Why two step fixing is a Really Good Thing

<b>Subject: Why two step fixing is a Good Thing</b>

<br><br>

While looking at the thread entitled <a href

= "http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=007bTn">Again

a purple tri-x question</a>

<br><br>

I was led to an interesting article about <a href

= "http://groups.google.com/groups?

q=two+bath+fixer+purple+author:Gudzinowicz&hl=en&lr=&ie=UTF-8&oe=UTF-

8&selm=84ek6b%247m2%241%40freenet9.carleton.ca&rnum=3"><u>two stage

fixing</u></a> ...And I <b>Highly Recommend reading it.</b>

<br><br><ht width = "120"> <br>

 

<pre> "taco*boy" <ses_2@snet.net> wrote: >Is fixer

OK to use over and over and over? I've heard that> fixer will turn

fixer purple when depleted. I have never seen this. >Am I

wasting fixer I throw it away and it's still clear?

 

The best option is to use two fixer bath fixation. The rationale

is outlined below, taken from one of my old posts.

 

 

Post Development Processing

 

©Copyright 1998 by Dr. Michael J. Gudzinowicz

 

The basis of fixation and accompanying problems aren't treated in

depth in most texts. This oversight often leads to postponed

"accidents" whenever people are tempted by a sense of false

economy to save time or materials. An introduction to the underlying

chemistry should help to define a more critical approach to film and

paper preservation, which doesn't rely on rumor and the advertising

literature. The following notes were taken from Grant Haist's

"Modern Photographic Processing, Vol.1" (Wiley, 1979),

"The Theory of the Photographic Process" edited by T. H.

James (3rd & 4th ed., 1st & 2nd edited by C. E. K. Mees;

Macmillan, 1966 (3rd)), "Ilford Monochrome Darkroom

Practice" by Jack Coote, and the research and technical

literature.

 

<b>Fixation:</b>

 

The common notion is that the fixer removes undeveloped silver halide

by a simple reaction involving the replacement of the halide by

thiosulfate to form a soluble silver complex, and then if the film or

paper looks or tests "clear", the only problem is

fixer removal. Unfortunately, this is not the case. When a film is

"fixed", a number of complexes are formed between silver

and thiosulfate, and all are in dynamic equilibrium. In addition, the

accumulation of halide during fixation reduces fixer capacity

with use when free silver and halide levels approach their limits of

free, non-complexed solubility.

 

A simple table outlining the dissolution of silver in fixer, and

equilibria with fixer is outlined below.

 

The silver halide may dissociate to a very small degree in aqueous

solutions, and the thiosulfate anion will form a 1:1 complex with the

silver cation (Rxn 1) or the thiosulfate may react directly with the

solid silver halide crystal (Rxn 1). In either case, the first

complex (I) is >very insoluble< and remains tightly adsorbed to

the surface of the solid silver halide.

 

A second thiosulfate anion may react with the first complex (I), to

form a soluble product (II) with a silver to thiosulfate ratio of 1:2

(Rxn 2); and then if "free" thiosulfate concentrations are

high, a third thiosulfate anion may react with the soluble second

complex (II), creating a third complex (III) with one atom of silver

and three molecules of thiosulfate which is quite soluble (Rxn 3).

 

 

<b>Sequence of Complex Formation:</b>

 

Note: Charge of ions is in () brackets; the # of kinds molecules

[kind of molecule]# in the complex follows brackets; TS is

thiosulfate (hypo) anion; Ag is silver; Br is bromide. <->

shows equilibrium reactions.

 

Rxn 1) Ag (+) + TS (-2) <-> AgTS (-)

 

AgTS (-) is the first complex (I) called monoargentomonothiosulate

since it contains one silver cation and one hypo anion; it is

insoluble and remains adsorbed to the crystal as it forms.

 

Rxn 2) AgTS (-) + TS (-2) <-> Ag[TS]2 (-3) (aq)

 

Ag[TS]2 (-3) (aq) is the second complex (II) complex formed by the

addition of another thiosulfate anion to monoargentomonothiosulate to

form monoargentodithiosulfate. The second complex is soluble in

aqueous solutions and is removed from the emulsion by diffusion.

