Re: 16 bits = 15 bits in Photoshop?
Re: 16 bits = 15 bits in Photoshop?
- Subject: Re: 16 bits = 15 bits in Photoshop?
- From: email@hidden
- Date: Fri, 15 Apr 2005 12:39:16 EDT
Bruce Fraser writes,
>>What Dan's tedious and fundamentally specious arguments deliberately
miss is that the need for greater bit depth has absolutely nothing to
do with reproduction and everything to do with editability.>>
But you have made that point so clearly that nobody could possibly miss it,
deliberately or not. You have said,
"If you really start out with a RAW image in high-bit form and a raw image
downsampled to 8 bits, the difference really is night and day...But it's totally
obvious to anyone who looks that it's very advantageous to do the big moves
on high-bit data. "
There's now been probably a dozen people, including myself, who've made
serious efforts to test this proposition, and several of them have published the
results.
People GET that you are talking about an uncorrected image. Right. 16-bit
studio shots by high-quality digicams; 16-bit outdoor shots of high quality;
16-bit shots by consumer-level cameras. 16-bit scans of high-quality chromes;
16-bit scans of older prints of poor quality. In each case, make a copy of the
image, convert one to 8-bit, leave the other in 16-bit, and make the same series
of changes.
People GET that you are talking about big moves. *Really* big moves.
Unimaginably, incomprehensibly big moves, stacked up one on top of the other,
sometimes contradicting one another. Series of enormous moves. Moves so huge that
anyone who needs them has hundreds of problems worse than bit depth.
People GET that some pictures need to have the highlights emphasized and
others the shadows and others both, or neither. The people who have tested this
have tried every scenario they can think of.
People have done all this, and we're still looking for a "night and day"
difference. We're looking for this "totally obvious" stuff. Nobody who has done
this side-by-side testing has found anything more than that the two competing
files are not identical. Not even a mild preference for one as opposed to the
other.
>>We can capture much more than we can reproduce. That's why
photography is an art. Higher bit depths let us decide which parts of
the tonal range we've captured we wish to emphasize and which parts
we wish to compress.>>
You have posted this contention hundreds upon hundreds of times. If you have
that much time available to hype it, surely you have the small amount of time
it would take to construct an example image, using a real-world color
photograph, that would illustrate how the higher bit depths were helpful in whatever
it was you did to emphasize or compress that tonal range.
If you say that there's a "totally obvious", "night and day" difference in
your work, but you're don't have time to demonstrate it, and nobody else can
reproduce it, then people might start to conclude that it's not the extra bits at
all, but possibly the garlic you wear around your neck to ward off the
excessive-conversion vampire.
If you or your partner can actually produce a single image that can be shown
to benefit from being worked in 16-bit, it would be a considerable public
service. Obviously nobody can ever prove that no such image exists; it would seem
like somebody ought to be able to prove that at least *one* such image does.
Nobody has been able to prove that so far, and some people have tried quite
hard. Are you in a position to help out?
Dan Margulis
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden