Film speed

[Terry Hull]

I have never gone through the discovery of my own film speed, because I print in two different rental darkrooms, one with condenser enlarger, and the other with diffusion enlarger. I do know that it seems to work better rating FP4 at less than its indicated speed. Any suggestions on more specific ways to approach this problem? Due to logistics involved I will continue to use both darkrooms.

Thanks.

[BetterSense]

It's not that big of a deal. I use variable contrast paper and print indifferently on my condenser and diffusion enlargers. Since I have work up the correct contrast for each print anyway, I don't bother to tailor my negatives for one or the other.

[Peter Mounier]

Film speed is mostly evident in shadow detail (or lack of) in the negative, rather than contrast in the print. If you're continually asking yourself why your prints don't have enough shadow detail, you may want to adjust your film speed, as you've done by lowering the speed when you use FP4. Using variable contrast papers should be enough to get great prints no matter which enlarger you use.

Peter

[ki6mf]

A good tutorial can be found at http://www.jerryo.com/teaching.htm Jerry covers testing for film, ISO etc and covers:

• Finding your Normal developing time
• Using a densitometer
• The Visual Method
• The practical method
• Finding N+ and N- developing times
• Using a densitometer
• The Visual Method
• The practical method

[Jim Noel]

I have never gone through the discovery of my own film speed, because I print in two different rental darkrooms, one with condenser enlarger, and the other with diffusion enlarger. I do know that it seems to work better rating FP4 at less than its indicated speed. Any suggestions on more specific ways to approach this problem? Due to logistics involved I will continue to use both darkrooms.

Thanks.

Your use of two different darkrooms is no reason not to define your own film speed and development time.

[ki6mf]

I have never gone through the discovery of my own film speed, because I print in two different rental darkrooms, one with condenser enlarger, and the other with diffusion enlarger. I do know that it seems to work better rating FP4 at less than its indicated speed. Any suggestions on more specific ways to approach this problem? Due to logistics involved I will continue to use both darkrooms.

Thanks.

Film speed deals with calibrating your choice of developer/chemistry and film to the light meter you use! The problem you have with two darkrooms would be if you use different film and developer combination's. The instructions posted in this thread will let you determine what ISO to use. It will also step you through how to optimize the image on your negative. To be accurate you must use the same developer and film and not mix and match them.

[Heroique]

I have an Omega D2v (condenser) enlarger, but often use my Omegalite (diffusion) head.

The condenser head, thanks to the so-called Callier effect w/ certain negatives, preserves far fewer distinctions in my highlights than the diffusion head, but the condenser head also provides unique benefits of its own.

These facts in the darkroom influence my decisions in the field...

For example, part of my “pre-visualization” process is to decide – before the shot – which enlarger head is more suitable. (This, of course, is just one decision I’ll make about my future steps to the final image I want.) Depending on the shot, this decision can be critical; other times, it makes little difference. When it’s critical, I’m typically left w/ a choice between two exposures, and they can differ significantly.

Long story short: Try to coordinate your metering w/ every step you’ll take toward the final image you want. All of this requires plenty of experimentation, calibration, and practice – but the hard work leads to a pleasing consistency, and pays big dividends in satisfaction. (Simmons’ Using the View Camera has a helpful section titled “Establishing a Personal Exposure Index.”)

Now for a key qualification: Always shooting “box speed” produces fewer problems than forums like this will have you believe.