Light leak or agitation problem?
John Boyes
I have encountered a curious problem and I'm hoping someone can help me find
a cure! I develop lots of B&W roll film (normally FP4 or Tri-X), using ID11
at 1+1 and Hypam fix. Some of my rolls (about 60%) are showing a dark area
to both sides of the negative - about 5mm in on a 6x6 neg. This results in
a problem when printing full frame as the sides of the neg are about half a
stop lighter than the rest of the neg. The "fading" on the print is a
subtle graduation, not a hard line.
Now this does not happen on 40% of my negs yet I develop all films in the
same way at the same temperature with the same agitation! It NEVER happens
on 35mm film.
I use a plastic tank (fairly new) and plastic spirals. I use the twizzle
stick to rotate the film during development (10 secs every minute etc.) I
don't invert the tank. Fresh dev is always used, sometimes the fixer is
used for 2-3 films.
I thought at first it was light leak from the camera back, I use a Hassy
503CW & A12, BUT on checking old contact sheets and negs I found that it
also happened when I had an RB67 so I figure its not a problem with the
camera(s). Any E6 or C41 I do is always commercially processed and there's
not a problem with those images.
So it seems that I have an intermittent problem here and its not immediately
obvious what is causing it. Any help would be greatly appreciated. Thanks
John
Huib Smeets
My experience with tanks is that only rotating the spiral isn't enough for
even development of the film. I had to conclude this after doing the same as
you did: no inversion, only rotating. Rotating gave me a very uneven
development (120 roll of tri-x in D76).
Just give inversion followed by a firm tap on the workspace a try as all
film datasheets/leaflets recommend this.
Greatings,
Huib Smeets
Netherlands
"John Boyes" <john.i...@cwcom.net> wrote in message
news:ykJY5.12127$Ig.53445@news1-hme0...
John Boyes
I'll perfect my Tom Cruise "cocktail" technique over Christmas!! :-) Many
thanks.
John
"Huib Smeets" <hsm...@plex.nl.removethis> wrote in message
news:97644833...@WHIRLwind.plex.nl...
John Hicks
<john.i...@cwcom.net> wrote:
>I use a plastic tank (fairly new) and plastic spirals. I use the twizzle
>stick to rotate the film during development (10 secs every minute etc.) I
>don't invert the tank.
That's the problem. Not only do plastic reels tend to cause the
excess edge density, your agitation method is making the problem
worse.
Actually what you're seeing isn't excess edge density; the center
area is underdeveloped compared to the edges, where the reel spiral
causes a bit of turbulence.
Use a double-size tank, put a reel loaded with film on the bottom
and an empty reel on top. Use just enough developer to cover the
bottom reel. Invert the tank continuously for the first 30 seconds,
then twice every 30 seconds. Gently does _not_ do it; vigorously does.
---
John Hicks
Doug Edington
created and drove myself crazy. I had the same problem (I think) with Tri-X.
I, too, have been shooting Tri-X and developed and printed mostly B/W sport
action photos for a lot of years. After a fairly lengthy period of
inactivity due to family health problems, I got back into it with fall high
school sports. I had what I thought was light sruck film and it gave me the
same printing problem you described. I trouble shot for hours looking for
light leaks with my reloadable cassettes, my film loader, and even found a
description of what my film looked like on Kodak's web pages. The problem
was caused, according to Kodak by importing inspection by X-ray and CT
scanning which increased it's power when the was a questionable display. I
got a fresh 100 ft. roll, new cassettes, fresh chemistry, shot some football
and volleyball games and had the same problem. Then, as often happens, I
remembered reading somewhere about fixing the film again to try and save the
shots. It worked. It appears that in my lengthy layoff I neglected to allow
he proper time for fixing the film. Tried fixing longer on an unexposed test
strip of film, the went and fixed a couple rolls of unprintable film and now
have excellent contast and sharpness-and some very easy printing. Are you
allowing sufficient fixing time? I've been in my darkroom for over 20 years
and still made this stupid mistake.
Doug Edington(PA)
"John Hicks" <j...@magicnet.net> wrote in message
news:3a33c8f5...@fl.news.verio.net...
Robert E. Smith
Plastic reels seem to be finicky as to agitation. I use both but prefer
the s.s. reel and tank system. I process mostly PXP and TX with
occasional TXP. I am learning to us the modern T-grain films as I am
being dragged kicking and screaming into the new Millennium. My
technique differs from Mr. Hicks slightly. I prefer to invert the tank
three times within a 6-second period every minute (30 seconds during the
first minute). Then rap the tank _hard_ on the table three or four
times thereafter. Allowing a quiescent time between inversions seem to
control grain and contrast somewhat.
