DPI Determines Resolution, Not Quality
There’s many web pages about DPI that give somewhat ambiguous and over-loaded bloated text about the topic. I found a few (more) that give clear, concise and accurate information. I hope you enjoy reading as much as I did – and discover all about DPI!
- Here is a great article about resolution that talks about how to determine if you have adequate RESOLUTION rather than enough DPI. I had to slap my forehead several times after reading this – it brought it all home and made me realise I really had been making a mountain of a molehill.
(Ironically, if you can make a mountain of a molehill and still have amazing resolution – it is printable at a very large print!)
- This article at worldstart.com also tells how resolution becomes your DPI . Again, it hits the nail on the head and makes it all quite easy to comprehend.
- This forum post at photography-on-the.net (for Canon dSLR users predominately) sums it up quite nicely.
“The reason people recommend 300ppi is because that is roughly the limit of what human eyes are capable of distinguishing. There is little or no point ever printing at higher resolutions because you just won’t be able to see the difference. But of course you will appreciate that the further away from something you are, the less you can see the detail. So you don’t need 300 ppi if you’re making large prints or posters that will be on the wall. You only need 300 ppi if you’re looking at something close-up .“
- For those still unsure about it all, and there’s no embarrassment if you are – here are two different sites that should help. This one has an online converter of pixels to inches (for monitors, printers and scanners). This one allows you to input the DPI to get the measurements of your image.
- Those wanting to take the next step, and are deadly serious about getting their DPI correct – and don’t want to spend a lot of money: Mihov has a freeware program that should do the trick.
I know I have harped on this for a while, but it’s finally all fallen into place: DPI is not about quality of image, it helps determine how wide and high you can print an image.
Finally, I get it. Now I can write about photography and camera stuff…
David Burren
All true, as long as you’re talking about ppi (pixels per inch) rather than dpi (dots per inch).
Inkjet printers lay down multiple dots of multiple inks per pixel of image, which is why you see printers advertising resolutions like 2880 dpi (on a printer which can probably handle a maximum of 360 ppi).
Images have PPI, multi-dot printers use DPI underneath that.
But enough people have got confused by it over the years that there’s even software (e.g. Epson’s scanning software) which still talks about DPI when it means PPI, so don’t feel too bad. ;-)
Cheers
Stephen Mitchell
Thanks David – But that’s more than most photographers need to worry about.
I read something in one of the links above about how some printers claim to print with high level PPI (and DPI in some cases), yet once you reach 280 DPI on a A4 sheet of paper, nobody’s going to be able to actually SEE if the quality is better!
Which makes you wonder how many other printers out there are over hyped (and over-priced) and are really only giving the minimum specs to suit the average 20/20 vision?
Enough about this.
VIVA LA RESOLUTION. (I doubt that’s original, but it felt good to say it!)
webgrrl
i came across this article not too long ago that worthwhile reading too : I RESOLVE TO BE MORE RESOLUTE : UNDERSTANDING RESOLUTION
Stephen Mitchell
Thanks webgrrl. I wrote this long post here in response—but somehow it got destroyed with some error-msg a few minutes ago. I hope it didn’t get destroyed into binary dust and is sitting on the server somewhere! (crosses fingers in vein hope)