Wednesday, February 22, 2017

HOW TO OBTAIN THE SHARPEST BLACK AND WHITE PHOTOGRAPHS





Leica M6, 90mm f/2.8 Elmarit, Agfapan APX 100, Agfa Rodinal 1:100


From time to time I have inserted some of my own black and white photographs in articles and more often than not readers have asked what films and developers I use.  To answer that question let’s look at films and developers in general first.

Any film emulsion uses silver halides as the light sensitive agent.  The larger the silver halides, the more sensitive the film is to light.  When film is developed, the image is formed by clumps of silver halides which show up as grain when enlarged.  Since faster, more light sensitive films start out with larger silver halides, the resulting grain clumps are larger as well.

Considering that it is the grain clumps which make up the image and its inherent detail, it stand to reason that a fine grain film should be used to obtain as much detail (sharpness) as possible, which means using a film as slow as possible under the light conditions where the photographs are taken.

Since the grain clumps are formed during the developing process, it should be obvious that developers will make a definite difference as well.  To make the grain smaller, some developers use a silver solvent.  While this results in smaller grain, this also results in softer edges of the grain clumps which will lead to the appearance of less sharpness.

 
An extreme example of high acutance over small grain detail  

To avoid this, some developers are formulated for high acutance.  While this will lead to a slight increase in grain size, it also increases the edge sharpness of the grain substantially with the result of much sharper appearing images.

It sounds like a contradiction to use a developer with high acutance (increasing the grain size), if we want to obtain the sharpest images possible.  However, when combining a high acutance developer with a fine grain emulsion, the results can be amazing.

One such developer is Agfa Rodinal or one of its resurrections, ADOX  Adonal/Rodinal.  In the late 60ies the original ADOX factories were sold to DuPont. They later sold it to Agfa. With the closure of Agfa´s consumer imaging branch in Leverkusen 2005 ADOX became engaged in manufacturing again trying to save as much knowledge as possible and transfer it to a smaller level of production.  ADOX successfully brought back Agfa’s MCP, MCC, APX (Silvermax) and the entire Agfa B/W chemical line.

Scan of the full negative
Leica M6, 50mm f/2 Dual Range Summicron 
Agfapan APX 25, Agfa Rodinal 1:100

Cropped section of the same negative

Further crop of the same negative

Final crop from the same negative
The full image would be 35 x50 inch, 85 x 130 cm in size

My favorite films were the Agfapan APX 25 and APX 100.  They disappeared from the market with the demise of the Agfa consumer imaging division.  But they have been resurrected under the ADOX Silvermax label.

Since these are very fine grained films to start with, a high acutance developer like ADOX Adonal/Rodinal presents no problem.  You will still end up with amazingly fine grain and with the added advantage of high acutance, meaning very fine grain, very sharp negatives.  In addition, the ADOX Adonal/Rodinal must be used with a high dilution, which makes the developer very economical as well.

Most recommendations are to use a dilution of 1:50, developing with constant agitation for 30 to 60 seconds and 5 to 10 seconds for every 30 or 60 seconds thereafter.  For myself I used a modified developing process starting out with a dilution of 1:100.  Instead of manual agitation, I used a Jobo film developing drum on a Beseler motor base with continuous agitation for 15 minutes.  This gives the assurance of completely even agitation because the base reverses direction approximately every 2.5 rotations.  In addition it gently rocks the developing drum from side to side.  Another advantage is that one does not need to stare at a timer for 15 minutes.

Leica M6, 135mm f/2.8 Elmarit, Agfapan APX 25, Agfa Rodinal 1:100


Enlarging the negatives with a Leitz V35 enlarger has given me results that rival enlargements made from medium format negatives.


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