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A positive form negative



 
 
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  #1  
Old August 31st 08, 12:39 AM posted to rec.photo.darkroom
Peter Irwin
external usenet poster
 
Posts: 352
Default A positive form negative

piterengel wrote:
Hi everybody. I need for a certain work to obtain some positives from
negatives. I can't treat all film with positive method, because a part
of photos must remain negatives. I have a Contax Auto PC Bellow with
slide duplicator, and a RTS II camera. Photos are taken using an
Ilford Delta 100 film, developed in ID11. I want to use the same film
for positives. My questions a


The film to use for making positives on 35mm film is
Eastman 5302 Fine Grain Release Positive. I bought
some from Kodak in Toronto a few years ago for something
like $CAN 17 for a 100 foot roll. Kodak Motion Imaging
will probably still be willing to sell you a roll, it
is also listed for sale at electron microscope suppliers
because it is used by some models of electron microscopes
as well as by the motion picture industry.

The speed of 5302 is somewhere around 3 ASA, but this
depends a bit on development and how much blue and violet
are in the light source. Develop in Dektol 1:1 for 5 minutes.
You can adjust contrast a little by playing around with
different developers. The film looks like white plastic.
It can be handled fairly freely under any safelight for
B&W enlarging paper. You should have no trouble bulk loading
it into 135 cartridges by hand.

Peter.
--


  #2  
Old August 31st 08, 03:26 AM posted to rec.photo.darkroom
Richard Knoppow
external usenet poster
 
Posts: 751
Default A positive form negative


"Peter Irwin" wrote in message
...
piterengel wrote:
Hi everybody. I need for a certain work to obtain some
positives from
negatives. I can't treat all film with positive method,
because a part
of photos must remain negatives. I have a Contax Auto PC
Bellow with
slide duplicator, and a RTS II camera. Photos are taken
using an
Ilford Delta 100 film, developed in ID11. I want to use
the same film
for positives. My questions a


The film to use for making positives on 35mm film is
Eastman 5302 Fine Grain Release Positive. I bought
some from Kodak in Toronto a few years ago for something
like $CAN 17 for a 100 foot roll. Kodak Motion Imaging
will probably still be willing to sell you a roll, it
is also listed for sale at electron microscope suppliers
because it is used by some models of electron microscopes
as well as by the motion picture industry.

The speed of 5302 is somewhere around 3 ASA, but this
depends a bit on development and how much blue and violet
are in the light source. Develop in Dektol 1:1 for 5
minutes.
You can adjust contrast a little by playing around with
different developers. The film looks like white plastic.
It can be handled fairly freely under any safelight for
B&W enlarging paper. You should have no trouble bulk
loading
it into 135 cartridges by hand.

Peter.
--


The problem is that this film may now be available only
in 1000 foot spools but do check. Kodak may still have a
data sheet for it. The sheet gives development instructions
for various degrees of contrast, all using readily available
developers. While not many B&W movies are made now the film
was also used for special effects masks and other purposes.
The speed is comparable to fast enlarging paper and its
handled about the same way. Because the spectral sensitivity
is confined to the blue it can be handled under an OC
safelight although I think Kodak recommends a red light.
Processing is very much like RC printing paper. If you can
obtain it economically its definitely the stuff to use.


--
--
Richard Knoppow
Los Angeles, CA, USA




  #3  
Old August 31st 08, 08:52 PM posted to rec.photo.darkroom
Peter Irwin
external usenet poster
 
Posts: 352
Default A positive form negative

Richard Knoppow wrote:

The problem is that this film may now be available only
in 1000 foot spools but do check.


I hadn't known that. The Jan 31 2008 Price Change Bulletin
would seem to show 1000 feet rolls as a minimum quantity.
That may not be a complete disaster though. 5302 is one
of the cheapest films made, so I think that 1000 foot roll
might be around $120.

It also may still be possible to buy an 100 foot roll from
a microscope specialty store for around $20. I bought 100 feet
of 5360 from Ted Pella, since Kodak had a minimum order of 1000 feet
of 5360.