 

Rxn 3) Ag[TS]2 (-3) (aq) + TS (-2) <-> Ag[TS]3 (-5) (aq)

 

Ag[TS]3 (-5) (aq) is the third complex (III) called

monoargentotrithiosulfate since it has three thiosulfate anions

complexed with one silver cation. It very soluble in aqueous

solutions.

 

In solution, these reactions are reversible, so all complexes are

present, and a small amount of Ag+ cation is not complexed in

solution.

 

The following equilibria also occur:

 

Rxn 4) Ag (+) (aq) + TS (-2) <-> AgTS(-) (aq)

 

where all components are in solution (aq) and adsorption doesn't

occur.

 

Rxn 5) AgTS (-) (aq) + TS (-2) <-> Ag[TS]2 (-3) (aq)

 

where the monoargentomonothiosulfate is in solution and not adsorbed.

However, in solution the concentration of monoargentomonothiosulfate

in this and the preceeding aqueous reactions are very low since it's

nearly insoluble.

 

Rxn 6) Ag[TS]2 (-3) (aq) + TS (-2) <-> Ag[TS]3 (-5) (aq)

 

where both the monoargentodithiosulfate and monoargentotrithiosulfate

complexes are in solution.

 

As more silver is put into solution with fixer use, more

complexes II & III are formed, and the level of the less soluble

1:1 complex (I) and free silver ion are also increased. After a few

uses of fresh fixer , the less soluble complex (I) and silver

halide are left in the paper or film at low, but destructive levels,

although the film appears to clear.

 

Also, thiosulfate is adsorbed to developed silver grains in papers

(iodide tends to displace it from films). Residual complex I and

residual thiosulfate adsorbed to developed silver grains are

converted to trithionite and higher thionites in a few days, and then

degrade and react with silver giving stains (sulfiding) and fog.

(Brown silver sulfide is seen after bleaching the silver grains, and

is proportional to the developed silver.)

 

With progressive use of the fixer, levels of bromide rise, as well as

chloride from papers and iodide from films. Silver halides have very

low solubility, and as the level of bromide or iodide rises, it forms

silver halide crystals in solution and the fixer will no longer

dissolve silver halide. A number of complexes and equilibria occur

with each halide and mixtures. On a relative basis, silver chloride

is more soluble than bromide and has little effect on fixer capacity;

silver bromide is less soluble and determines fixer activity to a

significant degree, unless films containing low levels of iodide are

fixed, in which case fixer capacity is reduced significantly

due to silver iodide insolubility (a problem with T-Max films,

treated later). In instances where silver is removed to

"regenerate" fixers, iodide accumulation may interfere.

Also, in two - bath fixation which follows, carry-over ocurs,

which requires periodic replacement of both baths.

 

The only way to ensure that little silver bromide (AgBr) or the

insoluble first complex is left in the paper, is to use fresh

fixer with little accumulated silver and halide, and an excess of

non-complexed free thiosulfate to remove it. This approach to

archival fixing when used with one fixer bath is fairly wasteful,

though effective.

 

Rather than using one fixer bath, the same results can be obtained

with two baths, and the capacity of the fixer is far greater.

Essentially, the first bath removes the bulk of the silver and

halide, and leaves traces of silver halides and the first insoluble

complex in the emulsion and paper. The amount when carried over to a

second fixer bath is insignificant in comparison to the amount of

free thiosulfate, so the second bath always acts as

"fresh" fixer with high non-complexed thiosulfate levels

to react with the small amounts of silver halide and less soluble

complexes to speed their complete removal from the emulsion.

 

 

<b>More on Fixing - One and Two fixer Bath Fixation:</b>

 

Grant Haist, the former director of research at Kodak, cites the

following maximal permissible values for one-fixerbath film and

paper fixers for commercial and archival processing:

 

One-fixer bath fixation: Commercial Archival

 

Film:

 

Max. Ag conc.: 1.5 g/l 0.2 g/l

Max rolls/gal: 25 rolls/gal 2 rolls/gal

Non-image Ag in film: 0.01 mg/in^2 0

 

Paper:

 

Max. Ag conc.: 0.3 g/l 0.05 g/l

Max. sheets/gal: 30 8x10 5 8x10

Non-image Ag in paper: 0.005 mg/in^2 0

 

Essentially, as fixer total silver (free and complexed) and halide

concentrations rise, the fixer's ability to remove all of the

silver from the paper diminishes markedly, as indicated by the very

limited capacity of one-fixer bath to remove silver to archival

levels.

