What determines the size of your print?

[Iguanasan]

While the article JAS pointed to which states computer monitors are not actually 72 DPI is true, it is also very true that they are very close to it. The 72dpi or 96dpi is based only on one of the dimensions which I believe is the vertical dimension. So, most people will see your images in and around 75dpi, a few - very few - will have adjusted their monitors to 96dpi but that would be the exception rather than the norm.

Most people who are publishing for the web will ensure that they publish at 75dpi for the very reason you wish to do so.

[casil403]

WOW...I am surprised one can go that low.

[Iguanasan]

Compare for yourself:

300dpi


200dpi


96dpi


75dpi

[casil403]

PERFECT!! Iggy!

[Marko]

As far as i know.....DPI doesn't matter for the web. (unless you are posting full Jpeg files or very high res files that are ready for printing).

As far as i know, it's all about filesize for the web...because we DOWNGRADE our images (save as Jpeg, then we say what quality of jpeg) before posting them. (most of us anyway).

If I save an 800 pixel wide file at a medium Jpeg quality so that the end result is about 100-150K....that file will look bad (to me at least)when printed whether it was 300DPI or 72DPI.

DPI is mostly about printing. Pixels and filesize are the parameters for the web.

Just to reconfirm this, I printed 2 of Iggy's 81k files (one at 75 dpi and one at 300 dpi). Because the file was compressed to 81K, both versions look equally bad and i cannot tell which is 300 which is 75dpi.

[Iguanasan]

Hmmm.... Looks like I'm talking through my hat. I thought for sure DPI had some effect on the screen as well but now I'm thinking it only matters when you print. Been playing with different DPI settings here and it looks as though, for the screen, you see the image at about 75dpi, however, that has actually no impact whatsoever on the printing of the image. You can take the same image and print it at 20dpi or at 600dpi and it will effect the size on the paper, however, it doesn't effect the detail in the image.

So, it's about dimensions. If you give someone a full size 4000x3000 pixel image they have the capability to print a decent size at a reasonable high quality. If you only give them an 800x600 image then they are locked into an image which they can only print to a certain size. DPI information in the image is completely meaningless unless you print it.

Learn something new every day!

[Marko]

So, it's about dimensions. If you give someone a full size 4000x3000 pixel image they have the capability to print a decent size at a reasonable high quality. If you only give them an 800x600 image then they are locked into an image which they can only print to a certain size. DPI information in the image is completely meaningless unless you print it.

Learn something new every day!

For the web, again as far as I know - It's about dimensions AND filesize. If EITHER the 4000x3000 file OR the 800x600 is saved as 100% jpeg ( yielding LESS compression in the final file), you'll get respectable results if you try to print from it. Of course, those file sizes will be large. The 800 pixel file might be 700k to 1 meg, the 4000 file could be 15-20 megs. Some people DO INDEED upload in that quality for the express purpose of allowing people to print the photo. But for the purposes of protecting your work by uploading lower resolution files, don't worry about the DPI just save the file at a medium to lowish jpeg.

and I agree, DPI information in the image (for web use) is completely meaningless unless you print it. I do not believe I can see any difference in any of your 4 posted files Iggy. For the web, 81k is 81k when the dimensions of the file are identical.