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Re: Mix your own FO?

Nick, I would suggest that you look into making, not mixing, your own.  Jeffrey
has posted the process on his site.  I have tried the product that he made with
that process.  I works fine.  It like other processes is only as good as the
person running it.  I have followed a procedure outlined in Dick Stevens' book
on the kallitype.  The method involves the use of oxalic acid, something that
you probably already have around your studio. It also uses ferrous ammonium
sulfate, something that you most likely don't have around your studio and some
35% hydrogen Peroxide.  The first time I made it with these chemicals I bought
500g of ferrous ammonium sulfate, some where around $55.00.  The peroxide from
Bryant labs 500 ml, around $25.00 .  Both of those are much cheap at larger
quantities.  2.5 kg of ferrous ammonium sulfate was only $99.00 or 5 times as
much for less than twice the cost.  The oxalic acid is cheap enough, and if you
use it for your clearing bath, you should have plenty of it around.  This may
not be the best method, but it will give you good repeatable results.  I find
that it yields about 1.5 times the amount of ferrous ammonium sulfate used.  For
example: if you use 50 g ferrous, you would expect to yield 100 ml of ferric
oxalate.

It is also relatively quick.  There is no rehydration or mixing from powder,
because you end up with liquid ferric.  On the down side, it may contain unknown
compounds.  They may not be bad or present a problem with making excellent
prints.  I have been doing it this way since early in 1994.  B&S hasn't seen a
dollar for ferric since.  I would suggest that you try it.  The method that
Jeffrey has posted may be a bit more handling of messy by products than you want
to get into.  Either way you go, you'll see that making ferric your self can be
rewarding and it is much cheaper than buying powder.  You will also see that a
fix to "bad" ferric is at hand.

Have fun.  If you would like I'll send you a write up on how to make ferric with
Ferrous ammonium sulfate, and oxalic acid, and H2O2 - 35% .

EJ Neilsen

Nick Makris wrote:

> Hello again,
>
> I'm about to start another iteration of PT/PD prints and have to order some
> chemicals.  The question that arises is whether to mix your own Ferric
> Oxalate or to buy it premixed such as that from B&S.  I know what some (one)
> person would suggest - Jeffery says mix your own and learn from the
> experience.  What I need to know is what are the trade offs; example, able
> to mix smaller amounts than you can purchase otherwise; or, less expensive;
> or, what.  Is it worth the trouble and how much trouble is it, after you've
> gotton the process down??????
>
> Many thanks for everyone's help - it's a great group.
>
> Nick

--
Eric J. Neilsen
4101 Commerce Street, Suite #9
Dallas, TX 75226
214-827-8301
http://e.neilsen.home.att.net
http://www.ericneilsenphotography.com