DPI vs file size

[TownCryer]

I had a paid for photos and got a CD of the photos with file sizes of 300k average size. I was told by the photographer when asked about the small size of the files that the DIP was high and the final photo is not effected by the size of the file and these 300k files will enlarge without deteriorating. He used a nikon camera of pro quality. Thanks for your replys.

[CharminEyes]

What is important and often overlooked is that DPI is only one of the two items that need to be understood. The other is the image size. Talking about DPI without also talking about image size is rather useless. Think of a photo 1" x 1" from a file that has 300 DPI (great), and then that same photo from that same file that is 300" x 300", and it will have only 1 DPI (terrible). Too keep DPI constant, the file size goes up rapidly as the size of the image increases.

So, when you talk about DPI, you have to also ask about the picture size. The file size is proporational to the DPI times the square inches of the image (DPI times height times width).

Please PM me if this is about as clear as mud and I'll try to explain it in a way that is easier to understand, plus help you got from where you are to where you want to be.

[thx]

Sorry, I think you got ripped off. It will depend on the OS, but usually you can right-click on the image file (my guess you have jpg), and display properties. It may display the resolution. It may also say how low your compression was on your pic.
A pro should give you files in multiple formats... one for casual posting (say thumbnail 400x300), and higher resolutions (4k x 3k... or more) with little compression. (large file sizes).

Try this.. How much can you zoom in on a picture? If you size it for a 8 by 11 printout (on paper), is it acceptable to you? Or can you see too many square pixels

If you never need to printout the pictures, zoom in, or do anything serious with them, then, perhaps, you are fine.

[jframe2]

I think your photographer definitely gave you poor service and agree with thx that you should have received the images in multiple output sizes.

Some other points-
- do not rely on your monitor as to what the printed pic will look like, unless you have a professionally calibrated monitor;
- if your output size will be 4x6 (the usual print size from a Wal-Mart, or Wall-Greens, etc) you will probably be fine.
Jframe2

[Guest061019]

Wait a min here fellas. What charmineyes is correct. He forgot one more point to consider. JPG compression. If the files were compressed to say a factor of 5, the end images could appear to be 300k in the finder or info window but still be of sufficient print quality. Not for a huge 16x20 print but probably a 5x7 or 4x6. Here is an example. I took an image file of 18 mb in photo shop. The dimensions were 10 x 6.66 at 300 dpi. I saved at jpg compression 85%. The end file size in the finder was 795k. The same file was saved at compression 55% the end file size was 303k.

I'm not saying the photographer didn't.t give you low res files.... I don't know... But, there are lots f factors in play here. The best thing you can do is first educate your self just a bit about image file size. The second is Call the photographer and ask them what they did and how big the files are. You need to know what you need befor you ask for high resolution files. .
Here is a quick link that might help.
http://www.microscope-microscope.org...resolution.htm

http://www.photoshopessentials.com/e...resolution.php

Good luck man! I hope it al works out for you!

[Guest061918]

Open them in Photoshop and change the image size.

[abcxyz]

for online advertisements you only need 72dpi, which you can easily create with 300dpi files and run em through photoshop, after you change the dpi THEN you can adjust the image size down to acceptable screen dimensions, but the 300dpi files you have should be sized correctly with appropriate dpi for print, so keep the originals just make some lower resolution copies (72dpi) for online adds, and dont worry you didnt get ripped off

[whshark]

It depends on the size of print you wish to make later on. My 12Mp olympus DSLR usually generates 4~5MB jpeg pictures with which you can print easily as big as 20x20. I think with 300k, you can print 8x10 at most later on.

[thx]

The professional photographer should also be giving the client a copy of the original files. Even, if he is using RAW files. Well, ok, most people will not need those huge files, but, burning them a few data DVDs will be more valuable to them in the long run.
Do not give them the 'dumbed down' versions only.

However, I have seen some digital photographers that will give the client a different price depending on the output quality. (example: $x for screen display, $xx for print quality, $xxx for portfolio)