30 x 40 cm == 12 x 16 inches
51 x 76 cm == 20 x 30 inches

Agreed, one can get a nice looking 11x14" print from 35mm.

When you get to 20x30 it needs 4x5" negatives.

A 4x5" enlarged to 20x30" has the same quality as a 35mm
negative enlarged to 5x7" (~13x18cm).

I have an old 36" Dagor I have always been meaning to make a 20x24
camera for.  A simple one: a 2x4 frame covered wrapped in black
garbage bags, scale focus - that sort of design philosophy.  With
a 20x24" negative you don't have to worry about getting a large
format enlarger, as you do with an 8x10.

"Sam Carleton" <scarleton-nospam@miltonstreet.com>

As I said: "Gustibus non est disputatum."

Above the fireplace in the living room!  The image demands it.
It would lose it's raison d'être if hung in the basement.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer:  Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Yes, it's called SO-253 Holographic.  It has an ASA of about 2 and will do
about 400 lp/mm or more in noon summer sunlight.

Typical exposure is 1/125 at f-2

Larry

Once the discontinuation of TP became evident, I ran my own tests on same
subjects to try to find a substitute (all 35mm):
- TP in Technidol using Kodak's "shaker" agitation
- PanF in XTol 1+1
- TMX in XTol 1+1
- Acros in XTol 1+1
The last three processed by rotation. Developers/dilutions were not chosen
to desperately obtain the finest grain possible but because they are what I
use commonly.
Partial prints were made at 16.5x magnification (complete prints would have
been 16x24").
There was a clear difference in favor of TP (both grain and resolution) but
I wouldn't say it was so enormous.
Anyway, like always with films, personal taste is the final judge.
Not to mention lens quality and shooting conditions are essential when going
low-speed/high-resolution films.

I didn't find a real and complete substitute for TP but found acceptable
replacements in terms of sharpness and grain.
If I bought several TP rolls (well, bulk rolls, 45m for TP ...) and put them
in the freezer, this is not only for resolution/grain characteristics but
also, and perhaps more, because its special spectral response that gives a
particular "glow" to the skin.

Actually, Sam seems to work in 35mm, so unless he buys another equipment (MF
or LF), he has to go with it.
He doesn't seem to look at the prints with a loupe either.
So, I see mainly two options for him:
- He can do what many have already done: buy TP before it's gone completely.
- But, I would suggest he tries also other low-speed films, he may find one
that fits his needs.

It's just a matter of magnification, I'm pretty sure you can see "lumpy cold
oatmeal" TP grain if you push it over its limits ...

I've thrown away my test prints but. if needed. I can reprint and scan them.

Regards,
Claudio Bonavolta
http://www.bonavolta.ch

With Sam I mean Nicholas of course, sorry

I've made an 8x10 print from a 4x5 negative that showed grain.  I used
Arista.EDU ISO 400 film.  Very grainy film...I probably won't buy it again.

I've wisened up and now use Tmax 100.  There is _no_ grain visible in any
print I've made.

You should try the 4x5 before making such a judgement.

I don't want a 13 x 18 cm, but a 20 x 30 INCH!!!!  35mm T-Max 100
would be fine for a 13x18 cm print, I want a poster of the image.
Oh, and here is the link to the image, again:

http://www.miltonstreet.com/scarleton/images/black.jpg

The idea is to get a poster size of the image.

Sam

POTA was originally published by a photo researcher
and chemist named Marilyn Levy as an extended range
developer to capture extremely wide luminance ranges
on the order of 20 stops (i.e, atomic bomb blasts.)
Various references say she worked for (1) US Army
Signal Corps Laboratories (2) US Navy Photo Optics
Technical Area. I surmise POTA is an acronym for
Photo Optics Technical Area since it was simply
sodium sulfite (30 g) and Phenidone (1.5 g) in a
liter of water.

Original publication was in Photographic Science and
Engineering, v. 11 p. 46 (1967) and later generally
referred to as "POTA".

Not completely true either.