Many posts here seem to indicate a hesitation to use steel reels due to
the "difficulty" of loading. Actually I fine the steel reels _easier
and faster_ to load. Maybe that is due to my early training when 120
film and steel equipment was about all we had.
dr bob.
John Boyes
time!! . I think it must be the agitation not the fixing time because I
always fix for 4 mins in Hypam 1+4 (rec 2-5 mins) using fresh stock and 5
mins with once or twice used stock. I'll post the results of my next film.
John
"Robert E. Smith" <rsm...@dmv.com> wrote in message
news:3A34E1...@dmv.com...
Colin DeWolfe
Stir your chemicals real well before you put them into the tank.
I had similar problems when I started C41, the culprit was the bottom
of my containers were in the bath while the top wasn't. Therefore the
chems were warmer at the bottom, and were also the last poured into
the tank, causing overdevelopment on one side. I solved it by shaking
the chems for 10 seconds before pouring them in.
Colin
HypoBob
The problem with rotational or twisting agitation is that the negatives near the outside of the
tank are moving much faster than the ones near the center. (The technical terminology is that
the outer ones have higher tangential velocity.) It's much like a bunch of kids on roller
skates or ice skates playing "crack the whip". The kid in the center is leisurely turning while
the ones on the end of the line are skating like mad to keep up.
Also, as John Hicks points out, the design of most plastic reels causes additional turbulence
that only exacerbates the problem.
Bob
---------------------------------------------
Jean-David Beyer
>
> John,
>
> The problem with rotational or twisting agitation is that the negatives near the outside of the tank are moving much faster than the ones near the center. (The technical terminology is that the outer ones have higher tangential velocity.) It's much like a bunch of kids on roller skates or ice skates playing "crack the whip". The kid in the center is leisurely turning while the ones on the end of the line are skating like mad to keep up.
>
the outside of the reel exposed the same as a frame at the inside of
the reel would, given the same exposure, be denser because of the
greater agitation. Perhaps this would be so if laminar flow obtained
while the developing process occurred. I have measured this and never
noticed that effect.* I normally use a Jobo CPE-2 processor at "High"
speed with the 2502 reels for 35mm film, although I have also used the
1501 reels.
With spiral reels, the problem (which is easier to describe for 35mm
film, but applies to 120 size film as well) is that the film nearest
the sprocket holes gets more development (higher density) than that in
the center (farthest away from the sprocket holes) of the film. This
would have nothing to do with tangential velocity.
When Dr. Henry was doing his tests of film, he was vexed by the
problem of getting uniform development over a strip of uniformly
exposed film, and went to heroic lengths to get uniformity, without
much success. He spent pages 132 to 136 of the second edition of his
book, "Controls in Black-and-White Photography" discussing the
problems and concludes: "... if roll film is developed on reels, there
will be increased development on the lateral edges." You can expect
about 8% to 10% variation between the center of the strip and the
edges.
___
* One of Dr. Henry's observations is that if the degree of agitation
is increased from a far too slow amount to a far to great amount, what
is observed is that the density as a function of agitation increases
up to a point and then levels off. Provided that the film with the
least tangential velocity between the developer and the film gets that
much agitation, it should make little difference.
--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ Registered Machine 73926.
/( )\ Shrewsbury, New Jersey
^^-^^ 11:00pm up 8 days, 7:48, 3 users, load average: 2.06, 2.07, 2.00
John Hicks
<jdb...@exit109.com> wrote:
>The trouble with this explanation is that it would say that a frame at
>the outside of the reel exposed the same as a frame at the inside of
>the reel would, given the same exposure, be denser because of the
>greater agitation. Perhaps this would be so if laminar flow obtained
>while the developing process occurred.
I'm inclined to agree with you; I've never observed any increased
density of frames that were on the outer spirals.
>With spiral reels, the problem (which is easier to describe for 35mm
>film, but applies to 120 size film as well) is that the film nearest
>the sprocket holes gets more development (higher density) than that in
>the center
This is where weirdness sets in. Assuming turbulence along the edges
of the rotating spiral, sort of a standing wave, causes the line of
excess density it should a) appear on both sides of the film and b)
not be present if inversion agitation or dip'n'dunk of the plastic
reel is used. In my experience, it appeared on one side only, never on
both, and was still present when different agitation methods were
used.
I've never seen it with 35mm film; the image area is never within
the spirals, just the sprocket-hole area.
---
John Hicks
John Boyes
suggestions and descriptions. I shall agitate using the methods you have
all described and hopefully it will reduce the problem!
John
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"John Hicks" <j...@magicnet.net> wrote in message
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