 

The solution to the limited capacity is to use a fresh second

fixer bath to maintain a very low total silver level, with a

water rinse between the first and second baths to minimize

fixer/silver carry-over. Some older texts even suggest a fresh third

fixer bath .

 

 

Two bath fixation: Commercial Archival

 

Film:

 

fixer Bath 1:

Max. Ag conc.: 6 g/l 3.5 g/l

Max. rolls/gal: 60-70 40

 

fixer Bath 2:

Max. Ag conc.: 0 .5-1.5 g/l 0.02 g/l

after 60-70 after 40

 

Non-image Ag in film: 0.01 mg/in^2 0

 

 

Paper:

 

fixer Bath 1:

Max. Ag conc.: 2 g/l 0.8 g/l

Max. sheets/gal: 200 8x10 70 8x10

 

fixer Bath 2:

Max. Ag conc.: 0.3 g/l 0.05 g/l

after 200 after 70

 

Non-image Ag in paper: 0.005 mg/in^2 0

 

The first fixer gets rid of most of the silver, and the second

maintains a very low silver concentration and relatively high free

thiosulfate concentration to remove the remainder of the insoluble

complexes and non-image silver present in the emulsion after the

first fixation.

 

The first fixer bath is used for the maximum number of sheets or

rolls indicated, and then discarded after silver recovery.

 

The second fixer bath is substituted for the first, and a fresh

second bath is prepared.

 

After 5 cycles (substitutions), or one week if continuously exposed

to air in tanks, both baths are replaced. Compare the capacity for

commercial or archival standards using fixer two baths to that for

one. Two bath fixation is far more economical than using

one fixer bath , and avoids the temptation to over-use fixer which

results in under-fixation and difficult removal of insoluble

complexes which destroy prints and film.

 

 

<b>Films:</b>

 

With films, the fixation time in the first fixer should be at

least twice the clearing time... likewise for the second bath .

 

The clearing time should be checked often if that approach is used,

however, Kodak recommends 5-10 minute fixation with non-rapid fixers

and most films.

 

Since there is _no_ danger in longer fixing times, incorporating a

five minute minimum fix in each fixer bath into a

"normal" development procedure may avoid problems and

provide some security.

 

Agitation should be constant to remove fixer from the surface

of the film to facilitate diffusion, however, increased agitation

never can replace adequate fixing time or counteract the cumulative

effects of re-using fixer .

 

With rapid fixers, there is little "danger" of bleaching

film with 5-10 minute fixation. Also, if standard procedures are

used, any minimal bleaching would never be noticed, since it would be

incorporated into tests for contrast and development time.

 

With T-Max films, Kodak recommends longer times. For instance, they

suggest that it is "safe" to check clearing at five minutes

with standard fixers or three minutes with rapid fixers, and that

total fixing time should be twice the clearing time. (Kodak's

"advice" on T-Max varies from simplistic on 35 mm film

boxes, to warnings in detailed technical literature, not only on

times, but also on fixer replenishment rates for processors.)

 

 

<b>T-Max Films:</b>

 

With some films, such as Kodak's T-Max series, fixer capacity

is reduced to one-half of what one normally expect, and fixing times

are extended to twice the usual time, since silver iodide present in

the "high tech" emulsions is resistant to fixation, and

exceedingly insoluble.

 

In Kodak publication F-32 on T-Max films, Kodak indicates that a

magenta stain may be left in the emulsion with inadequate fixing, and

recommends further fixing with fresh fixer to remedy the problem. The

magenta sensitizing dye is adsorbed to the silver halide (EKC

statement - not speculation) and when the halide is fully dissolved,

the dye is removed.

 

In some instances, the dye can be removed by treatment with hypo-

clear, which usually contains sulfite or high salt concentrations

which can act as weak fixers in addition to displacing hypo, or with

prolonged water washes.

 

The "stain" problem isn't whether it will interfere with

variable contrast paper filtration or not, but its indication that

the film isn't fixed properly.

