more-dense film, less print time ?

[removed account4]

i have a kind of strange thing that happened over the weekend
i shot a bunch of tmy and tmx sheets
all at the same speed, so the tmy is 2 stops more exposed ..
they were all processed the same, in the same tank, with the same chemicals. ( it is old tmy, not the new stuff )

i printed them out onto ilford rc paper and used the same chemistry.

the tmx was 50 seconds
and the more dense tmy took 2 seconds to expose.

i even moved the light source up about 6 inches,
or my exposure time would have been even shorter

(i'm using a 300watt bulb )

anyone have any suggestions as to what might be going on ?

it makes absolutely no sense ( to me ) that a more-dense negative
would would take so much less time to expose.

thanks in advance for your expert opinions!

john

 

[DanielStone]

what about film base fog? Older films have more fog, and some developers increase fog levels over other films.

-Dan

 

[Ian Grant]

It's a physical impossibility unless your lens wasn't stopping down properly or the TMY was so old taht it had drasically lost contrast & speed which can happen. There's over 4 stops enlarger exposure difference.

Ian

 

[JSebrof]

I remember reading some time ago that TMX has a layer that absorbs UV light that TMY doesn't have. The discussion was geared more towards alternative processing where uv is the principal light source, but Ctein mentions in his book Post-Exposure that uv light from the enlarger makes up a lot of the exposure in a print. I don't have the book in front of me at the moment, but I recall he ran an experiment where he placed a uv-filter in front of the light source after making a print and a lot more time had to be added to compensate. Perhaps what you experienced is somewhat related to this?

 

[removed account4]

daniel

i can't speak about the base-fog, the negatives are dense enough
that i have shine a lantern through them to see what is on them,
and the tmy is denser than the tmx.

ian
i too thought it was a physical impossibility.
i wasn't using an enlarger, just a 300 watt bulb in a reflector.

JS
i thought immediately about the UV layer, but i always thought it was in the tmy, not tmx, but am thinking that you might be right ...

=====
added 4 minutes later:

i just got off the phone with the good people at kodak professional ( again )
and learned that sheet tmx has always had the UV absorbing layer, and it has never been in sheet tmy.
it was added to tmx ( 35mm and 120 film in 2007 )

maybe this IS the answer ?

thanks again
john

 

[L Gebhardt]

The UV filter is in TMX and not in TMY (as you have confirmed with Kodak). That was my first thought, but I can't imagine a 300watt bulb giving a 50 second exposure time on Ilford RC paper. Something seems very odd. When you say "printed them out" you don't mean you are using the paper as printing out paper do you?

 

[removed account4]

hi larry

sorry i didn't see this until today
i (over) process my film so it is (really) dense ..
so dense that i have to put a flashlight behind it
to see what the image is of. when i said print them out ..
i am making contact prints of the film, but because the negatives
are "developed to completion" i use regular rc paper and use the same exposure
as azo paper ( even thought it is a different beast altogether )..

it's kind of fun
attached are 2 images, one of the first ones i did like this using fb paper,
processed in a dimly lit ( moonlight ) basement/washroom
in france at my inlaw's house .. straight caffenol c shuffled for 22 mins
and another one ... from the film i processed when i posted this thread in june 2010 ..
caffenol c + a splash of ansco 130, stand developed in a FR tank for 25mins

- john

 

[piu58]

When I make prints at first I determine the minimum time for maximum black. Therfore the blank film is used. Is is of less sense to take much lesser light, because you aren't able to get a deep black.
I cannot imagine that this time goes from 2 to 50 seconds. I recommend to make this test first.

 

[removed account4]

When I make prints at first I determine the minimum time for maximum black. Therfore the blank film is used. Is is of less sense to take much lesser light, because you aren't able to get a deep black.
I cannot imagine that this time goes from 2 to 50 seconds. I recommend to make this test first.

it turns out it is the UV inhibiting layer in tmx that causes
my extended exposure times. i didn't realize that the uv layer
increased non-uv light source developing times as well.

thanks for your methodology just the same, it is always good to have another
trick in the bag !

john