First of all...

Look at this link!

For those who seriously want to explore archival aspects, you cannot do better than hit this link, which takes you to the Wilhelm Imaging Research site. A new offering here is the entire 758 page book 'The Permanence and Care of Color Photographs: Traditional and Digital Color Prints, Color Negatives, Slides, and Motion Pictures' which has been placed here as a free downloadable set of PDF's. (It's 80 Mb, though, be warned!) The printed volume previously cost about £50.00, and is an immense resource for permanence in all traditional photographic media.

http://www.wilhelm-research.com/book_toc.html

What archival processing is
Archival processing of fibre-base paper is simply a matter of fixing, washing and toning, to certain standards, to ensure the longevity of the photographic material.

Controlled fixing
Fixing takes place in a series of chemical changes;

The first fixation product is almost insoluble in water, and is then converted into more soluble products, but this second conversion ONLY takes place if there is excess fixing salt available. As well as the necessary availability of free thiosulphate, silver is converted into silver-thiosulphate complexes, and at a certain level these will bond onto the paper fibre structure. One approach is to process only a relatively small number of prints through a fixing bath, and discard it when it has reached a specified silver level, a safe level being 0.5 grams/litre. This can be checked with silver estimating strips. Ilford's 'Galerie Sequence' is a refinement of this approach (next page). An alternative method is to use 2 bath fixing. The first bath performs most of the work, taking the print to stage 1, and the second fresh bath ensures that all the silver salts are rendered soluble. When the silver level of the first bath reaches a safety threshold (2 grams silver per litre) it should be discarded, replaced with the second, and a new second bath used.

Hypo Clearing Agent
This is a bath used after fixing to assist in washing out fixer and its products by ion-exchange, and can help achieve a lower thiosulphate level than washing on its own can manage. It also considerably improves washing efficiency when using cold water. Hypo clearing is highly recommended, being cheap, quick and effective. It is not to be confused with Hypo-Elimination which is a different chemical treatment to break down the last vestigial traces of thiosulphate, and in the light of recent research (arguably) not desirable or necessary.

Suggested Sequence

1. Development
To completion. Manufacturers generally recommend 1.5 minutes, but it is worth doing your own tests to ensure you are reaching the maximum black of the paper under your particular conditions. Agitation should be thorough and continuous.

2. Stopbath
Sufficiently long to de-activate developer in the paper core, 10 seconds should be sufficient. Agitate continuously.

3. Fixing
2-bath fixing in a non-hardening fixer, 5 minutes in each bath for sodium thiosulphate fixers at normal paper strength, 2 minutes in each bath for ammonium thiosulphate fixers at normal strength. Rotate the baths, discarding the first when the silver level reaches 2.0 grams/litre.

4. Wash
15 minutes - basic wash to reduce hypo content to a low level to avoid staining in toning.

5. Selenium Toning
As a starting dilution try 1+15 with Kodak Rapid Selenium Toner. Other toners may require different dilutions for the same effect. Agitate continuously, and use gloves and/or tongs, as it is highly toxic, and absorbed through skin! Good ventilation is also desirable, and performing this step in the open air is not a bad idea, as the changes can be seen most clearly in daylight. An untoned print alongside the toning bath, in a dish of water is also useful for reference. Keep looking away from the toning print to stop your eyes adapting to the colour change.

6. Wash
5 minutes, a brief wash to prolong the life of the Hypo Clear bath. Dry using a method as recommended on previous page.

7. Hypo Clear Bath
Follow the manufacturers recommended dilution, and agitate continuously. Some sequences place the hypo clear stage prior to selenium toning, or mix the Hypo Clear bath with the toner. There is actually a high thiosulphate content in Kodak Selenium Toner, and the clearing stage therefore seems best applied later in the steps, after toning.

8. Full wash
60 minutes minimum in an efficient print washer should reach a satisfactorily low level, so long as the water temperature is not too low- below 10°C a rule of thumb is to double the wash time. A basic check on washing efficiency which will detect serious problems is using HT2 solution in conjunction with the Kodak Hypo Estimator.

Extra Care At The Drying Stage
'Air-drying' ideally, since nothing comes into contact with the wet print which can contaminate it, eg the canvas aprons on heated dryers. Several methods:

1. Fibreglass Mesh Using plastic-coated fibreglass mesh to construct screens on which the print is laid, usually face down. Free circulation of air will give a relatively flat print. We have several options in mesh, either by the yard, so that you can construct your own system, or in ready made units from Zone VI.

2. Back-to-Back Method Drying 2 prints back to back, pegged on lines with plastic clothes pegs, with further pegs at the lower corners. Line the prints up back to back while still in the washwater, then holding them together draw them out. They will stick firmly together, and are simple to peg up on the line. With large prints, put further pegs at suitable intervals around the edges. The inherent curl of each print will tend to cancel out, and the prints should need only minimal flattening.

3. Blotters Alternatively, the use of blotters, going through several stages, fresh dry blotters at each stage, from damp to semi-dry, to completely dry. To do this properly does need quite a lot of blotters, but the 3 stages are necessary, as if the print is too damp it will dry into the surface of the blotter.
Further flattening after your selected drying method can be carried out under weights, or if you have access to a dry mounting press, by 30 seconds or so at a reasonably low heat, between 2 archival boards. Dry the cover boards by leaving in the press for a few minutes before use, to make sure they are not carrying too much moisture, which could mark the print surface.

This is a new way of looking at the requirements of archival processing, and the steps are modified from the above sequence. A highly concentrated rapid fixer is used (Ilford Hypam is recommended), followed by a short wash, a longer hypo clearing stage, and another short wash. Development and stopbath stages are as normal, after which these steps follow;
1. Fixing
Ilford Hypam is recommended, but an equivalent rapid fixer can be used. The extra strong concentration of 1+4 dilution is used, for 60 seconds, agitating constantly Thirty seconds was the original recommendation, but due to the difficulty of ensuring even coverage this has now been increased to the longer time.
2. Wash
5 minute wash. in running water
3. Hypo Clear
10 minutes in Ilford Galerie Washaid. Other hypo clearing agents can be substituted.
4. Wash
Final 5 minute wash in fresh running water- preferably do not re-use water from the first wash.

The idea is that by using rapid high strength fixer, the fixing time can be cut down to such a short time that little penetration of the paper base takes place, and the wash time can also be reduced. While the sequence works well, achieving hypo limits as low, or lower than the best conventional processing, it does require scrupulous attention to the fixing step. Unless this is timed accurately, using fresh fixer, there is not much point in going this route.
Also the number of people using this sequence that we know of could be counted on one hand- it is simply too demanding in its timing requirements. But the significant step is the controlled fixing time; if using the Galerie sequence, after a 30 second fixing time a residual level of 0.14 micrograms/sq cm remains in the paper after washing, while with a 60 second fixing time the residual thiosulphate figure is 0.16 mg/cm2. After 60 seconds the residual hypo content rises rapidly - with a 2 minute fix time it reaches around 0.60 mg/cm2. If the short and carefully timed fix step is used, you can please yourself on the timing of subsequent hypo clearing and washing stages, as long as they are of adequate length. The new 'Academy 2' washer from Nova is designed to help fit hypo clearing into a sequence. We recommend running some HT2 tests, though, before trusting to your departures from the Ilford guidelines.