 

<b>Papers:</b>

 

For paper fixation, do not use fixer which has been used for film. It

is difficult to track capacity accurately (see table above... silver

capacity differs for film and paper), fixer dilutions vary between

paper and film fixers, and the "sudden" accumulation of

iodide after developing films may greatly prolong paper fixation or

leave insoluble silver iodide behind.

 

The clearing time for papers may be determined experimentally or by

manufacturer recommendation (for Ilford, see below). Fixing times for

most fiber papers is on the order of five minutes for each bath ,

with an intervening water rinse and storage in water. To save time,

prints can be fixed in the first fixer bath, rinsed and held in

water, then fixed in the second fixer bath at the end of a session.

Long contact with fixer can cause problems if fixer enters the

paper fibers (not between them). Papers and fixers vary, and it is

best to use at least the minimum time recommended by the paper

manufacturer.

 

Kodak recommends 10 min for fiber base and 2 min for RC in one

bath , or half that time for each of fixer two baths. The RC time

is optimistic, though five minutes per fixer bath is reasonable for

fiber papers. Prolonged contact with rapid fixers will slowly bleach

an image or cause uneven bleaching if prints remain in rapid fix

without agitation for prolonged times (hours).

 

In any case, paper and film should be promptly removed from the

second fixer , rinsed, and placed in a water fixer bath until

treated with a hypo clearing solution to displace free thiosulfate.

 

 

<b>Rapid fixer: </b>

 

Rapid fix has the advantage of a shorter contact time, and that may

minimize the penetration or degradation of fixer in the paper's

fibers.

 

Also, the useful capacity of rapid fixers is fairly high... 10-15 g/l

silver vs. 6g/l for films or 2 g/l for papers using regular fixers

(James; Haist table above for fixer bath 1 of a fixer two fixer

bath sequence).

 

However, there is little data to extrapolate those numbers into

increased capacity _without risk_ of problems. In that regard,

Kodak's recommendation for capacity of rapid fix and other fixers is

nearly the same (100-120 sheets or rolls), which is optimistic for

one fixer bath commercial processing. The only advantage of rapid

fix with film is decreased processing time and perhaps, decreased

rinse time.

 

 

<b>Hardeners: </b>

 

For film, a hardening fixer is often preferred to minimize any

emulsion damage in handling and to avoid reticulation. Very alkaline

developers can remove the manufacturer's hardeners. If the emulsion

is loaded with salts such as fixer , and placed in plain water, the

emulsion can swell markedly due to water uptake in the emulsion due

to osmotic pressure. If the water is warm, the emulsion may ripple on

the surface, giving the alligator pattern associated with

reticulation.

 

<b><i>Non-hardening fixers are often preferred for development of the

stain with pyro developers.</i></b>

 

For paper, rapid fix without hardener is often preferred, and gives

better results with toning. Paper curl seems to be minimized and

there is less danger of "breaking" the emulsion when prints

are flattened or mounted. Also, the avoidance of alum may reduce

silver complexes bound in the emulsion which can speed wash times.

 

If one wishes to remove hardener for toning, the following treatments

may be used: household ammonia diluted 1:10 (0.3%) for 2 min with 45

min wash or 5 min in 2% solution of Kodalk or sodium carbonate, then

wash.

 

An exception to the rapid fix recomendation is Agfa Portriga paper

which has a soft emulsion. If it is sepia toned (basic toner removes

hardeners), emulsion damage may occur if the paper is heat dried.

Therefore it should be hardened after toning. If fibers from a canvas

mat drier or blotters stick to the emulsion, you may have that

problem even with other papers. Kodak makes a separate hardener,

however, I find the hardener offered by Sprint to be effective and

economical. I also use it with their rapid fixer .

 

 

<b>Common Fixer Tests: </b>

 

Tests for fixer exhaustion which rely on precipitation of silver

iodide aren't sensitive enough to determine whether a fixer is in the

"archival" range or "commercial" range, and in

some cases, whether the fixer is near exhaustion. Relying on that

type of test with one-fixer bath fixation invites future disaster.

 

Likewise, tests of wash water for fixer can't detect insoluble

complexes of fixer in the paper or unfixed silver halide in the

emulsion. Sulfide or selenium toner tests for silver in paper don't

measure the insoluble complex (I) or degradation complexes, nor does

silver nitrate react with those complexes. Some tests may be better

than none and any warnings should be heeded, but in this instance,

they may give a false sense of security if the results are false

negatives.

