As their color homologues, B/W slides are particularly beautiful.
Several techniques are available to obtain them.
A slide should meet the following criterias:
- positive image
- high contrast (gamma around 1.5-2.0)
- film base as clear as possible
Although this is not their primary goal, it's possible to make prints from
Tetenal sells a kit for normal B/W paper.
It's also possible to use a procedure similar to the inversion of films (as
described lower) adapted to papers (low contrast developers).
Scala is a film developed to obtain directly slides with its specific process.
Kodak has a special developing kit "KODAK T-MAX 100 Direct Positive Film Developing
Outfit" (documentation J-87) usable with TMax 100, Technical Pan and, probably,
several other standard films.
The same kind of treatment are (or were, I'm not sure they are still produced)
available at Ilford under the name "Ilfodia" and Tetenal
under the name "SW-Dia-Kit".
These kind of kits use the same principle as described in the next chapter, the
inversion being usually obtained by a chemical step to simplify.
It's also possible to use any B/W film and invert it during the process to obtain a
Practically, only low sensivity films have a sufficiently clear base.
The principle consists to invert the film during the process:
- First development, the image is negative
- Bleach & clear, the silver negative image is solved and eliminated
- Second exposure
- Second developpement, the image is positive
Example (from Mr Marchesi book) with Ilford products, but this method could be applied
easily to other products:
- Ilford Pan F film exposed at
- First development (8min at 20°C/68°F):
PQ Universal 1+4 added with 30ml/litre of 10% (100gr and water to make 1 litre) potassium
Add this solution only right before developing, such developer has a limited life.
- Intermediate wash (5 water changes)
- Bleach (5min at 20°C/68°F):
Potassium dichromate 5g (Caution ! Dichromate is carcinogenic and can cause severe burns)
Water to make 1000ml
Concentrated Sulfuric acid 5ml (Caution ! Sulfuric acid can cause severe burns, add it
- Intermediate wash (2 water changes)
- Clearing (time until complete clearing):
Anhydrous sodium sulfite 50g
Water to make 1000ml
- Intermediate intense wash during 5min
- Second exposure: take out the reel and expose it with a 500W lamp during 1min30s minimum
- Second development (at 20°C/68°F):
PQ Universal dilution 1+4 for 5min or
PQ Universal dilution 1+9 for 8min
(WITHOUT potassium sulfocyanide !)
- Intermediate wash (2 water changes)
- Fix as a normal film
- Wash as a normal film
- Dry as a normal film
A first example using a chemical inversion can be found in publication
Kodak J-1 (20MB !).
Another example for TMax 100/400 films (both 35mm & 120) published in the
Mar/Apr 1988 issue of "Darkroom & Creative Camera Techniques" and posted
on rec.photo.darkroom by Paul Moshay:
- Water at 50°C (120°F). 750 cc
- Metol 2 grams
- Sodium sulfite, Anhydrous 100 grams
- Hydroquinone 5 grams
- Sodium carbonate, Monohydrate 60 grams
- Sodium thiosulfate, Pentahydrate 16 grams
- Potassium bromide 4 grams
- Cold water to make 1 liter
Develop 10 min at 20°C (68°F) - Constant gentle
agitation. Use once and
NOTE: you may use regular Kodak D76 or Ilford ID11 adding:
- Sodium carbonate 15 grams
- Sodium thiosulfate 4 grams
- Potassium bromide 1 gram
Per 250ml for each roll
2 Minutes in running water.
- Potassium dichromate 9.5
- Sulfuric acid 12 cc
Agitate 3 minutes. After 3 minutes the light may be turned on and the
remainder of the process can be done in white light.
3 minutes in running water.
- Water 1000 cc
- Sodium sulfite, anhydrous 50 grams
Agitate for 1 minute.
2 minutes in water
Expose film to white light of a photoflood or halogen bulb in a reflector at 1.50m (5
feet) for 2 minutes.
Film may remain on the reel. Rotate reel to insure complete coverage of film
by light. Do not use sunlight.
Dektol 1:2 for 3 minutes
5 minutes in regular hardening fixer.
clear, wash & dry as usual.
The time for first development should be thought of as a starting point.
The first development is the most critical part, so try to keep all the
variables, time and temperature, as constant as possible.
Expose and develop a test roll or two of film to arrive at a time and exposure
index that is suitable for your system.
TMax 100 and TMax 400 can be rated
at about its full speed but will have to be customized for your conditions.
In order to obtain
Sepia toned slides, instead of the Dektol, the second developer may be composed
of 2 grams per liter of sodium sulfide (not sulfite).
By copying a negative on a negative film, you'll obtain a positive.
To compensate the low contrast of the original negative, gamma around 0.6, you must use a
film and a processing giving a high contrast: gamma around 2-2.5.
For B/W negatives, an ortho or blue-sensitive only film is sufficient.
For color negatives, a panchromatic film is better.
The only conditions for the reproduction film are: high contrast, clear base and, of
course, good definition.
To expose, you can use two methods:
- the original negative is not modified, so prints are still easy and no risks
for the original
- no limitations in the choice for the original film (including color)
- easy and without risks contrast modification by adapting the process
- loss of quality due to the duplication
Example of film/chemicals valid both for contact or repro-
Among the specific films intended for this use, the Kodak
Fine Grain Release Positive Film (5302), a blue sensitive film
that can be manipulated under usual (amber) inactinic light, developped in D-76
(normal contrast) or Dektol (higher contrast). Sensivity of this film under a light rich of blue (fluorescent tubes) seems to
be around 6 ISO.
Here are some other combos that could be used:
I used pretty often the Agfa Ortho 25, an orthochromatic film to be manipulated under red safelight, exposed at 8 ISO developed in a paper developer
like D-72 (or Dektol) during 4 min at
This film is unfortunately no more produced, when I'll be out of stock, I'll
probably switch to the Macophot Ort 25 or Kodak
Technical Pan (2415), a panchromatic film to be manipulated
in complete darkness, probably developed in D-19 or Dektol:
|2.40 to 2.70
||4 to 7
||100 to 160
|2.25 to 2.55
||2 to 8
||100 to 200
|1.20 to 2.10
||HC-110 (Dil B)
||4 to 12
||100 to 250
|1.25 to 1.75
||HC-110 (Dil D)
||4 to 8
||80 to 125
|1.10 to 2.10
||6 to 12
||64 to 125
|1.00 to 1.50
||8 to 12
||32 to 50
|0.80 to 0.95
||HC-110 (Dil F)
||6 to 12
||32 to 64
|Low 0.50 to 0.70
||5 to 11
||16 to 25
We place the negative on the copy film, emulsion against emulsion and we expose it with
an enlarger by example.
- no special equipment
- reduced quality loss
- ideal for low volumes
- difficult to determine exposure
- increased dust problems
- low volumes only
We copy the original negative through a camera, below, macro lens and a repro
For purists, a true reproduction equipment with a special lens otimized for 1:1 ratios
gives a better image quality but this equipment is pretty expensive if you need it only
for a limited usage.
- ideal for big volumes
- easy exposure
- cropping possible
- greater loss of quality
- specialized equipment necessary