TRI-X ISO 400 20° C 1+50 8'30
1' prewash
best regards
Gary Marklund schreef op 17/04/15 om 22:17:
OK, You have my attention. I just went into the darkroom and I have two bottles of real Rodinal. A 500ml bottle that was opened (and probably used once) in 2005. I shook the bottle and it gurgled like it was new. The other bottle is a 125ml bottle that has never been opened, still has original Rodinal notes folded over the top of the boxed bottle).
My M6 has been screaming "Feed Me!" for some time. Like Janet, I'm interested in using it with Tri-X (also Ilford delta 400).
Comments and E.I. and development times more than welcome.
Thanks,
Gary
On Fri, Apr 17, 2015 at 1:08 PM, Gary Marklund <garymarklund@xxxxxxxxx <mailto:garymarklund@xxxxxxxxx>> wrote:
OK, You have my attention. I just went into the darkroom and I
have two bottles of real Rodinal. A 500ml bottle that was opened
(and probably used once) in 2005. I shook the bottle and it
gurgled like it was new. The other bottle is a 125ml bottle that
has never been opened, still has original Rodinal notes folded
over the top of the boxed bottle).
My M6 has been screaming "Feed Me!" for some time. Like Janet, I'm
interested in using it with Tri-X (also Ilford delta 400).
Comments and E.I. and development times more than welcome.
Thanks,
Gary
On Fri, Apr 17, 2015 at 12:45 PM, `Richard Knoppow
<dickburk@xxxxxxxxxxxxx <mailto:dickburk@xxxxxxxxxxxxx>> wrote:
On 4/17/2015 12:01 PM, Janet Gable Cull wrote:
Richard, will you describe "edge effect"? I wonder if
that's what I observed in my friends scans that I like. I
wonder how and why it would do that? Does it somehow
perceive the light and dark of an image, and treat them
differently?
Edge effects, sometimes called border effects, are
variations in development at the border of a high and low
density area. The nature of the effect depends on the
developer, specifically on whether its reaction products
suppress or enhance development. The effects are very
localized because they are due to diffusion of the developer
reaction products in the emulsion. The usual effect is to
increase the contrast at the edge. Because the effect depends
on reaction products its increased where the developer is
highly diluted or where there is insufficient agitation to
wash away reaction products at the surface and bring fresh
developer there. When the effect is not extreme it enhances
sharpness. Note that this is sharpness not resolution. Sharpness developers were long popular for 35mm use because
they tend to compensate for the lack of sharpness caused by
insufficient film and lend resolution. More modern films have
better resolution. However, the eye tends to judge sharpness
by edge contrast so a high resolution but relatively low
contrast image will look less sharp than one with high edge
contrast but considerably lower actual resolution. Extreme
edge effects can look like someone drew lines around objects. This used to be a serious problem with motion pictures because
the release print was often several generations from the
original. Each generation increased the edge effects until
one got "edge crawl". Edge effects and compensation are
related since both depend on local exhaustion of the developer.
Dome developers, notably hydrquinone, have reaction
products that tend to accelerate development while others,
like metol, tend to suppress it. Some combination developers
have little edge effect due to the mutual cancellation of the
effect by the developing agents. Nonetheless, developers like
D-76 will become edge effect developers when diluted to 1 part
stock to 3 parts water or more.
-- Richard Knoppow
dickburk@xxxxxxxxxxxxx <mailto:dickburk@xxxxxxxxxxxxx>
WB6KBL
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