 

Follow the tables given by Haist (above), and reduce capacities by

1/2 for TMax and other high tech emulsions.

 

 

<b>Hypo-clear and Eliminator: </b>

 

Usually, the removal of fixer and its complexes from film is fairly

straightforward. With or without hypo-clear, the hypo and complexes

diffuse out of the emulsion with washing, and aren't tightly bound.

The potassium alum used as a hardener may complex small amounts of

hypo and silver complexes, but that doesn't seem to occur with chrome

alum. However, chrome alum isn't used in commercial products, and

probably should be avoided for environmental reasons and staining

problems.

 

With papers, additional problems can arise due to the nature of the

support. Some of the hypo and complexes are adsorbed to the baryta

layer, fixer always penetrates the interstices between fibers of

fiber-base papers, and with prolonged fixing (over 15-30 minutes),

hypo and complexes can enter the fiber "cells", from which

it is very difficult to remove. However, this does not occur with

reasonable fixing times of 5 to 10 minutes.

 

The hypoclearing properties of saline solutions was discovered by Dr.

Bannow in 1889, but he used a 10% sodium chloride solution (100,000

ppm) with rinses with moderate success. In 1903, Dr. Bayssellanee

found that sea water was more effective, and used 30,000 ppm sea salt

with 1 hour soaks followed by washes to remove salt (so much for the

"US Navy discovery" myth).

 

Although it was noted that film and paper washed in sea water (3%

salts of which 2.6% is sodium chloride) lost fixer much more rapidly

than washing in tap water (65% faster for film; 80-90% faster for

paper), using table salt or sea salt as a clearing agent isn't a good

idea. Removal of chloride was required, since chloride resulted in

faster degradation of any residual hypo in the emulsion (note: the

seawater use was for rapid processing and conservation of fresh

water, not archival stability).

 

Subsequently other hypo-clearing agents were examined, and polyvalent

anions were found to be most effective in displacing silver. Of the

group, 2% sodium sulfite buffered to pH 7.0 was found to be most

effective. EDTA or other chelating agents may be included to remove

calcium sulfite which can precipitate in/on emulsions.

 

Although some suppliers indicate that a short soak in hypo-clear (1

min) after fixing followed by a short wash time is adequate, rinsing

films and papers before a 10 minute hypoclearing agent treatment

works better, and prolongs hypo-clear life.

 

<b>Hypo-Eliminators </b>

 

Hypo-eliminators rely on the use of an oxidant such as peroxide to

rapidly oxidize any residual hypo complexes in the film, preventing

the reaction with image silver which would occur if they were

permitted to degrade. Kodak HE-1 is a dilute mixture of peroxide and

ammonia made up when used (never kept in an enclosed container) which

oxidizes such complexes. However, it has been noted that oxidation is

incomplete unless bromide is added to speed the reactions.

 

In the "Craft of Photography" Vestal mentions that some

studies indicated that HE-1 treatment wasn't as "archival"

as supposed, and that a small amount of thiosulfate might stabilize

the image. The point was clarified at a subsequent conference

reported by Vestal. The topic is considered below (RC papers and

stability).

 

The current concensus seems to indicate that hypo-eliminators should

not be used unless the image is subsequently toned with selenium or

sulfur (sepia), or treated with Agfa's Sistan (thiocyanate).

 

 

<b>The Ilford Story: </b>

 

Coinciding with the introduction of Galerie paper, Ilford decided to

introduce a quick 20 minute archival processing procedure. After

development and stop, paper was to be fixed for 30 seconds in film

strength rapid fixer , followed by a five minute wash, 10 minute soak

in a wash aid, and another 5 minute wash.

 

Later, the recommended fixing time was extended to 1 minute with

little fanfare. If the wash aid isn't used, Ilford recommends a wash

time of at least one hour. The precautions mentioned include good

agitation, and use of fixer which hasn't approached its capacity. The

"theory" is that silver removal from the emulsion is faster

than accumulation in paper interstices, so supposedly little

accumulation occurs.

