From: Liam Lawless (lawless@ic24.net)
Date: 06/18/01-04:23:29 PM Z
Andre,
Thought I'd better say something as I feel responsible for your plight, but
really can't think of anything much! From what you say, it appears to be a
silver problem: the amount of silver I specified in the article should give
near optimal results, and adding more should not make a significant
differenxce to the image quality. The fact that it did suggests that your
saturated silver solution is deficient in some way. With too little silver
for the amount of salt employed (or an insufficient excess of Ag), printing
is very slow and D-max too low for a satisfactory print.
By omitting the sod. citrate and substituting extra sod. chloride, you have
upset the balance of the ingredients, but not by very much, and your change
should, in fact, result in a greater silver excess than provided by the
published formula. This is therefore not the cause of the trouble. Sounds
like your gelatin's OK too; I haven't heard of heating it in a microwave and
am not sure it's a good idea, but if it's worked for you before...
Afraid you'll have to investigate your solutions, but humidity is another
factor that could be playing a part. If you're getting the paper too dry by
means of a hair drier, or if you're working in the desert, this could also
be affecting sensitivity and density. I wouldn't have thought to the extent
that you describe, but maybe something else for you to think about.
Liam
-----Original Message-----
From: Andre Fuhrmann [mailto:Andre.Fuhrmann@uni-konstanz.de]
Sent: 18 June 2001 09:43
To: alt-photo-process-l@sask.usask.ca
Subject: POP a la Liam
Over the weekend I put in a POP-printing session and ran across a
problem as follows.
1st SETUP:
(A) Salty gelatine according to Liam Lawless's recipe in PF. [But
instead of salt + ammonium citrate I used just 5g plain salt per
200ml gelatine emulsion. This worked perfectly last time round.] The
emulsion was about half a year old, thymol added and stored in the
fridge -- smelled alright. Gently heated in a microwave to about 40
C.
(B) Silver nitrate, saturated solution (about =< 15%).
Paper: Arche Aquarelle.
Coated twice with glas rod; dried 30 minutes; exposed to UV: very
little happened (just a purple hue )-:
Thought the gelatine might had gone bad (but how??). So ...
2nd SETUP:
(A) I prepared a new batch of gelatine. Heated it gently the next
day in a water bath and added
(B) as before
Now I first tested (A+B) by dropping a bit on a piece of paper and
exposed it to the sun (still wet): it darkened within a matter of
seconds. Next: single coating; drying 1 hour; exposure to UV: same
effect as the day before )-:
3rd SETUP
I didn't want to throw away all the coated paper. So I put a single
layer of silver nitrate (about 6%) on top. Drying and exposure as
before: worked perfectly (-:
Of course, the 3rd setup is sort of midway between traditional salt
printing and POP. But I wanted the latter. Any suggestions as to
what might have gone wrong?
André
This archive was generated by hypermail 2b30 : 07/12/01-11:41:54 AM Z CST