Standard Bostick and Sullivan chemicals, grade 5, half platinum, half
palladium, on Cranes Platinotype paper. Coated two sheets with some tape
running across them (to leave some "virgin" paper, see post below), in a
safelight only situation, let them dry in total darkness. Determined that
10 seconds of exposure without a neg gave me a very pale gray when
developed, so exposed half of the test paper (the half without the tape)
for 10 seconds.
I then cut all tests into three pieces and exposed them for 15 minutes, 30
minutes, and one hour with a coin covering part of the paper (to see if it
would leave a paler circle). Tested one set in my normal working light (I
simple leave the hallway lights on and my darkroom door open, F2-1/2 at 1
second at ASA 100 on an incident meter), and another in the hallway itself
(typical indoor lighting, F4-1/2 at 1 second at ASA 100 on an incident
meter, 7 feet from a 75 watt bulb).
Developer was Ammonium Citrate at 100 degrees. Clearing was three 5 minute
baths in EDTA (3 teaspoons per liter of water). In my normal working light
tests, I couldn't see the coin's "shadow" after developing on any of the
pre-exposed tests or the "unexposed with tape" tests (15, 30, 1 hour). So,
I do consider this a perfectly safe light level (YES!!!). In the hallway
itself, I couldn't see the coins "shadow" on any of the "unexposed with
tape" test, but did see it on the pre-exposed 1 hour test. So, if you are
working with normal rooms lights on, you may want to be careful (or test).
The problem with testing, is it always seems to show you something you
didn't expect. Someone in this thread (Jeff ?) said that developing the
paper with tape on it (to avoid getting chemicals on a section of the
paper) was not only a way to test for safelight fogging, but if you
developed a piece that hadn't been exposed to any light, it was a way to
test if your clearing was complete. Unexposed paper in my situation does
show a very slight "stain", compared to the "virgin" paper under the tape.
I tried doubling my clearing time (three 10 minute baths), without any
change. This "stain" didn't change from the unexposed test to the 1 hour
tests, so we aren't looking at safelight fogging here. Is this an
indication of a problem, or simply unavoidable "staining"??
P.S. If you try these tests, you may be amazed at how inconsistent your
light source is. I don't think it matters, but I couldn't get my 10 second
exposures grays to match at all.
tomf2468@pipeline.com
>Jeff wrote:
>
>>Before you all start commenting on how careful you all work. (And, I am
>>confident that we all are excellent technicians with alternative
>>processes.) You may wish to test if your ambient lighting is safe.
>>
>>Do the following for two situations 1) in your typical ambient light; 2)
>>with a safelight safe for working with typical B&W silver papers.
>>
>>Place some removable tape on paper normally used.
>>Coat as usual. (Be careful when drying not to let coating puddle near
>>edge of tape for this may influence results.)
>>Mark the edge of the tape with pencil dots.
>>Remove the tape.
>>Process through all processing steps as is typical.
>>
>>After dry, examine. Look carefully along the pencil dots for any change
>
>I disagree. This kind of test may give you negative results yet you may
>still have a fog problem. The effect of light is cumulative. Therefore fog
>problems will manifest themselves in the *highlight* and *light* areas of
>the print, well before they appear in *unexposed* areas of a print. The
>same goes for other photographic processes in general.
>
<SNIP>