 

<b>There are some problems. </b>

 

The procedure does _not_ work with Kodak papers and others which

require longer fixing times. (Elite is a prime example.)

 

Also, the retention of complex I in the paper isn't addressed or

tested for, and complete non-image silver removal isn't checked.

 

Ilford recommends one fixer bath rapid fixation. A capacity of 40

sheets of 8x10 paper per qt (160 per gal) is suggested when a wash

aid is used with a single fixing fixer bath or when a fixer two

fixer bath system is used (which negates the short fixing time

rationale). However, the capacity is reduced to 10 sheets per qt (40

per gal) using a regular wash and single fixer bath fix.

 

That disparity in capacities suggests that Ilford is relying on the

wash aid to extend so-called fixer capacity when a single fixer

bath is used. The implication is that for the 30 sheet difference

between use and non-use of wash aid, significant insoluble complexes

are carried over (see the Haist table). Note that Ilford's capacities

for single fixer bath fixing are greater than Haist's

recommendation for commercial processing (Ilford uses 2 g/l with wash

aid or 0.5 g/l without). Their rapid fix might have a slightly

greater capacity, but it is unlikely that silver levels are as low as

Haist's _archival_ standard when silver levels higher than Haist's

limit for commercial processing are tolerated.

 

In the current Ilford tech sheet on Galerie, they mention that the

archival treatment with a 20 min wash results in 1/4 the level of

hypo in the paper as a 5-10 minute fix with "normal"

washing. Note that a wash aid wasn't used with the paper fixed 5 to

10 minutes in the "comparison". Remember, wash aids can

increase rate of fixer removal by 80-90% with papers. The comparison

really isn't valid, and it appears that Ilford's only standard for

archival processing is residual reactive (free) hypo levels, and not

the target of absence of insoluble monoargentothiosulfate and silver

halide.

 

<b>Toning </b>

 

I don't intend to cover this in any detail, other than to say that

selenium or sepia toning is required to ensure image permance,

especially if prints are displayed. Gelatin always retains some water

which can dissolve atomospheric oxidizing gases such as ozone and

nitrous oxides, which can bleach the image and permit silver

migration.

 

Toning in selenium (1:3 for color chage to 1:20 for permance with

minimal tone effect), or sepia prevents the problem. Also, it is

claimed that treatment with Agfa's Sistan protects the image, though

I can't find data to support their contention.

 

There are a number of arcane approaches to selenium toning. If Rapid

Selenium Toner is exposed to hypo in an acidic environment (acid

fixer ), the selenite will be reduced to colloidal or metallic

selenium, and a red stain will result. To avoid that problem, rinse

the paper after fixing, and dilute the Rapid Selenium Toner in a

solution of 2% Kodalk (20 g/l) rather than water or hypoclearing

agent. The dilute toner may be stored in a glass container until

exhausted through use.

 

 

<b>Water Spots </b>

 

Water spots are caused by high salt or particulate concentrations in

wash water, which dry onto/in the emulsion. If you have problems with

water spots, then soak the negatives or RC prints in the following

solution for a few minutes before hanging to dry (don't use a

squeegee - water will run off):

 

1 gal distilled water

10 ml Photoflo

100 ml 70% isopropanol (rubbing alcohol from a pharmacy - be sure

that it doesn't contain anything else)

 

The solution can be reused if it's filtered before returning it to

the storage container.</pre>

 

 

Thanks, Dan. Interesting stuff.

I really do believe rapid fixer 3-5 minutes, with hardener, is all that need be done.

Thanks for that, Dan. It's a very comprehensive explanantion of the chemistry. Very informative.

I know Ilford reccommends a two stop bath for archival. I lean towards less use of the same fix, maybe, twice or so as opposed to two step fixing just to simplify things.

Chris,

 

You mean two stage fixing, not two stage stop bath...

 

Hans,

 

That's the whole point of the article: You have to **assure** that the fixer removed the monoargentomonothiosulate (one silver cation and one hypo anion): Two stage fixing **assures** the halide and monoargentomonothiosulate removal.

 

The key point is that "after a few uses of fresh fixer, the less soluble complex (I) and silver halide are left in the paper or film at low, but destructive levels, although the film appears to clear."

 

Cheers!