The PDF for 5302 is at:
http://www.motion.kodak.com/motion/uploadedFiles/US_plugins_acrobat_en_motion_products_lab_h15302.p df

Peter.
--

  #4  
Old October 23rd 08, 06:54 PM posted to rec.photo.darkroom
Richard Knoppow
external usenet poster
 
Posts: 751
Default A positive form negative


"piterengel" wrote in message
...
On 31 Ago, 04:26, "Richard Knoppow"
wrote:
"Peter Irwin" wrote in message

...

piterengel wrote:
Hi everybody. I need for a certain work to obtain some
positives from
negatives. I can't treat all film with positive method,
because a part
of photos must remain negatives. I have aContaxAuto PC
Bellow with
slide duplicator, and a RTS II camera. Photos are taken
using an
Ilford Delta 100 film, developed in ID11. I want to use
the same film
for positives. My questions a


The film to use for making positives on 35mm film is
Eastman 5302 Fine Grain Release Positive. I bought
some from Kodak in Toronto a few years ago for something
like $CAN 17 for a 100 foot roll. Kodak Motion Imaging
will probably still be willing to sell you a roll, it
is also listed for sale at electron microscope suppliers
because it is used by some models of electron
microscopes
as well as by the motion picture industry.


The speed of 5302 is somewhere around 3 ASA, but this
depends a bit on development and how much blue and
violet
are in the light source. Develop in Dektol 1:1 for 5
minutes.
You can adjust contrast a little by playing around with
different developers. The film looks like white plastic.
It can be handled fairly freely under any safelight for
B&W enlarging paper. You should have no trouble bulk
loading
it into 135 cartridges by hand.


Peter.
--


The problem is that this film may now be available only
in 1000 foot spools but do check. Kodak may still have a
data sheet for it. The sheet gives development
instructions
for various degrees of contrast, all using readily
available
developers. While not many B&W movies are made now the
film
was also used for special effects masks and other
purposes.
The speed is comparable to fast enlarging paper and its
handled about the same way. Because the spectral
sensitivity
is confined to the blue it can be handled under an OC
safelight although I think Kodak recommends a red light.
Processing is very much like RC printing paper. If you can
obtain it economically its definitely the stuff to use.

--
--
Richard Knoppow
Los Angeles, CA, USA


After a bit of time I'm back with few news.
I've tried to obtain positive from negative as follow.

NEGATIVE

I've used Ilford Delta 100 film developer in Perceptol full
strength
fo 15 mins. Subjects were macro images of iron dust modelled
with a
magnet. Camera: Contax RTS II, lens Zeiss Planar 60 f/2.8
Macro.
Negatives are good, reach of details, a little bit dark but
this is
not a problem.

POSITIVE

Equipment: Contax auto bellows with slice copier tool, RTS
II mounted
and Planar 50 f/1.7 as lens. I've extended bellows for 50 mm
to obtain
1:1 macro ratio. The lens was set on f/16, the minimum
aperture
available. I've used a TTL flash as light source (I've tried
with a
high power incandescend light source but results were
worst).

Film: Efke 25 developed in Rodinal 1+100, prebath of 1 min
in water,
than developer for 18 mins. This was a test film, for the
final work I
want to use Kodak Tech Pan filam (yes, I've few of them in
my
refrigerator...).

Problems: I've noted, as said, taht it is better to work
with flash
light; but the most important problem is that the center of
the
pictire is in focus and edges are not. This is a very big
problem for
me. I've not the bellows instructions manual but I don't
think I'm
doing something wrong. Before using my precious Kodak TP
film I hope
somebody can help me.

Thanks all

P.

This may be due to using the lens so far from its
optimum distance. All lenses with fixed position elements
can be optimized for only one distance and at others begin
to pick up aberrations. One of these is curvature of field.
In general, the faster the lens the worse the problem. If
you can adapt an enlarger lens to the camera it will
probably give you better results. but you really need a lens
optimized for a distance suitable for unity magnification.
You might get better results by contact printing. Leitz
made a small contact printing device for making 35mm slides
from negatives. Its called an eldia and I found one at a
local sale for not much.


