Re: Re[2]: Konica Reticulation

[Wayde Allen <allen@xxxxxxxxxxxxxxxx>]

On Wed, 21 May 1997, Goff Photo wrote:

> At 12:02 PM 5/21/97 EST, you wrote:
> >I wonder if someone could tell me what reticulation is?

Cracks in the gelatin layer.  If you've seen how mud dries you should get
the idea.

> >Peter B
> >(to differentiate from another Peter on the list)
> >
> >Retic. is the result of the migration of silver particles through ruptured
> gelatin cells into clumps that appear as 'graininess'. It is caused,
> usually, by thermal shock. If all solutions are not held to within a few
> degrees, including the wash, then the gelatin cell walls may rupture. (As
> you may know, the light sensitive silver halide particles are suspended in
> gelatin.)

Thermal shock is correct, the rest of this is not.  Gelatin is a protein
colloid meaning there are no cellular walls to rupture.  The mechanism you
describe is not correct unless I missunderstand your use of the word
"cell".

It is my understanding that the cracking (reticulation) of the gelatin
layer is due to mechanical stress caused by uneven swelling (this is the
mechanism used to make collotypes) or thermal shock. The stress causes the
gelatin film to crack, but there are NO cells to rupture.  Take a look at
the bottom of a dried up mud puddle and you should get the idea.

- - Wayde
  (allen@xxxxxxxxxxxxxxxx)


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