If your enlarging a 35mm negative to 8x10 and an eight x ten negative
to 24 x30 and looking closely at detail then yes your are probably 100%
correct. However if thirty mm is enlarged to 8x10 and the 8x10 is
contact printed at 8x10, then Format Does play a critical sharpness and
detail rendering roll.

You must have a different definition of image detail from the one to which
I am accustomed.

A simple exercise in limits shows this.

Imagine an extremely small format camera, whose film has 10 grains in
height and 15 grains in width. So 150 entities capable of rendering
whatever image the optical system can project on the film. Clearly, the
greatest possible limit on image detail would be about 150 elements.

But with a film like TriX in a format of 24x32mm, with well over a million
grains per square inch, the greatest possible limit on image detail would
be over 1.5 million elements.

Now with a 20 square inch negative instead of a 1.5 square inch negative,
that bound goes up. It goes up as the negative area until you reach the
limit of lens resolution or the film resolution, whichever happens first.

    I have to disagree. A 105mm lens on 35mm may well resolve
100lpmm and be used to photograph a portrait using TMX (140lpmm
resolution) of a subject at 10 ft. (I like round numbers) but it's not
going to be equal in detail to a photograph made on a 5X7 camera using
a 500mm lens. The degree of enlargement is most likely not going to be
the same AND the larger negative will have more image information
contained in the silver matrix. The 35mm negative has 864mm.sq. and
the 5X7" negative has 22580.6mm.sq.

    When it comes down to it, there is no replacement for good ol'
displacement. Walk tall and carry a bigger camera.

Regards,

  John S. Douglas, Photographer -  http://www.puresilver.org
             Please remove the "_" when replying via email

Of course it does. The bigger the film format the bigger
the detail; focal length is related to format.

The "City & Guilds" rag from the UK?  I am not sure this is
a very trustworthy source.  It's a nice and chatty magazine, but
it could have been better titled "Some snaps we took after we got
drunk in the pub".

The author is testing gigabit film taking pictures on ASA 40 film,
hand-held, using a 28-70 zoom and on a cloudy day.  I am sure it
looks better than the only other films he uses: they are ASA 400
or nothing, he admits.

From this auspicious start, we have, quoting for review purposes:

 "The leaflet that accompanies the film is complex ... it needs
  a few reads to get the point. A number of references are made
  to the aperture of the lens relating to resolution. This
  could be applied to any film, but I think is best ignored for practical
  photography, so don’t let this section put you off"

The aperture of the lens for maximum resolution is best ignored when doing
extreme resolution photography?  This cat's from the moon.

 "Don’t bother with a handheld meter – far more exposure errors are made
  by people who haven’t got a clue how to use one than by the TTL system
  of a camera."

The subtext: If you are dumb enough to still be reading this article you
probably aren't smart enough to take your camera off 'Auto', so don't.  I
see his point about aperture and resolution now.

 "No problems with loading or rewinding were experienced."

That's a relief to know.

 "Another point is made that TTL metering may not be
  accurate with this film, due, they say, to the film reflecting more
  light into the measuring cell than conventional emulsions. Ignore
  this only partly."

At your peril if you are using TTL metering, but we've already decided
most people are too dumb to use a handheld meter or set the ISO manually
to compensate.  Viz. the author left his camera on DX.  And the manufacturer
only 'says it': not like it's true, is it?

  "I developed the film as instructed ... the negatives were way too thin."

Could it have been the exposure?  Something about the film reflecting
more light?

  "Most of the shots on the first roll were useless. I whipped
   myself with split birch twigs as a suitable punishment."

The author would have you believe he went to Eton.  He didn't.

  "I blew up a Gigabit negative to 20x30in and the result was still
   exceedingly sharp. I was gobsmacked."

There it is folks, the result of all this testing is "the film hit
him in the face."

This may be great film, and it has been on my list to test (though if
I liked it what would I do with ~1,000 feet of TechPan in the deep
freeze), but this article does not make me want to go out and shoot
some of the stuff:  I just don't like getting hit in the face.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer:  Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

For those who liked the discontinued Tech PAN?  .....the Gigabit could be an
option.
I like the film. Only 20 sec. fixing time in normal film strength
fixer.....one has to remember.

Usually lattitude and contrasty are mutually exclusive.