[filmscanners] RE: 3 year wait

["Laurie Solomon" <laurie@advancenet.net>]

In listening to this discussion, I cannot help but think that we are not all
talking about the same thing and distinguishing between what I will call
"actual ppi" and "effective ppi."

In hopes of helping to resolve what may be a phantom debate, I think it
might be useful to note that that "actual optimum resolution" for a 4K
recorder is 4K lpi or to use doogle's figures under 3000 ppi per lineal inch
measured on the long or horizontal side of the film frame; so its "actual
ppi" is less 3000 pixels per each inch no matter what film format or size
when operating at maximum resolutions.  However, when that resolution is
used on film frames larger than 35mm, the "effective ppi" is reduced
depending on the lineal dimension of the horizontal although the "actual
ppi" remains at less then 3000ppi.  While this may be stating the obvious -
in which case I am sorry, I hope that it may help suggest that you are both
saying the same basic thing except you may be confusing the "actual" with
the "effective" resolutions when moving from 35mm to a larger film.

>From what I know, the 2K, 4K, 8K, and 16K designations all express the
nominal maximum resolutions of the recorder in question; and any recorder
can be set via software to record at lower resolutions than its nominal
maximum but not at higher resolutions than its nominal maximun.  However,
this does not mean that in all cases, the resolution setting established in
the software ( even if it is set at the nominal maximum) will actually
produce those resolutions.  Often with all but the most expensive pro
recorders, according to my research of what literature exists, most film
recorders will operate at lower than the stated maximum resolution even when
set for it.  Oviously, there will be exceptions to the rule; but that is
what Iunderstand to be the accepted wisdom in general.

I hope tyhis helps clear up some of the apparent confusion and cross-talk.

-----Original Message-----
From: filmscanners_owner@halftone.co.uk
[mailto:filmscanners_owner@halftone.co.uk]On Behalf Of doogle@doogle.com
Sent: Monday, May 13, 2002 10:14 AM
To: laurie@advancenet.net
Subject: [filmscanners] Re: 3 year wait


Date sent:              Sun, 12 May 2002 20:52:28 -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

> Hi Rob,
>
> > > > Am I then incorrect in my thinking that the 4K figure for the
> > > > filmrecorder is in ppi?

No, it's not ppi.

> > > It appears to me that the 4k figure for the filmrecorder is
> > simply the size
> > > of the sensor,
> >
> > Its not a sensor its a CRT...
>
> Yes, you're right.  I didn't think about that when I wrote it, I'm so used
> to talking about input devices (as this is a filmscanner list ;-), not
> output devices, and I do know it's not a sensor.
>
> > The image is rasterized into its components - this rasterization
> > can be 4K (or smaller)
> > (4032x2689)  to  8K ( 8192x5461)  ppi  that's Polaroids figures.
>
> But do they say ppi related to the recording output, and if so, is that
the
> maximum, and when projecting onto larger film formats, obviously that
"ppi"
> decreases?

See below.
4 K optimum file size run at 4K settings
and
8K optimum file size run at 8K settings
both have effective ppi ON the output film area of just under 3000ppi.


Again, from what you show for figures, it looks to be that 4k or
> 8k refers only to the physical number pixels of the imaging device on the
> long side.  I don't believe it is meant to be ppi, since for the long side
> of a 35mm projection, it would be 4k/8k projected across ~1.4"...and
> therefore be ~2850ppi (for a 4k recorder obviously).  Now, the imaging
> device may in fact be 1" along the 4k/8k side, and how relevant is that
> really, compared to the output ppi (which is what we've been talking about
I
> believe)?
>
> Regards,
>
> Austin

The effective ppi would be relevant to the output medium, ie the film size.
My Lasergraphics Mark III DPM at 4K:
4096 x 3362 (addressable) or 4096 x 2731 in 35mm proportions: slightly under
3000ppi
onto 35mm film
Bout the same ppi if going up to 8K pixel settings and running at 8K:
8192x6724 (addressable)

Mac



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