Paper light sensitivity

[EKDobbs]

I'm making a ULF pinhole camera, but running into the issue of f/stops in the triple digits. The other issue is that I definitely do not have the money for LF film, much less ULF film. Therefore, I'm using B/W print paper, which as I understand has and effective ISO of 3 to 12, depending on who you talk to.

I'm wondering if there's anyway to get that sensitivity higher. I don't care how grainy/contrasty it gets, I'd just like to push the iso to at least 25. Maybe using really high concentration developer? Are there brands/types of paper that are particularly sensitive?

Any information is appreciated. Worse comes to worst, I just have to deal with sunny day exposures ranging in the minutes, or softer pictures.

 

[piu58]

- cold tone papers are more sensitive than warm tone papers
- Foma is more sensitive than Ilford
- You may use preflashing which additional gives a softer graduation. Paper is hard in comparision to film.

 

[Stan160]

I've not experimented with paper negatives much, but based on experience with enlargements, Kentmere VC Select paper requires much shorter exposures than Ilford.

Ian

 

[RalphLambrecht]

true.paper exposed to daylight has too much contrsast, but a light yello filtertakes care of that nicely.

 

[removed account4]

hi

some papers have an iso of 25-50 believe it or not ...
paper is funstuff ...
if you process it in exhausted print developer you can control the contrast more.
i process all my paper negatives in 2 baths. 1 is print developer, and one is a coffee based developer.
they come out great. the thing to also think about is that what looks good as a paper negative
might not look good as a film negative. paper negatives sometimes look "thin" whereas film negatives have some meat on them.

have fun !
john

 

[brianmquinn]

Another way to control the excessive contrast is to develop in film developer. What ever film developer you have on hand or dilute you regular paper developer. Also normally you develop a paper for a standard time and just expose another sheet if you need more or less exposure. With a slow working developer you have the option to pull a sheet early if it is overexposed since getting another pinhole shot is not that easy.

 

[Rick A]

A visit to this site may prove helpfull.

http://www.f295.org/Pinholeforum/forum/Blah.pl/Blah.pl?b-cc/

 

[Mainecoonmaniac]

I didn't know that

true.paper exposed to daylight has too much contrsast, but a light yello filtertakes care of that nicely.

Thanks Ralph! It's a wonderful tidbit of very useful information. I'll definitely use it.

 

[EKDobbs]

Alright. So I'll probably use foma paper, exhausted paper developer and/or caffenol, and shoot with a yellow filter. Hopefully the combination will push me to around effective ISO 50. A few stops can turn an evening out for a nightscape into three weeks of waiting.

 

[piu58]

> exhausted paper developer

I recommend film developer. It gives less contrasty paper negatives.

 

[removed account4]

Alright. So I'll probably use foma paper, exhausted paper developer and/or caffenol, and shoot with a yellow filter. Hopefully the combination will push me to around effective ISO 50. A few stops can turn an evening out for a nightscape into three weeks of waiting.

it is best to do a few tests before you do the real thing
if you can grab a 35mm camera or something smaller
so you can do some iso and developer combination tests.

at one point years ago i tested about 10-15 different papers
to figure out their iso values relative to film, and they varied wildly ...
expired paper can do wonders as a paper negative because the
basefog helps deal with the contrast ... you might not even need
out of the ordinary developers, just regular old paper developer..

you might want to check out the caffenol blog ( http://caffenol.blogspot.com/ )
for some easy recipes ( you just need a scale or some way to measure your ingredients )
if you use caffenol to process your prints ( and no print developer as a pre-bath )
it can take 2x or more the normal development time to get an image on your paper .
( instead of pulling the print at 2 mins, the image appears in 2 mins &c ) ...

good luck !
john