> "Removing extra emulsion from a print in "automatic" (or ostensibly
> automatic) development without leaving a demolition site behind is
> difficult to impossible, because the emulsion is *extremely* delicate
> before it has dried and the lightest touch can destroy all "photographic
> quality." (That is if it's been exposed lightly enough for automatic
> development.) "
Terry replied:
> But with the right combination of exposure and sensitiser the gum
should be hard > enough to achieve the same effects as 'automatic'
development with brush or > other forms of mechanical development.
Not true. Terry, you are still in deep denial about the difference between
"automatic" development and development by abrasion.
If you rub, wipe, swab, hose, spray or brush a print on smooth paper, you
wipe off your high tones. If you do it on rough paper, you lose the smooth
velvety tones of auto development -- getting a grainy or textured effect.
While you can no doubt mitigate that graininess by subsequent
superimposed exposures, that's a different operation.
> As to bubbles leaving uncleared patches, this is a good indicator of how
> effective water is as a clearing agent, I put a line of pennies, seven on large
> prints, arranged down the middle of the back of the print with wider spacing
> towards one end so that the print floats face down with a gradient in all
> directions so that bubbles cannot gather.
Very ingenious -- tho perhaps in US it would have to be quarters (our
pennies being too small?).>
> "However, if you use the currently popular one part gum to two parts
> ammonium dichromate formula, your emulsion may well be much harder when
> dry."
>
> That is a waste of dichromate and it reduces the strength of piment in the coat.
> Why do people do it?
Because the modern books tell them to. Why is that? Who knows? The
practice may have begun during the period of exposure by sun. Since the
larger amount of dichromate is faster, the print could be made before
conditions changed, or on cloudy days...
Judy