Dan

Dan,

 

It was Bob who mentioned two stop baths. Notwithstanding, having read that article yet again I shall adopt two-stage fixing for all future work.

Ctein, in his book <i>Post Exposure</i>, found that Sistan does work as well as toning for image protection on RC paper, at least in the short term (a few years under bright light). See page 160.

How would two-step fixing apply to single use chemistry and processing in a Jobo? Just put another dose of fixer in the tank after the first fixer bath? That would bring the total steps to nine with three done outside the machine.

Also, taco boy mentioned something about the 'clearing' of film. Is this when the film is no longer light-sensitive?

Noelle, I just saw your two posts here.

 

If you're using chemistry in a single shot manner in your Jobo, what you do is make up double the volume of fixer, and save the second fixer liquid to reuse for the next batch's first fixer bath.

 

The whole idea is that 98% of the fixing is done in the first fixer bath; but that last couple percent of fixing can only be accomplished by using fresh fixer.

 

Since C-41 fixer is $32.50 for 25 gallons (5 gallon cubetainer); and since it works for everything, there's No Excuse for underfixed film!

Concerning the parts here about fixation and one bath vs. two baths: It all depends... I think one bath can work just as well for archival purposes under certain conditions. Two bath works economically only if you reach capacity in the first bath well before the tray life expires. I did some math to prove this point. If anyone is interested we can go over the math together to see if it makes sense.

interestin article.

 

 

from the tmy-400 data sheet concerning fixing and that slight tint.....

 

 

FINAL STEPS

Rinse at 65 to 75°F (18 to 24°C) with agitation in KODAK

Indicator Stop Bath or running water for 30 seconds.

Fix at 65 to 75°F (18 to 24°C) for 3 to 5 minutes with

vigorous agitation in KODAK Rapid Fixer. Be sure to agitate

the film frequently during fixing.

Note: To keep fixing times as short as possible, we strongly

recommend using KODAK Rapid Fixer. If you use another

fixer, such as KODAK Fixer or KODAFIX Solution, fix for 5

to 10 minutes or twice the time it takes for the film to clear.

You can check the film for clearing after 3 minutes in

KODAK Rapid Fixer or 5 minutes in KODAK Fixer or

KODAFIX Solution.

 

 

Important

Your fixer will be exhausted more rapidly with this film

than with other films. If your negatives show a magenta

(pink) stain after fixing, your fixer may be near exhaustion,

or you may not have used a long enough time. If the stain

is slight, it will not affect image stability, negative contrast,

or printing times. You can remove a slight pink stain with

KODAK Hypo Clearing Agent. However, if the stain is

pronounced and irregular over the film surface, refix the

film in fresh fixer.

Wash for 20 to 30 minutes in running water at 65 to

75°F (18 to 24°C) with a flow rate that provides at least

one complete change of water in 5 minutes. You can wash

long rolls on the processing reel. To save time and

conserve water, use KODAK PROFESSIONAL Hypo

Clearing Agent.

Dry film in a dust-free place. To minimize drying marks,

treat the film with KODAK PHOTO-FLO Solution after

washing, or wipe the surface carefully with a photo

The traditional purple is Indicator stop bath, with an acid-base indicator that is yellow in acid, and purple when not.

 

It seems that the T-Max films have a lot of sensitization dye (to make them red and green sensitive) which will color the developer and fixer.

I don't know that it is a good way to judge fixer capacity, though. You are not supposed to worry about reusing chemistry with dye.

 

As well as I know it, besides the iodide, T-Max grains dissolve only from the edges, another reason for slow fixing. And then you fix long enough to get the dye out, too.

ive used alot of film in the past 50 years n gotta say, the new t-grain films just blow me away. they are so controlable with beautiful tones n relatively no grain.

 

i just hate the print papers today. the greatest papers are gone for good. i put the same print on both new and old papers... those old agfas just put m to shame.

I have a package of Hypo Clearing Agent that I never mixed up, as I have been using

rapid fixer, which washes fast enough without it.

 

Well, for fiber based paper, there might still be reason to use HCA, but I haven't

done much of that lately. Film and RC paper wash fast enough.

Wha? Huh! Where am I?

Sorry, I fell asleep at the 43rd paragraph 16 years ago and woke up in 2020.

