Re: [9fans] PNG and APE (cntd)

["Bruce Ellis" <bruce.ellis@gmail.com>]

Yes, 12 bit was added to postscript for x-rays.

brucee

On 4/28/06, Jack Johnson <knapjack@gmail.com> wrote:
> On 4/27/06, Charles Forsyth <forsyth@terzarima.net> wrote:
> > > And, BTW, PNG allows 16-bit per colour, a 48-bit depth per pixel.
> > > Thanks to libpng, my "npng" can render these as 24-bit images.
> >
> > ``the human ear can't hear as high as that / still, it ought to please any passing bat''
>
> I used to do some image fiddling a long time ago (image prep -> TGA
> for television), and came across some info regarding medical x-ray
> photographs being stored in a 12-bit grayscale format.  It's likely
> that so fine a variation is either above or right on the edge of human
> perception (given current working environments), but one
> counterargument is that maybe it's not a human looking at the data.
>
> Plus, I think 12 bits per color would be right around the limit of
> film, something like a 4000:1 contrast ratio, so depending on the
> scanner you'd likely be pushing the limits of the original medium
> anyway, "lossless" transfer from analog to digital, whether or not
> you're in a good position to make use of the data.
>
> Archaeologists have the same problem all the time, looking at data
> gathered by previous scientists and realizing the original gatherers
> didn't save enough information for the current questions, so now they
> tend to swing the opposite direction and record all the minutiae so
> that years later someone can glean new information from an old dig.
>
> One day, you may be a bat.
>
> -Jack
>