--
--
Richard Knoppow
Los Angeles, CA, USA



  #5  
Old October 23rd 08, 09:20 PM posted to rec.photo.darkroom
Nicholas O. Lindan
external usenet poster
 
Posts: 1,227
Default A positive form negative

"piterengel" wrote

Contax auto bellows with slice copier tool, RTS II mounted and Planar 50
f/1.7 as lens ... problem is that the center of the pictire is in focus
and edges are not.


As Richard mentioned, try using an enlarging lens.
To mount an enlarging lens on a bellows just cut
a hole in a body cap and thread the lens into the
cap and mount the cap on the bellows.

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.darkroomautomation.com/da-main.htm
n o lindan at ix dot netcom dot com


  #6  
Old October 24th 08, 12:27 AM posted to rec.photo.darkroom
Thor Lancelot Simon
external usenet poster
 
Posts: 163
Default A positive form negative

In article ,
piterengel wrote:

Mr. Knoppow, as any other time you're right. The problem was lens.
I've adapted Planar 60 Macro to slide copier, working at f/22. Results
are very good. In the meanwhile I've ordered on eBay from England an
adapter ring from M42 to Contax to be able to mount enlarger lens on
bellows. Till now it is not arrived but surely I'll try with this too.


This may work. But it is unduly complex.

I would second Richard's suggestion of contact-printing the film. With a
sufficiently dim light, even standard 25ASA film will work to make the
positives. Simply cut lengths of the unexposed film to match the lengths
of the cut strips of developed negative film, align them carefully, and
place them in a standard glass-front, foam or rubber-backed contact
printer, or, if you do not have a contact printing frame, use a heavy
sheet of glass (1/4" or thicker) on top of the two pieces of film, on
top of a clean, black surface.

It will take a few tries to calibrate exposure but you can use normal
development times and will achieve excelent results. And there will be
no focus or sharpness problems -- guaranteed.

Slide copiers exist really only to deal with the annoyance of copying
already cut and mounted slides, which are too thick to be contact
printed as I describe above with good results.

--
Thor Lancelot Simon
"Even experienced UNIX users occasionally enter rm *.* at the UNIX
prompt only to realize too late that they have removed the wrong
segment of the directory structure." - Microsoft WSS whitepaper
  #7  
Old October 24th 08, 06:08 PM posted to rec.photo.darkroom
Richard Knoppow
external usenet poster
 
Posts: 751
Default A positive form negative


"piterengel" wrote in message
...
On 24 Ott, 01:27, (Thor Lancelot Simon)
wrote:
In article
,

piterengel wrote:


Very long previous thread snipped...............

Today it is arrived the adapter ring I've described above.
So I'll try
with 50 mm enlarger lens first, then with contact print
too. In this
last acse, do you have an approximate idea on time of
exposure? I
think to place the column at least 10 in high with
completely close
diafragm of lens (f/22). so how long could be the
exposition? or can I
try to use an external exposimeter to determine this?


