Tube-based sheet film development
Pete Bergstrom
sheet film development. I'll also be posting it to the photo-l mailing
list where it's also been discussed.
Comments and suggestions are welcome.
Pete
Making your own sheet film development tubes
============================================
The basic requirement is to select tube stock that is large enough to
hold a sheet of film without covering up any of the emulsion. For this
reason, tubes for 4x5, 5x7 and 8x10 sheets are of different size. Use
pipe of diameter 1.5 inches, 2 inches, and 3 inches, respectively, for
these sheet sizes. (If you want to find out precisely which is the
minimum, divide the short dimension of the film by pi (~3.14) to find
the pipe diameter.)
For a given developing tube, you will ultimately have two components:
a main body and a plug which will hold developer solution before
development begins. To use the tube, you curl the film and insert it
into the main body tube, add the developer and then plug the open
end. The plug has space to hold the developer solution until you tip
the assembled tube and begin development.
For each film size, you'll have different lengths of tube. The main
tube will be cut from the tube stock and sized to hold the film sheet
and the plug will also be from the tube stock but sized to hold the
necessary amount of developer.
The main tube will have an end cap and a pipe coupler glued onto it;
the plug will have an end cap glued onto it. The whole thing looks
like this:
Plug Main tube
+-----+ +-----+ +-----+
| |------+ | |-------------------------------------| |
| | | | | | |
| | | | | | |
| | | | | | |
| |------+ | |-------------------------------------| |
+-----+ +-----+ +-----+
^ ^ ^ ^ ^
| | | | |
end | coupler tube end
cap | stock cap
|
tube
stock
Tube stock sizes (in inches):
Main tube Plug
4x5 6 2
5x7 8 2 1/2
8x10 11 2 1/2 - 3
Glue the caps and coupler on the appropriate tube sections. Make sure
you *DON'T* glue the plug to the main tube inside the coupler! It is
intended to be a friction-based seal.
Cost to make the tubes
======================
The materials all have to be either black or gray schedule 40 PVC pipe
- don't buy the white or translucent pipe because it isn't
light-safe. The pipe stock is sold in 10 foot lengths, so I have
enough to make 12 4x5 tubes.
Material Quantity Total Cost
-------- -------- ----------
PVC pipe 10 feet $3.50
End cap 2 $3.00
Coupler 1 $0.19 (really)
PVC Cement 1 $1.80
Hacksaw 1 $3.00
Sandpaper 1 package $2.50
So it cost me $13.99 for the first tube and $3.19 for each one after
that.
Loading the tube
================
Before putting the film in the main tube, put the measured amount of
developer in the plug and set it aside. You'll attach it to the main
tube in the dark and from there on the development can be in daylight.
Turn out the lights.
To insert the film in the main tube, curl it in your hand, emulsion
side inwards and with the curl along the short side. Slide it into the
tube so that there remains a small (1/8 inch) edge of film that isn't
fully inside the main tube's pipe stock. This edge is important to
getting the wet film out later, although you can still retrieve it if
you have nimble fingers.
Turn the main tube so that the opening is downwards and attach it to
the plug. Keep the film oriented this way so that the developer won't
get on the film until you're ready! If you bought the right end caps,
you can stand it on end until you're ready to begin developing the
film. I generally load all the tubes I have at once and then process
them in pairs until I've gotten them all done.
Processing using tubes
======================
Tubes have some advantages to go along with their disadvantages. IMO,
the most significant advantage if you're trying to control your
processing is that you use developer quantities in proportion to the
film being processed. That is, the amount of developer per sheet of
film is constant. If you use a Jobo or other kind of tank, you only
get this consistency with a full load of film. (I usually want to
process only a few exposed film sheets at a time - that's a good day's
work.)
For 4x5 film, use 2 (US) ounces of developer, for 5x7, use 4 (US)
ounces, and for 8x10, use 8 (US) ounces. If you want to use developers
that are highly dilute (Rodinal at 1+100?), lengthen the end plug's
tube.
I've found that there are a few disadvantages to using tubes and they
may prove significant to you. First, it's not difficult to damage the
film as you're removing it from the tube - the emulsion is soft and
vulnerable at that point. (You also have the scratching problem with
tray development, but tubes only really have one time of stress.)
Second, agitation must be through continually spinning the tube. This
means that you can't expect to get compensating development to work
quite the same as tray or tank development. The spinning isn't a real
problem because you just float the loaded tube in a tray of water and
keep it spinning.
