Black and White Film and Artificial Lights

[IanBarber]

When I was doing low key still life with the digital setup it was fairly easy because you could see the results on the screen. Now I have moved to 4x5 everything appears to be heading south on me.

I use the following lights

• Modelling lamp from a studio head (usually with a 10° grid)
• Incandescent light

I have noticed that the majority of my exposures look awful, under-exposed, mushy low values.

I use the manufacturers (Fomapan) reciprocity times for exposures longer than 1 second but I have noticed that their data sheet does mention these times are for daylight.

Does black and white film react differently to this type of lighting in any way ?

[Bruce Watson]

I have noticed that the majority of my exposures look awful, under-exposed, mushy low values.

I use the manufacturers (Fomapan) reciprocity times for exposures longer than 1 second but I have noticed that their data sheet does mention these times are for daylight.

Does black and white film react differently to this type of lighting in any way?

Why yes, it does. Panchromatic films are basically orthochromatic films with added sensitization dyes to extend sensitivity down into the longer wave lengths. So to expose a B&W film to light that is lacking in blue light can push it into reciprocity failure sooner than you'd think.

Compounding this, the older cubic-grain emulsions (and Fomapan is a very old emulsion) are more problematic about this than modern t-grain emulsions. You probably would find your problem greatly diminished if you were using TMX, Delta, or Acros.

That said, the old saw: expose for the shadows and develop for the highlights" still holds true. If your shadows exhibit "under-exposed, mushy low values" then give them more exposure.

[IanBarber]

Thanks Bruce

I can see this really been trial and error especially if reciprocity kicks in sooner than you would expect

[Leigh]

Film emulsions are most sensitive to blue light.
That's just the nature of the chemistry and technology.

Sensitivity can be extended down through green to red and even infrared by adding "sensitizers".

Comparing the spectrum of an incandescent light to the spectrum of daylight shows a dramatic difference.
With daylight, the intensity peak is at blue, with green being lower and red being much lower.
An incandescent source has an intensity peak at red, with green being lower and blue being much lower.



Depending on your meter, your readings may be quite a bit wrong when measuring incandescent.
Some experimentation is in order.

- Leigh

[IanBarber]

Depending on your meter, your readings may be quite a bit wrong when measuring incandescent.
Some experimentation is in order.

I use a Sekonic L758 Meter, usually taking incident light reading for this type of setup. So looking at those charts, with the blue been very low under incandescent and the fact that the light meter may be giving false readings, i feel a-lot of experimentation maybe required as you say

[Peter De Smidt]

I would do a bracketed series of shots of your scene, starting with your normal speed for outdoor use, moving on to a negative with 1 stop more exposure, and finishing with a negative with 2 stops more exposure. Develop normally and evaluate the negatives. You should be able to figure out the best EI for that film, developer, and lighting. When I tested HP5+ with tungsten lighting, my EI was only 100.

[IanBarber]

Just a thought although I maybe way off track, would adding a blue filter to the light source increase the amount of blue which is what the film like to receive

[John Olsen]

Does black and white film react differently to this type of lighting in any way ?

Normally you'd use a green #11 filter on the lens to get the tonal range of the image with tungsten light. This is consistent with the replies above concerning the redness of the hot lights. Of course, that costs two stops of exposure, pushing you further into reciprocity compensations. But you can get good images this way.

[Harold_4074]

Ian,

For educational purposes, you might play with your digital camera: white-balance for daylight, and make your picture with incandescents. I expect that you will get images that look extremely warm, whereas the same picture with the camera white-balanced for the incandescents will look "normal". The human vision system has a pretty robust mechanism for adapting color perception to differing light sources, so the film may be reacting to the colors in the still life in a way that is difficult to visualize.

Your incident metering is of course immune to the colors in the subject, so you might consider doing a few exposure tests with a gray card to find out what the basic reciprocity correction should be in the mid-tones, and then work on contrast adjustment from there.

In my own experience, I have found that pastel fabrics in pink, yellow and pale blue render in ways that are very difficult to predict (Caucasian skin, for example, on the negative just disappears against pale blue even though it is clearly separated visually). For reasons probably originating in dye technology, the darker earth tones seem to work well in both incandescent and strobe (nominally daylight-balanced) light. This is handy if, for example, you are photographing pomegranates (deep red and black) against natural burlap (medium tan) with leaves (yellow and green) and a flat black vase.

[IanG]

Check manufacturers data sheets B&W films have a different ISO for daylight and tngsten lighting. Some of this is no longer included on the most recent data sheets so look at ones from 15-20 years ago it's still the same.

Then add the filter factors if used, there's a guy in the UK with excellent misleading data (some for sale) about all this, he has a few websites & forums and never gets anything right

Ian