Black and White Film and Artificial Lights

[IanBarber]

I think best thing i ever did for my still life stuff is to by visual target scale that takes all the guess work away - you just stick it to your object, focus, measure compensation on ground glass and move on

Do you have any information where these can be obtained from

[chris_4622]

Try this:
http://www.salzgeber.at/disc/

[IanBarber]

Thanks, that looks interesting, I will try that

[IanG]

It's actually all quite simple. The OP is I think is using Foma film but has no idea of the true EI, that needs tests but for Daylight most use half the bos soeed and reduced development, the with tungsten light ut will bewill be less, Then there's reciprocity Foma films are supposedly bad, my tests and use show that's not qnyware bad as the manufatcturers nfigures, as long as you've tested and haniled the true EI ansd development time.

The other factor is the OP probably hasn't allowed for the bellows extension for close up work.

So we have three issues, no idea of the true film speed with tungsten light, no allowance or more importantly testing for reciprocity , all made worse by no allowance for bellows extension, a recipe for disaster

Ian

[Leigh]

So we have three issues, no idea of the true film speed with tungsten light, no allowance or more importantly testing for reciprocity , all made worse by no allowance for bellows extension, a recipe for disaster

While that's certainly true, I'll add a fourth issue.

Random tungsten lighting is a recipe for frosting on the disaster cake because the spectrum isn't predictable.

The illumination level varies with AC line voltage, and the spectrum varies as the intensity varies.
This creates problems with filtration and correlating light meter readings with true exposure.

- Leigh

[John Olsen]

While that's certainly true, I'll add a fourth issue.

Random tungsten lighting is a recipe for frosting on the disaster cake because the spectrum isn't predictable.

The illumination level varies with AC line voltage, and the spectrum varies as the intensity varies.

- Leigh

Yes, random lighting is unpredictable, but if you use real tungsten bulbs of 3200 degrees the spectrum is certain. Buy good stuff and it works well, or buy cheap crap and have problems. Really, you're making this much more mysterious than you need. Hot lights have been a reliable part of photography for a long time. I think there's some reinventing of the wheel going on here. Please go back and look at the classic photo manuals. Then notice out how cost-effective tungsten is compared to flash for still lifes and architectural work.

[Leigh]

Yes, random lighting is unpredictable, but if you use real tungsten bulbs of 3200 degrees the spectrum is certain.

Yes it is certain, but for perhaps a very short period of time.

Bulbs with color temperature ratings can have service lives as short as 4 hours, but typically 40 to 100.

Halogen bulbs last longer, but still not nearly as long as similar lamps used for general illumination.

Then notice out how cost-effective tungsten is compared to flash for still lifes and architectural work.

Tungsten for architecture?

You must have a huge lighting budget, and a very large generator mounted on a truck.

- Leigh

[IanBarber]

So we have three issues, no idea of the true film speed with tungsten light, no allowance or more importantly testing for reciprocity , all made worse by no allowance for bellows extension, a recipe for disaster

Ok so lets go back to the beginning and look at Personal EI.

I have read how people consider to be very useful and I fully appreciate the reasons for finding out this information about a particular film.

For someone like myself who does not use, own or have access to a darkroom and darkroom equipment and solely relies on scanning the negatives prior to digital printing, can anyone explain or at least point me in the right direction to how I can find out the EI of my films.

[IanG]

Foma films are in a league of their own, the published ISo and ndevelopment times seem way off to most people but once you've nailed the effective EI and development times they are excellent. I didn't use a darkroom when I did my own EI tests on Fomapan 100 & 200, rather than using sheet film I used 120, in the past I've used 36mm. The first test film is to determine the effective ISO many in the US would use a densitometer to do this, however it's easy to do visually and is described in Ansel Adams The Negative , or Minor White's books on the Zone Systen, it's well described online.

Then having detemined what you think is the effective EI you need to test to find the optimal development time usually to print at a specific grade on a chosen paper,, this is done by processing sections of the film (or different sheets) all given the same exposure of a test subject the for differing times. If the optimal development time is significantly different to the time used in the first test you may need to adjust the effective EI slightly. It's far easier to do than describe, I did my tests while living in Turkey with no access to a darkroom and my Foma films all printed easily with excellent results when I was next back in the UK.

As a guideline most users of Fomapan 100 & 200 shoot at half the box speed and development times are about 75% less than other films as Foma films build up density and contrast very quickly during development and you need to tame the contrast.

As your scanning I'd suggest that you need to adjust the development times to match the best negative you have made on other films, I matched my Foma films to Tmax 100 negatives that I knew were good.

Ian

[LabRat]

As a guideline most users of Fomapan 100 & 200 shoot at half the box speed and development times are about 75% less than other films as Foma films build up density and contrast very quickly during development and you need to tame the contrast.



Ian

Correction needed that the dev time is about 75% less than other films... (Now that's a short development!!!) :-)

The times match up fairly close to Agfa APX100 also as a starting point...

Steve K