 

Interesting stuff.

Okay, one thing I've never understood with the two bath process: Why discard both fixer baths after five cycles (assuming they are NOT left exposed for a week)? Each cycle adds a fresh batch for bath #2. No matter how many cycles, you're always adding a fresh bath.

Okay, one thing I've never understood with the two bath process: Why discard both fixer baths after five cycles (assuming they are NOT left exposed for a week)?

 

Hi, that's a good question, and I do not think there is any good reason, on a fundamental basis, to discard after five cycles.

 

I suspect that some customers may have had an oddball problem show up, for some obscure reason, and the manufacturer decided that the easiest way to head off such problems would be to recommend a periodic dumping.

 

Offhand, I can think of a couple possible problems that a hobbyist might have. One would be a gradual buildup of sludge in the bottom of the tank/tray. If I were the manufacturer, I think I might be inclined to just tell the customer to dump (and clean) periodically, as opposed to step-by-step instructions on how to decant off the clear fixer, save it, dump the bad, clean trays, and replace the saved fixer into the proper trays.

 

I spent a lot of years in the photo lab operations of a large chain outfit, and we never just dumped processing tank chemicals; I think this is a practical demonstration that there is no fundamental need to. As a note, machine processing equipment generally has filtered circulation systems built in, so the sludge issue doesn't happen on a regular basis.

As a note, none of this two-stage fixing stuff is new. The article being quoted was written in 1988, over 20 years ago, and the author used references that were around 20 years old then. So 40 plus years for those references.

 

Back then the fundamental reason for two-stage fixing was probably to have "clean" fixing in the final tank while keeping the fixer costs under control. In more modern times, from perhaps the 1980s, the more significant issue has probably been related to effluent control. Specifically with respect to silver getting into the wash water.

 

There are some pretty stringent silver requirements in many municipalities in the US, and simply taking film out of a moderately used fixer and putting it into wash water can often cause that wash water to exceed the limitations per one's sewering permit. One obvious way to deal with this is multi-stage fixer systems, plus increasing the replenishment rate.

I figured the reason to empty the fixer trays (or tanks) might be to clean them, though that is never mentioned in the references. In my darkroom I always returned the fixer to storage jugs and cleaned the trays. I discarded the fixer in the first tray before it reached exhaustion. I never could see the logic in discarding everything after five cycles. But it's a moot point now. I use ink. But I miss the wet darkroom. I've worked in various darkrooms for around 40 years, starting with a home hobby darkroom as a teen.

I figured the reason to empty the fixer trays (or tanks) might be to clean them, though that is never mentioned in the references.

 

Yep, it's strictly a guess on my part.

 

I kinda suspect that the origin of that rec, at least from Kodak, may be lost to history.

Wha? Huh! Where am I?

Sorry, I fell asleep at the 43rd paragraph 16 years ago and woke up in 2020.

 

Moderator Note:

 

This thread was revived by two Spam attacks.

Those spam posts have been removed and those two User's Accounts have been terminated.

(innocent) Responses to that spamming, by bona fide Members have also been removed.

 

William

Interesting points. I follow my old time tested rules for fixing, I have been using wet darkrooms for black and white since 1973. My current darkroom established in 1999.

Film - make up a litre of film fixer with hardener at a time (Ilford Hypam raid fixer 1:3 dilution plus Kodak hardener). I reuse this fixer until emulsion clearing times reach 5 minutes. The fix time for film is double the clearing time but up to 3X clearing time is okay especially for Tmax emulsions (I do not like more than 10 minutes of fixing times though). I have a chart on my bottle with about 20-25 squares. A litre of film fixer is often good for about 20 rolls in reuse.

Paper - RC papers I make fixer with Hypam 1:7 dilution and NO hardener. I use one tray for RC. I use the same paper fixer usually for a couple of sessions, checking the quality with Edwal Hypo Chek

Fibrebase papers, simliar to RC but the second fixer tray is usually employed. The first tray of print fixer exhausts first.

I always use a hypo clearing agent in all cases even with RC paper, after a short water rinse. Wash tray has a Kodak tray siphon and I have a plexiglas Kindermann print washer for fibrebase print washing.

My used fixer is saved in gallon jugs for environmental collection.