Topic: Contact Printing on Film?

[Dan D.]

OK, here's the situation.  I want to make a solarized negative, which has a bunch of subsequent steps.  The first step, however, is to contact print a negative onto another piece of film.  (This would also be a cool way to make B&W slides, now that I think about it.)  The problem is that I need to figure out how long to expose the film with my enlarger head.  My original thought was to stop down to f/22 on the enlarging lens, raise it to maximum height, and take a gray card reading.  However, I now realize that would give me any number of different exposure times based on aperture.  Since there's no camera lens, there's no aperture.  So, how long do I expose the film?  (Note: I bought some Ilford Pan F to test this process.)

[Francois]

Only thing I can say is the exposures will probably be quite short...
Doing a test strip might be the only way to really know...

But come to think of it, if you take an incident reading of the light going through the negative, that should be the correct time...

You know the ISO if the film, you have an exposure meter (your camera or handheld), gray card... you have everything you need.

Besides, Sabbatier effect is quite variable since there are 2 exposures.

[Heather]

I've never gone that route... I've enlarged from film (small, 35mm) projected onto ortho litho film (APHS from Freestyle Photo), then contact printed the resulting positive to get a negative. Ortholitho film is really slow, it's basically like B&W paper speeds and developed in B&W paper developer.

I have projected (35mm again) onto panchromatic 4x5 film. It was fomapan 100 and the times are surprisingly in the range of 1second steps even with the lens opened up a bit. Just do test strips like you would in normal B&W printing.

You may have to do some experiments and lots of test strips and realise you have to work in total darkness (no safelights) when working with panchromatic film like PanF.

[Dan D.]

Francois,
I would think that I have everything I need, but my exposure meter gives me a reading in the form of a shutter speed/aperture combo.  So let's say I read 1/125 of a second at f/11, which I think is 1/60 of a second at f/16.  Neither says how long I should expose the contact print for, since there's no aperture setting for a contact print other than the enlarger lens, which just controls how much light there is to begin with...

Heather,
Wow, I've never heard of Ortho Litho film.  It looks like just what I'd need, since I'm in the darkroom and using paper chemicals already.  I'll try the Pan F for now, but I'll try this new film once I can make another film order from Freestyle.

[Francois]

Francois,
I would think that I have everything I need, but my exposure meter gives me a reading in the form of a shutter speed/aperture combo.  So let's say I read 1/125 of a second at f/11, which I think is 1/60 of a second at f/16.  Neither says how long I should expose the contact print for, since there's no aperture setting for a contact print other than the enlarger lens, which just controls how much light there is to begin with...

One way you could do is is to remove the camera lens and project the enlarger image directly into it. That would take the camera lens out of the equation. If your camera has a top mounted display, it won't be a problem to read the recommended shutter speed. It would also take into account the film ISO and the enlarger lens' aperture.

As for the shutter speed, just use a calculator. 1/125 sec = 0.008 sec... simple

If times are too short for your enlarger timer, you could consider either adding neutral filters or using black cardboard to make a "replacement head" for your enlarger and simply use an electronic flash to make the exposure.

[Dan D.]

Stupid me - that would be a great way to do it.  Here I was thinking I would use my hand-held meter to do it.  Though I may want to look into this further - I think there may be a way to convert the hand-held meter reading into some sort of concrete value with units and whatnot.  Lumens, is it, or lux?

Anyway, I'll try the camera-metering thing.  And perhaps a flash unit might not be a bad idea, depending on how much light it produces...