You'll need to have 3 trays for holding the developer, stop bath, and
fixer. Fill the first tray with enough water to float the tube(s). To
start development, bring the tube over to the water bath area (keeping
the tube vertical!). When you're ready to begin development flip the
tube on its side and begin spinning it in the water bath. Keep this
going the entire development time along with occasionaly end-over-end
flips to mix up the developer. Immediately after the development is
complete, remove the plug, dump out the developer and immerse the tube
in the tray of stop bath. After the stop bath, immerse the tube in the
fixer. After a couple of minutes (I fix for 8 minutes), gently remove
the film from the tube and complete the fixing in the tray.
You need to be in complete darkness from just before you remove the
plug to pour out the developer until at least halfway through the
fixer time.
I usually process two tubes at a time. It's important to allow for the
time to unplug, dump and immerse each tube in the stop bath. The best
way is to add 10 seconds to the development time for each extra tube
beyond the first, start one tube when you turn the timer on and start
the next tube when 10 seconds have elapsed. Keep track of the order
you started the tubes and remove them at 10 second intervals at the
end of the development time so that the last tube started is put into
the start bath when development time elapses.
Development times
=================
Since you're constantly agitating the film, you can expect slightly
shorter development times. In my film testing I found that Tri-X in
Zonal Pro's Gamma Plus developer developed to the correct Zone VIII
density in 6 1/4 minutes at 75 degrees F versus the recommended 12 1/2
minutes at 68 degrees F. (This is a welcome change too - spinning
tubes for 12 minutes at a time isn't any fun at all!)
If you need more information, I recommend getting hold of the original
source (listed below). Phil Davis does approach photography with a
stronger tendency towards sensitometry than I do, but I'm certainly
impressed with his results.
Beyond the Zone System - 3rd edition
by Phil Davis
ISBN 0-240-80193-8
Publisher:
Butterworth-Heinemann
80 Montvale Avenue
Stoneham, MA 02180
Barry Sherman
> [ Really excellent discourse on making and using BTZS tubes ]
>Tubes have some advantages to go along with their disadvantages. IMO,
>the most significant advantage if you're trying to control your
>processing is that you use developer quantities in proportion to the
>film being processed. That is, the amount of developer per sheet of
>film is constant. If you use a Jobo or other kind of tank, you only
>get this consistency with a full load of film. (I usually want to
>process only a few exposed film sheets at a time - that's a good day's
>work.)
I did some experimenting with this after I got a Jobo Expert Drum,
which is how I currently develop 4x5 sheet film. John Sparks relayed
the recommendations of John Sexton on how to use these drums. Mr.
Sexton recommended always using one liter of developer and that
if the drum is not loaded fully with film, one should insert one
sheet of fully exposed (like to daylight) "junk" film for every
two sheets less than a full load being processed.
Thus, in my 3010, which holds 10 sheets, if I were processing
4 sheets of "real" film I'd add 3 sheets of fully exposed junk
film.
I wasn't thrilled at the prospect of wasting this film and so
tried simply dividing the 1 liter of chemistry by 10 to get
a quantity of 100 ml per sheet of film. Since the drum requires
a minimum of 210 ml chemistry, I started off using 2 sheets
of film with 250 ml of chemistry. I developed two such sheets.
I'll call this the Inexpensive Method.
Then I tried doing it the John Sexton way, using 1 liter of
chemistry, two sheets of "good" film and 4 sheets of fogged
film. I'll call this the Expensive Method.
The result was that those developed using the Expensive Method had
noticibly higher contrast than those developed the other way.
I don't know the exact Zone VIII densities off the top of my
head, but the difference was significant. This argued strongly
against the repeatability of the Inexpensive Method.
Result? I now use the Expensive Method. Often I do have film
where I made a mistake in loading or shooting and I always save
these errors for use as "filler" sheets. When I don't have
such sheets I use Kodalith sheets. This is relatively inexpensive,
costing about $40 for a 100 sheet box. At 40 cents per "filler"
sheet, the worst case is spending $1.60 for "filler" sheets for
one development run.
Given that I rarely develop b/w film more often than once a month
and that I rarely have more than three "partially empty" development
runs per development session (I.e. it's rare that I have development
beyond the range of N-1 through N+1), that means that I'm spending at
most ~$5.00 extra per month to develop this way.
That doesn't bother me at all.
There's another option which I've not yet mentioned: using a
full liter of developer but not using the "filler" films. I've
not tried that in a quantitative test. At a certain point I just
get tired of playing lab technician and don't feel like testing
anymore.
