let me make a suggestion here if you are not using your own printer.

If you are only sending in one image for printing, especially a large print of 11x14 or larger, send the original image after your edits and crops. Make sure you crop to the same aspect ratio as the desired output print since most of the common sizes are not the same as your sensor. 5x7, 8x10 and 11x14 are all different ratios and if you let the printer crop the image, you may lose some edge detail that gets cut off to make it fit. Crop as an "unrestrained" crop with the appropriate aspect ratio but do not change the ppi density.

Second, unless you know the resolution in ppi (not dpi) of the printer being used, their RIP (Raster Image Processor) will change your carefully edited ppi to one that the printer uses. Every time you alter the ppi density of the image, you are relying on your editor program to make decisions about what algorithm to use to most effectively resize the pixel information. You, or your image editor, must choose between choices such as bicubic, bilinear, nearest neighbor, etc. (there are six choices in Photoshop). If you resize the image to 300 ppi and the printer uses a 240 ppi output, the image will have been resized twice with resultant degradation of the image each time it is manipulated. The larger the print, the more important this becomes, but you get the point.

The downside here is that if you do some critical sharpening, you will lose some of that effect with any resizing. So the best choice would be to find out what resolution your printer uses and crop/resize to that exact ppi.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Best solution is to spend $70 and purchase Qimage Ultimate - it is a printing utility that accepts an image at any resolution and creates a print that is optimized for the specific printer and its native dpi. It will print the best looking print as long as you are in the ballpark - ie, not trying to print a 1024x700 image to 24x36. The image is properly resampled, anti-aliasing and output sharpening is applied (maximum possible without halos). The results are better than just about anything you can do with Photoshop and a calculator. Only thing better is a RIP (raster image processor) - the best $70 you can spend besides ink for your printer.

mldavis2

Thanks, @Gene51. We're on different pages here.

I went through three inkjet printers (and many at work) before throwing them all out due to excessive ink costs. If you don't use an inkjet printer every day or two, the ink dries out in the nozzles and you use more ink during the cleaning cycles than in printing. And ink is frightfully expensive if you do much printing at all compared to commercial labs. I now use laser printers exclusively for B&W and send my serious prints to MPix.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

ML - I was on that page, but moved on. Qimage looks at the printer, then selects the optimum image settings. The result is visibly better. I have been a photoshop user since 2000, and my printing issues ended in 2008 when I got my first copy of Qimage. I print on an Epson 4880 and an HP Z3200, and would never waste the time to do the calculations required when printing from Photoshop.

Mark7829 Loc: Calfornia

Is the file JPEG out of the camera?