Re: slide vs print

[P3D John Ohrt <johrt@xxxxxxx>]

P3D ron labbe wrote:

> > A contact print for a Holmes
> >card can have greater resolution than a 35 mm transparency or perhaps
> >even a 60 mm transparency simply because it is a larger format.
> 
> I submit that the resolution in a 35mm Kodachrome 25 transparency is better
> than any 3" contact print.

Which resolution?  Relatively speaking, Kodachrome 25 has an inherent
resolution of about 4000 pixels per inch assuming you have the camera
and viewer to support it. I don't know of any paper that has that
relative resolution.  But absolutely speaking, the print is more than
twice as large as the 35 mm slide, so it doesn't have to have the same
relative resoltuion.  Get the difference.

In reality, the optics of the viewers will never let you see any
difference anyway.  The quality of the camera and the viewer have more
importance than the resolution of the film when it comes to viewer type
presentations.  So in arguing "slides" vs "Holmes cards", resolution at
the level of Kodachrome 25 is massive overkill.

I'm sceptical that any "real" stereo camera has good enough optics to
use the inherent resolution of Kodachrome 25.  If they did, they would
cost many thousands of dollars. Even a capable 35 mm SLR will put you
into 4 figures, no problem.  A far more important point is its colour
rendition, superb.  Granted, you have to deal with a very slow film
demanding precise exposure settings, begetting exposure times
impractical for many subjects.  But if you want a comparable negative,
you get the same problems.  In fact that's true upto 400 speed film,
which is widely used both for "slides" and "prints".

 
> >You are overlooking the fact that positives are not necessarily
> >transparencies. (eg. Polaroid positives, or shooting directly to print
> >stock.)
> 
> I thought we were talking about the usual stereo formats, why bring up some
> virtually unused formats?

I am, unless you think Holmes cards are virtually unused.  :-)  

Polaroid Spectra format is a nominal 2 7/8 x 3 5/8 format.  It as
suitable as any 4x6 format to create a Holmes card.  Continuous tone
digital printers have convenient sized outputs.  There are lots of ways
to get positive prints that don't involve negatives.  There are ways to
get slides from negatives as well.

What I am getting at, is you among others have an idee fixe, that is
that positive media is transparent media, and that print media is
opaque.  It just ain't so.  You can make a positive transparency from a
negative just as you can make a paper print from a positive film.

Agreed that 35 mm slide pairs and Holmes cards are popular media, they
are popular because they are relative inexpensive not because of any
other inherently superior properties, which they just don't have anyway
(IMO).  I do consider "inexpensive" to be a very significant property. 
:-)

In fact, it can be argued that the "slide" approach is inherently
inferior because it doesn't permit adjustment of tone, skew, rotation,
or magnification variances easily corrected in a print process.  Even
"cropping" is not simple.  Granted both approaches are simple if the
images are well matched and composed.  

Another problem with "slides" is that there is no agreement on the media
size or mounting specifications for viewing, never mind a common viewer
specification.  Projection or slide pairs is a different matter, the
only problem there is the cost of mathched projectors.  

Perhaps we can avoid this with MF transparencies if we work together! 
The big reason MF slides look so much better than 35 mm slides is that
the format is larger.  A second-hand, functional Lubitel camera (a dirt
cheap Russian TLR MF camera made in the 80's) can produce better slides
than a top of the line 35 mm camera simply because of the format size.

For example, if I create an anaglyph from 8x10 negs and print it at
8x10, I can assure you that it's resolution is going to be better than
any "slide", even if I display it as a backlit transparency!

If anyone is worried about resolution, they should be looking at large
anaglyphs or at least medium format.

The reason I replied in the first place was an effort to get people to
open their eyes.  You appeared to have limited view of alternatives and
the artistic influence on the choice of media in your posting.  Perhaps
I was overly aggressive in my reply.

While I work at developing my "lab" to create Holmes cards,  I dream of
anaglyphs from negatives or positives taken by "real" cameras.  Large
Format!

Regards,

--
John Ohrt,  Regina, SK, Canada
johrt@xxxxxxx



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