# Resolution Limit of the Human Eye?

Discussion in 'Digital Photography' started by Dr. Slick, Oct 12, 2003.

1. ### Dr. SlickGuest

Ok,

It's been discussed here numerous times, but this newbie has to
bring it up again.

I got a very high resolution scan of mine printed the other day,
and the limit on the digital printer (on photographic paper, not
ink-jet) was 400 ppi.

Someone wrote that 360 ppi was the limit the average human eye can
discern (i assume they meant that you can get as close as you wish,
and you will still not see the pixels). As this seems to make sense,
then a limit of 400 ppi would make sense too, as this is slightly
over.

When i got the prints back, the brightness and contrast were a bit
different than my screen at home...however, they were fantastic in
that i couldn't see any pixels at all.

Some of the ink-jet printers have a 300 ppi limit, and i wonder if
ink-jet turns out a bit worse than doing it on photographic paper.

What do you folks think?

Slick

Dr. Slick, Oct 12, 2003

2. ### Tom NelsonGuest

Tom Nelson, Oct 12, 2003

3. ### Don StaufferGuest

The eye resolution is rated in angle, since there is no standard of
distance. Using an angle rating allows you to compute linear resolution
at whatever angle you need. A good ballpark estimate is about one
minute of arc.

So we would have about sixty lines per degree.

Don Stauffer, Oct 13, 2003
4. ### Marvin MargoshesGuest

And there is a limit to how much detail can be shown on either photographic
paper or the paper used for photographs on an inkjet printer.

Marvin Margoshes, Oct 13, 2003
5. ### Happy HippoGuest

Don't forget the two processes are different. The printer uses
halftones/dithering whereas the prints won't have to...

HH

Happy Hippo, Oct 15, 2003
6. ### Paul H.Guest

The portion of the retina containing the most sensitive cones is a roughly
circular area called the fovea centralis which has a diameter of about 0.3mm
and a cone density of 199,000 cones per square millimeter.

Oh yeah--the full moon's image on the retina is about 0.2mm in diameter.

You do the math.

Paul H., Oct 15, 2003