Date sent: Fri, 10 May 2002 12:51:29 -0400
Send reply to: filmscanners@halftone.co.uk
From: "Austin Franklin" <darkroom@ix.netcom.com>
To: doogle@doogle.com
Subject: [filmscanners] RE: 3 year wait
>
> > When I say "4K", it means an image of 4096 x 2731, nothing more.
> > My film recorder can do 4K or 8K resolution.
>
> I guess that's the root of the issue I have. It's the same as calling a
> monitor X by Y resolution. Resolution is really not a good word in this
> case. Resolution, in the digital imaging field, means so many somethings
> (Ds, Ps, Ss or whatever) per inch. Inch is a standard unit of measurement.
> Apparently in "film recorder speak", the unit of measure is the long side of
> a 35mm piece of film (like in monitor speak, it's the physical size of the
> monitor)! Not, in my opinion, a very good metric.
Well, it's certainly not the same as a monitor, as the physical size of 35mm
film
doesn't vary :-)
4096 x 2731 can also be simply expressed as
36x24mm @ 2889.956ppi
> How does this work between different film formats? You kind of discussed
> this, but didn't give the "terminology". What if I am recording a 6x6 with
> an "8k" film recorder, that gives me 8k over a 6cm spread, right? But the
> same recorder used with 35mm film, gives me 8k over a 3.6cm spread? Same
> film recorder terminology ("8k"), but the ACTUAL resolution is entirely
> different (3555 vs 5333).
Well, first of all, and to reiterate a point or two, if you were going to 35mm
film on my
recordeer, you wouldn't need higher than 2731 pixels square. Since the image
can't go
any larger than the short dimension of the film frame, eh?. If you wanted to
scan at 8K
rez, then you'd have 5461 square maximum necessary, again, the short side of the
120 film. However, your 8K file, run on my recorder at either 4K or 8K
capability *on
35mm film* will not look any different on output (at least to your eye -
perhaps there
are "measurable" diffs, I dunno). That's why I say that the apparant resolving
power of
35mm film is reached at the 4096 x 2731 pixel count (using exact 35mm
proportions).
Your larger file *would* of course look good onto 120 film, imaged at 8K, and
would
look poorer if I should image it at 4K on 120 film. The smaller file, if put
onto 120 film,
would look the same whether imaged at 4K or 8K on recorder; that is, poor,
because it
didn't have enough pixels to maximize the film recorder's 8K rez, nor the 120
film itself.
As far as "physical size" of image, it's immaterial, only pixels matter, much
like
screen display. The total pixels simply size into the available space.
The finer technical point of putting either 11.1MP into that space or 44.7MP
into the
same space (ie 24x36mm) and how the recorder utilizes them, I'm unclear about.
Suffice it to say that either at 4 or 8K, there seems to be no diff. Again,
though, the
44MP image would of course look good on 120 film while the 11MP image would
suffer
greatly.
A square image gets placed in the center of the 35mm film chip. A long skinny
image,
gets placed in center also, with the long side of the film as the boundry. The
only
"enhancements" I routinely do is set color (usually black) for the film area
that does
NOT contain imformation within the 3:2 ratio; also, I generally size the entire
image
down to about 94% of the film frame to allow for no cropping from either slide
mount or
negative carrier. I can control other aspects also, if I chose to, including
brightness,
contrast, and color balance, but that's a fool's errand. It's important for me
to maintain
consistent default outputs and let client's match me. I use best controlled E-6
lab in
town also. Idea is that you can give me a TIFF/PSD (and others) file now and
again a
year from now and they will look identical if you haven't changed anything.
> BTW, thanks for the write-up on film recorders. Not an item I've ever been
> involved with, but certainly interesting to know something about.
>
> Regards,
>
> Austin
No prob, and as you can see, I don't know all the zact tech ins and outs of
even my
own, and have prolly talked as much around the subject as directly to it :-)
Much is based on observable results. And there's diffs within same "specs" from
different manufacturers, just as with digicams, whatever. This is an area in
which you
very much still get what you pay for. I used to run a "4K" film recorder at
university job
of many years and this one runs circles around it in terms of sharpness, density
range, lack of blooming, etc etc.
I guess I'd better get on with my day, beyond UseNet and Listservs, at least
for awhile
now :-)
Mac
Mac McDougald -- DOOGLE DIGITAL
500 Prestwick Ridge Way # 39 - Knoxville, TN 37919
doogle@doogle.com 865-540-1308
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