Re: Reversal processing for enlarged negatives

Hi Loris,

Glad you're persevering! One thing I found with reversal is that I
DIDN'T get pinholes. Spots from dust occasionally, but not the kind of
pinholes normally associated with lith film. The graininess you speak
of - does it look the same on every film, regardless of magnification,
or is it simply *amplification* of grain present in the original neg
(which you'd have to put up with)? You state that it's worst in the
dense areas, but how dense? Do the grainy areas correspond to the
grainiest areas of your 35 mm original (graininess normally appearing
worst in the midtones)? My guess is that it may be due to your not
using a black (or yellow/orange/red) card under the film - for exposure
under the enlarger as well as flashing. If your easel is like mine, it
is not perfectly smooth but has a kind of eggshell texture, and
contrasty film can easily pick this up is light is reflected back up
from it.

As for high base fog, this is almost certainly not due to your lack of a
black card. Without the card absorbing light, the film is receiving
MORE exposure, and because you're using a reversal process everything is
back to front and more exposure gives you a lighter/clearer negative. I
expect, though, that a black card will improve the graininess and also
improve the sharpness/clarity of your negs because light reflected up
from the easel is unfocused, so the card is definitely worth using. To
lower your fog level, I suggest increasing your first development time,
and the enlarging exposure time as well if this doesn't do the job. If
you find that the foggy negs were made later during the printing
session, you're probably overworking your developer.

I'm slightly confused by Ryuji's suggestion of using KRST as a
redeveloper, if I've understood him right. In toning experiments many
years ago I did try redeveloping bleached prints with selenium
(home-make Kodak T-56, not KRST... or is selenium T-55?) and I seem to
remember that stock strength solution would eventually yield a soft,
brownish image if allowed long enough to do so (a very long time!), but
I can't imagine it being any use in reversal, other than by toning to
strengthen an otherwise finished neg. On the other hand, it was a very
long time ago and I don't remember if I was using some weird bleach, so
maybe I'm wrong... in which case apologies to Ryuji. Has anyone tried
this?

Ryuji's other suggestion of flashing from the backside as well sounds
kind of sensible, but really isn't necessary for the simple reason that
the flash time is determined by test strip and if the film ain't getting
enough light we can give it more time. If you refer to the little
doodles on P.42 of Post-factory 2, you'll see that exposure and the
initial development create a silver positive image at the surface of the
emulsion layer; this is removed in reversal and the remaining silver
halide that is fogged and redeveloped exists underneath the original
black silver, next to the film base. If you also flashed the film from
the back, you'd end up with a negative image which "floats" above the
base and below the surface. No harm in that, I suppose, but not point
to it that I can see, either.

As for different films and developers, I found lith film almost perfect
for reversing, presumably because of its high contrast. I didn't try
many contone films, but I didn't find any particularly good for my
purposes. It depends what sort of D-max you want. With lith, the
problem is to tame the high contrast and a "flash" exposure was my way
of achieving this, but with contone films you'll get the opposite
problem of low contrast which you'll need to boost if you're
contemplating Pt/Pd, VDB &c. Technical Pan in 35 mm was the best that I
tried for reversal as far as I remember (the slowest films generally
being inherently more contrasty); Gravure Positive in 5X4 (now
discontinued?) was another that I tried, but as far as I can recall this
wasn't too successful. Ilford Ortho (which was renamed Orthochromatic
Plus; don't know if it's still going) was a contone sheet film available
in relatively large sizes. I found it bloody useless for reversing,
due, I believe, to its thick emulsion; it was just impossible to develop
right down to the film base. A friend did report good results with it,
however... but he never showed me any, nor explained exactly how he
achieved them!

Someone suggested D-19 + thiocyanate with some camera film or other
(that message went to the machine downstairs). This may be satisfactory
if it yields sufficient D-max for you, but not all films are suitable
for reversal. You're most likely to be successful with the slowest.
But my experience is that you can get excellent continuous tones by
reversing lith, without pinholes, and should be able to do so by paying
attention to details and asking more questions if necessary. If films &
chemicals are hard to obtain where you are, I'd abandon lith only as a
last resort.

Finally, the big black dots that you mention. "Dunno" is the short
answer, but since you're doing reversal, black spots are due to
something blocking the light - could it be crud on your 35 mm negative?
(Of course in neg-pos processes dirt on the neg would produce clear
spots.) Another possibility is air-bells sticking to the film during
the first development. If they're present during the whole of
development they'll result in black spots, but if they're dislodged half
way through they'll produce dark spots, but probably less than full
black.

Good luck,

Liam

P.S. Oh yeah, I'm grateful to Ryuji for his comments on the pH of the
clearing solutions. The dichromate clearing solution (50 g sulphite in
1 litre) was based on a Kodak formula (which I think may have been
R-21b), but the Kodak formula included 1 g of sodium hydroxide. I
didn't understand the reason for it and my tests seemed to show it
wasn't necessary, so I left it out! The water here is mildly alkaline,
but maybe it would be a good idea to put the NaOH back in if you do have
acidic water.

-----Original Message-----
From: Liam Lawless [mailto:liam.lawless@blueyonder.co.uk]
Sent: 24 March 2004 20:41
To: lawless
Subject: Fw: Reversal processing for enlarged negatives

----- Original Message -----
From: "Loris Medici" <loris_medici@yahoo.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Wednesday, March 24, 2004 10:45 AM
Subject: RE: Reversal processing for enlarged negatives

> Hi Liam, thanks for contributing!
>
> > -----Original Message-----
> > From: Liam Lawless [mailto:liam.lawless@blueyonder.co.uk]
> > Sent: Wednesday, March 24, 2004 4:16 AM
> > To: alt-photo-process-l@sask.usask.ca
> > Subject: RE: Reversal processing for enlarged negatives
> >
> >
> > I tried sepia "redevelopment" a long time ago ...
> > ... but it was completely opaque to UV ...
>
> Then this is not good for alt. process printing. What about KRST
> toning? Will be KRST toned negastives suitable for alt. process
> printing? Will KRST provide any advantage over Dektol / Bromphen or
> Multigrade print developers (for redevelopment)? I liked Ryuji's
> point: "you will redevelop more completely with KRST: tiny grains
> that't won't fog in room light and won't develop in the second
> developing solution (say... in Dektol and such developers), will be
> developed with the toner". What will be your comments on this?
>
> > ...
> > I also tried D-19 + thiocyanate for first development, as per
> > Kodak's insructions for reversal of Panatomic-X (for which D-19
> > without thiocyanate was recommended for the 2nd. dev.)
> > Again, the exact details are a little hazy now, but I seem to
> > recall that while thiocyanate made a useful difference when
> > reversing camera films, it didn't confer any particular
> > advantage on lith films. As a silver halide solvent,
> > thiocyanate assists in achieving clear shadows, but lith film
> > is so contrasty that it doesn't need this assistance as long
> > as the exposure and development time are adequate. And I
> > also found that lith film gave much better reversal negs than
> > contone film.
>
> My problems with lith negatives are: I see very ugly big black dots
> here and there and general grain clumping in dense parts of the
> negative
> (everytime) and I have high base fog (sometimes - I guess the high
base
> fog is caused by the fact I don't place a black sheet under the
> negative). What can I do to have smoother tonality? (please note that
I
> use 35mm film - not medium format, so my enlargements are around 8x -
> 10x scale)
>
> Thanks in advance,
> Loris.
>
>
Received on Wed Mar 24 21:16:29 2004