Use an enlarger as your light source. You may have to
put something in to cut down the light. Even a sheet of thin
paper in the negative holder will work. Most exposure meters
will not read low enough to be useful for this but you can
get some idea of needed exposure by knowing that most
variable contrast enlarging papers are around ISO-6 when
used without a filter and around ISO-3 with a medium
contrast filter. Find the exposure for a good print and
divide that by the ratio of paper speed to film speed.
Otherwise you will have to find the exposure by making a
test strip, that is making several exposures about one stop
apart (each double or half the last). You really only have
to do this once to calibrate the setup.
Also, I think it may be possible to use a SLR camera
with a through the lens exposure meter to make the
measurement by laying it under the enlarger and exposing for
about 5 times the white light reading made with a clear
negative (no image) in the enlarger. The reason for the
clear negative is to account for the density of the support
which is considerable for most 35mm negative films due to
the anti-light-piping pigment in them.
I suggested the Leitz Eldia contact printer before
because I think they are not too difficult to find and are
very convenient for this. They were originally meant to
print onto non-color-sensitized slow film of the sort meant
for making B&W motion picture prints. One of these films,
Kodak Fine Grain Release Positive, is ideal but is now
available only in 1000 foot spools. This film has about the
same speed as fast enlarging paper is processed in print
chemicals. Agfa and Ilford made similar films but I suspect
they are long off the market.
Slow, fine grain, pictorial film works fine but most
35mm negative films have a pigment in the support which can
not be removed and makes the slides just a little darker
than the clear support on the printing film. Not a real
problem but you should be aware of it.
For projection the positive needs to be rather contrasty
compared to normal negative contrast. Most of the very slow
fine grain films are inherently contrasty and its possible
to get the necessary contrast and high shadow density with
films like T-Max 100 by processing them is somewhat high
contrast developers like Dektol. I think Kodak has some
limited information on this use but don't know specifically
where it is.
All this makes the procedure look more complicated than
it is. Positive slides for projection were the rule for many
years before 35mm reversal films came on the market, hence
the Eldia and similar devices.


--
--
Richard Knoppow
Los Angeles, CA, USA



  #8  
Old October 24th 08, 06:53 PM posted to rec.photo.darkroom
Thor Lancelot Simon
external usenet poster
 
Posts: 163
Default A positive form negative

In article ,
Richard Knoppow wrote:

contrast filter. Find the exposure for a good print and
divide that by the ratio of paper speed to film speed.


That would be, of course, "the exposure for a good print
of the same size as the lighted area cast by the enlarger
set to cover the contact frame" -- the exposure with the
enlarger column at the same height, basically. I'm sure
Richard knows this but I got it wrong the first time I
tried this process so I thought I should elucidate.

Otherwise you will have to find the exposure by making a
test strip, that is making several exposures about one stop
apart (each double or half the last). You really only have
to do this once to calibrate the setup.


This is what I have always found simplest.

Slow, fine grain, pictorial film works fine but most
35mm negative films have a pigment in the support which can
not be removed and makes the slides just a little darker
than the clear support on the printing film. Not a real
problem but you should be aware of it.
For projection the positive needs to be rather contrasty
compared to normal negative contrast. Most of the very slow
fine grain films are inherently contrasty and its possible
to get the necessary contrast and high shadow density with
films like T-Max 100 by processing them is somewhat high
contrast developers like Dektol.


Another option which occurs to me is to use Kodalith. Is it
still sold in 35mm roll film? For the longest time, it was,
but under a different (and strange) product name. It does not
have a pigmented base, and if developed in a very dilute
developer (HC110 dilution F works; POTA would probably work
better) will in fact give negatives of slightly higher than
standard contrast. It's also *very* slow, and can be handled
under a dim red safelight. Perhaps it is almost ideal for this
use. The disadvantage is that more work will be needed to
calibrate exposure and development since Kodak's tables won't
be helpful.

What I did last time I needed nice snappy slides from copied
small format negatives was develop normally and then intensify
with very strong selenium toner (1:3). This gives a color
change, which is not ideal, and is wasteful of the somewhat
expensive toner, but I was in a hurry and it got the job done
with the materials I had on hand, and I didn't have to recalibrate
my development system for some oddball developer like Dektol 1:10.

Chromium intensifier, if you can still get it, would probably work
better.

--
Thor Lancelot Simon
"Even experienced UNIX users occasionally enter rm *.* at the UNIX
prompt only to realize too late that they have removed the wrong
segment of the directory structure." - Microsoft WSS whitepaper
  #9  
Old October 28th 08, 01:11 AM posted to rec.photo.darkroom
Richard Knoppow
external usenet poster
 
Posts: 751
Default A positive form negative


"Thor Lancelot Simon" wrote in message
...
In article
,
Richard Knoppow wrote:

contrast filter. Find the exposure for a good print and
divide that by the ratio of paper speed to film speed.


