Acid rapid fixer for fb papers?

I recently purchased a few bottles of MACO ecofix, but after delivery I read the fine print on the bottle (which was not visible on the product images I'd seen) which made me a bit confused, and no googling have given me a good answer.

The fine print:

For acid-free fixing of fiber base papers, we recommend the use of ROLLEI FIX NEUTRAL, #RXN

Click to expand...

What does this mean? I'd like to treat by fb prints to an archival standard (or as close as I can get), I use double fixing bath, a pre-rinse, HCA and then wash for 30-60 minutes. Will using an acid fixer make this harder?

The product I purchased: https://www.macodirect.de/en/chemis...eloping/fixer/1618/maco-ecofix-fixing-bath-1l

In a way, it doesn't mean anything. Some people prefer to use a non-acid fixer because it shortens wash times. But your method is traditional for acid fixer and is fine. (Well, if you are really concerned test for residual fixer to see if you need to use a longer wash time or can get away with a shorter one.) They specifically mention fiber base because FB paper is the only material where wash times really matter since they are already quite short with RC paper and with film.

Oscar,

The fixer you have will work just fine. It is a rather conventional "rapid" fixer based on ammonium thiosulfate. Use two-bath fixation and keep to the capacity and you should have well-processed prints. Make sure you use a wash aid like Kodak Hypo Clearing Agent or Ilford WashAid before washing. Wash for a minimum of 60 minutes in running water (or many changes of water).

If you're really interested in processing for optimal permanence, read up here on fixing and washing and learn how to test for residual hypo (Kodak HT-2 test) and residual silver (ST-1). Toning or using a stabilizer like Sistan is also a good idea.

Best,

Doremus