How to find the ppi of a scanner.

My 4 in 1 HP printer has broken. I have a relatively good laser printer, but need something similar to use as a fax, scanner etc.
Unfortunately, only the dpi's are displayed and not the ppi.
Where would i find it?
The ones that I am interested in are Canon MX410; Lexmark Pro 205, HP J4 500 or HP 6500A.
Can anyone help?

 

For the purposes of decoding marketing half lies and techno babble, dpi and ppi are the same thing. You'll want just the Optical or Native DPI, and you'll usually see that number doubled. For example, your Canon MX410 is a 1200 dpi scanner, but Canon or retailers will likely say "2400 x 1200 dpi". The reason being that their stepper motors can move the scan head half a pixel, doubling the pixel count in one direction. You'll also see the term LPI or Lines Per Inch, which is different yet similar. Completely ignore any number that's "interpolated" as that's just a pixel splitting computer manipulation of the actual numbers.

For most graphics, 300-600 is sufficient. For most text 150 is sufficient. When you want to go beyond that is when you want to enlarge the ouput or enlarge a print from the scan.
Also keep in mind that these are just numbers, actual optical quality also comes into play, but that's difficult to quantify and even if they did the manufacturers would likely give themselves all A+++ ratings as it's a subjective quality.

MX410 = 1200
HP Officejet J4500 = 1200
Lexmark Pro 205 = 1200
HP Officejet 6500 E709a = 4800

 

Thanks, but just for comparison sake- 1200 dpi and 4800 dpi would be roughly how many ppi?
There are some old photos I want to scan and enlarge. I usually work on Photoshop at 300 ppi.

Thanks!

 

Maybe this article will help.

http://www.andrewdaceyphotography.com/articles/dpi/

 

Short answer: 1200 dpi = 1200 ppi, 4800 dpi = 4800 ppi. Both numbers are still the printed size that you scanned, as in a 4x6 is still a 4x6 whether you scan at 300, 1200, or 4800 dpi.

Long answer: The difference between dpi and ppi are dots vs. pixels, or printed material vs digitally displayed material. Once you scan the photo it is interchangeable (some may argue this till the cows come home but it's interchangeable). So if you scan something at 1200 dpi, then work on it at 300 ppi, you have enough information scanned to enlarge 4 times without having to resize in photoshop. If you're doing touch up work this helps a lot.

The one thing that hangs people up the most is the per inch part. If you don't specify a printed size, you aren't really changing anything. YOU have a base size though that you're dealing with, the printed photograph. If you scan a 4x6 in at 1200 dpi, then print that at 300 ppi, you technically can get a 4x enlargement out of the print. That's not to say that it would look nice though, it would just have enough pixels to enlarge it 4 times without using resize in photoshop. But since only enough resolution was printed to make the print at that size in the first place it's not like you can take a 4x6 and make it a 40x60 inch print and make it look as good as a print that had enough pixels to make a 40x60 in the first place.

Bottom line: 1200 dpi is usually more than enough for most applications. 4800 dpi would give enough resolution to see the fibers of the paper when viewed 1:1 in photoshop. A 4x6 @ 4800 dpi would also be an incredibly large file, even if just a jpeg. A tiff would require more RAM than a 32 bit computer could use. To put it all in perspective, to display a 4x6 full sized to fit on a full sized HDTV screen you only need 320 dpi, and at that you're still cutting off a portion of the top and bottom of the image (HDTV is a different aspect ratio).

If you're doing photographic work or graphic reproduction and manipulations then accurate color rendition would be far more important to me than actual dpi, given that all 4 models listed are of sufficient dpi for that work.