Certainly using BTZS tubes would be cheaper, but I find the
convenience of letting the Jobo do the work combined with being
able to process up to 10 sheets at once, instead of 2, 3 or 4,
to be quite a convincing argument.
Purely a personal preference, of course.
>You need to be in complete darkness from just before you remove the
>plug to pour out the developer until at least halfway through the
>fixer time.
When I first read Phil Davis' article about the BTZS tubes in
Darkroom Techniques, he suggested that it's safe to operate
completely in daylight, uncapping the tubes and quickly immersing
them in stopbatch and then into fixer.
Has this procedure now been changed?
Barry
--
Barry Sherman, Amdahl Corp. | Over thar! The great white whale!
b...@oes.amdahl.com | Moby Rush!! He blows! He spouts! He spews!
My opinions, not Amdahl's | (almost) Herman Melville
GLSmyth
b...@DUTS.ccc.amdahl.com (Barry Sherman) writes:
>>>>You need to be in complete darkness from just before you remove the
>plug to pour out the developer until at least halfway through the
>fixer time.
When I first read Phil Davis' article about the BTZS tubes in
Darkroom Techniques, he suggested that it's safe to operate
completely in daylight, uncapping the tubes and quickly immersing
them in stopbatch and then into fixer.
Has this procedure now been changed?<<<
No it hasn't. I unscrew the cap with the tube in a position where the cap
is on the bottom, and, with the safelight on, lift the tube off the cap
and place it directly into the stop bath. After about 15 seconds of
rotation in the stop bath I remove the sheet and place it in the fix.
Then I can turn the lights on. I can't afford a Jobo and have found the
BTZS tubes to be a blessing in terms of only having to use 2 ounces of
developer per sheet. I will be making my own tubes for processing large
sheets of paper, which I'll use in the same manner.
george
Pete Bergstrom
BS> Result? I now use the Expensive Method. Often I do have film
BS> where I made a mistake in loading or shooting and I always save
BS> these errors for use as "filler" sheets. When I don't have
This sounds like a good use of the error sheets - I've had a couple of
misloads that were found after exposure when I put the dark slide back
in.
BS> such sheets I use Kodalith sheets. This is relatively inexpensive,
BS> costing about $40 for a 100 sheet box. At 40 cents per "filler"
BS> sheet, the worst case is spending $1.60 for "filler" sheets for
BS> one development run.
Besides the repeatability that I crave, I'm just too darn cheap to
bring myself to intentionally "waste" *any* film!
BS> There's another option which I've not yet mentioned: using a
BS> full liter of developer but not using the "filler" films. I've
BS> not tried that in a quantitative test. At a certain point I just
BS> get tired of playing lab technician and don't feel like testing
BS> anymore.
I've deliberately made the assumption that developer becomes
progressively less effective during development and that its effects
can only be (theoretically) identical for two pieces of film if they
are exposed and processed identically. Therefore, the only way I can
have a high level of confidence that one image has been developed
identically to another is if they are processed separately under
identical conditions.
In the future, I expect I will relax a tiny bit and start using a Jobo
tank - but still only with full loads of film.
BS> Certainly using BTZS tubes would be cheaper, but I find the
BS> convenience of letting the Jobo do the work combined with being
BS> able to process up to 10 sheets at once, instead of 2, 3 or 4,
BS> to be quite a convincing argument.
I understand - I just have a lower volume of film to process. (It's a
relatively long process for me to make a photograph - because I want
to work that way.)
>You need to be in complete darkness from just before you remove the
>plug to pour out the developer until at least halfway through the
>fixer time.
BS> When I first read Phil Davis' article about the BTZS tubes in
BS> Darkroom Techniques, he suggested that it's safe to operate
BS> completely in daylight, uncapping the tubes and quickly immersing
BS> them in stopbatch and then into fixer.
BS> Has this procedure now been changed?
I believe Phil has indeed changed his recommendation on this.
As I understand the issue, there will still be some unexposed emulsion
after development. If this emulsion is exposed to light but not
developed (possibly because the stop bath deactivated the developer)
it should be dissolved in the fixer (because it's not been reduced by
development) and there's no problem.
However, if some developer is still active and the emulsion is
exposed, you'll get solarization (the film grain is triggered and the
developer reduces it to metallic silver) and therefore your negative
will be altered. (Sometimes this is good, of course.)
Since I don't have control over this exposure, I don't take the chance
at all - work is done in darkness until I'm absolutely sure that
random light won't derail my work.
Pete
(Barry, it looks like your newsreader changed followups to rec.photo.
Did you mean this to happen?)