That would be, of course, "the exposure for a good print
of the same size as the lighted area cast by the enlarger
set to cover the contact frame" -- the exposure with the
enlarger column at the same height, basically. I'm sure
Richard knows this but I got it wrong the first time I
tried this process so I thought I should elucidate.

Otherwise you will have to find the exposure by making a
test strip, that is making several exposures about one
stop
apart (each double or half the last). You really only have
to do this once to calibrate the setup.


This is what I have always found simplest.

Slow, fine grain, pictorial film works fine but most
35mm negative films have a pigment in the support which
can
not be removed and makes the slides just a little darker
than the clear support on the printing film. Not a real
problem but you should be aware of it.
For projection the positive needs to be rather
contrasty
compared to normal negative contrast. Most of the very
slow
fine grain films are inherently contrasty and its possible
to get the necessary contrast and high shadow density with
films like T-Max 100 by processing them is somewhat high
contrast developers like Dektol.


Another option which occurs to me is to use Kodalith. Is
it
still sold in 35mm roll film? For the longest time, it
was,
but under a different (and strange) product name. It does
not
have a pigmented base, and if developed in a very dilute
developer (HC110 dilution F works; POTA would probably
work
better) will in fact give negatives of slightly higher
than
standard contrast. It's also *very* slow, and can be
handled
under a dim red safelight. Perhaps it is almost ideal for
this
use. The disadvantage is that more work will be needed to
calibrate exposure and development since Kodak's tables
won't
be helpful.

What I did last time I needed nice snappy slides from
copied
small format negatives was develop normally and then
intensify
with very strong selenium toner (1:3). This gives a color
change, which is not ideal, and is wasteful of the
somewhat
expensive toner, but I was in a hurry and it got the job
done
with the materials I had on hand, and I didn't have to
recalibrate
my development system for some oddball developer like
Dektol 1:10.

Chromium intensifier, if you can still get it, would
probably work
better.

The exposure ratio I used is one Kodak recommended for
calculating exposure when copying. Whte paper is placed on
the easel and measured. The exposure is then multiplied by a
factor of 5. Actually, this is the same as making the
measurement with an 18% gray card. In the case of an
enlarger the light measured is that light falling on the
film so some correction is necessary.
I like the idea of using lith film. By choice of
developer the contrast might be made the same as positive
printing films. Kodak Fine-Grain Release Positive used to be
dirt cheap and came in 100 foot spools. No more but there
may be FGRP available outdated. Because it is so slow the
chances are it can be quite old without being fogged. Its
ideal for making B&W slides from B&W negatives but won't
work for color negatives because it is sensitive only to
blue light. In fact, it can be handled under a red
safelight. Some lith film is blue sensitive but panchromatic
lith film has been made (maybe still?) and might be quite
useful.


--
--
Richard Knoppow
Los Angeles, CA, USA



  #10  
Old October 28th 08, 01:53 AM posted to rec.photo.darkroom
Thor Lancelot Simon
external usenet poster
 
Posts: 163
Default A positive form negative

In article ,
Richard Knoppow wrote:

I like the idea of using lith film. By choice of
developer the contrast might be made the same as positive
printing films. Kodak Fine-Grain Release Positive used to be
dirt cheap and came in 100 foot spools. No more but there
may be FGRP available outdated. Because it is so slow the
chances are it can be quite old without being fogged. Its
ideal for making B&W slides from B&W negatives but won't
work for color negatives because it is sensitive only to
blue light. In fact, it can be handled under a red
safelight. Some lith film is blue sensitive but panchromatic
lith film has been made (maybe still?) and might be quite
useful.


The 35mm Kodalith I remember was "Kodak Ektagraphic HC". It's been
discontinued and I am not sure *any* Kodalith remains in production.

Wow.

--
Thor Lancelot Simon
"Even experienced UNIX users occasionally enter rm *.* at the UNIX
prompt only to realize too late that they have removed the wrong
segment of the directory structure." - Microsoft WSS whitepaper
 




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