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Flanagan
                Photographic

Fine-Art Black & White Photography
in classic styles and materials

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A Few Words About
Archival Print Processing  

Traditional photography relies on the light sensitivity of compounds based on silver plus chlorine and/or bromine, which make a salt.  Tiny grains of this salt are distributed in gelatin to make an emulsion.  When light strikes the emulsion, the silver compound changes chemically.  The more light, the bigger the change.  A chemical bath (the developer) reacts with the exposed salt grains, turning them to metallic silver grains, which are black to the eye.  These grains form the image.  The more light and/or development, the darker the emulsion.

Basically the same process occurs in film and printing paper, only the substrate is different.  Printing paper has a  white coating under the emulsion, to boost the brightness of highlights.  Film is necessarily clear to allow light to shine through when making prints.  Both substrates to carry a thin coating of the silver-gelatin emulsion.  Yes, it's the same gelatin found in desserts, extracted from bones, but treated to make it much tougher, physically.  For example, an acid bath hardens the gelatin to resist scratching.

After development, the emulsion still contains all the original grains;  some have been converted to black silver, some are still in the form of the salt.  "Fixing" the image dissolves the salt grains, removing them from the emulsion, so only the developed  grains remain to form the image.

Potential problems:
  1. Failure to remove all the undeveloped grains.  Over a long time they may revert to metallic silver, creating unwanted black areas in the image.
  2. Failure to remove the fixer, the chemical that dissolved undeveloped grains.  An acid, fixer may corrode the black silver grains to make them invisible, weakening the image.
  3. Chemicals in the atmosphere corrode silver grains, destroying the image.
Archival processing addresses all three threats.
  1. Thorough fixing ensures full removal of undeveloped grains.
  2. Additional chemical treatment and washing remove almost all fixer (a slight trace actually stabilizes the image).
  3. Toning the image to "armor" the silver grains for protection from later attack by chemicals.
Toning coats each silver grain with a chemically bonded layer that resists later chemical activity better than pure silver.  Toning may or may not be visible. 

Selenium is our standard toning material, applied as a "final bath" in the darkroom process.  When used to enhance longevity, selenium darkens the image slightly, increasing contrast.  When left in the selenium solution for longer times, prints take on a "warm" tone, shifting from a neutral black.  Extended toning changes the color of the developed grains from black to reddish brown, giving prints an "antique" appearance that in the past resulted from aging or toning.

To finish its protection, a print is mounted on a stiff board that resists folding and tearing.  The mount also prepares a print for framing.

When framed under glazing , a print must not be placed directly  against the glass or acrylic.  To separate the print from the grazing, a mat board is placed on top of the mount, with a window cut our to reveal the print. 

For full archival treatment, mounts, mats, the adhesive that holds the print to the mount, and the frames must all be free of acid.  Wood frames are lined with a separator to prevent anthing in the wood from migrating through the mount to the print. 

If our prints don't last 100 years, we'll make another one for you. ;-)


Why Film?

  A  medium format black and white negative (2.25 inches square or slightly larger) contains as much information as a 90 megapixel digital image.  Large format negatives exceed 200 MP.  

This high resolution allows prints larger than 16x20 inches to appear sharp even when examined from close up.
Modern film, on a base of polyester, lasts as long as prints.  That's good for making prints later--no worry about a digital storage medium growing obsolete and unreadable.
 
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Flanagan Photographic
A service mark of W. A. Flanagan, Inc.
Ph:  +1.703.855.0191   
Fx:  +1.703.242.8391
Mail to Lockbox 411, Oakton, VA 22124