Density measurement of Pyrocat HD negatives?

[Bill Kumpf]

I am working my way through “Beyond the Zone System”. My goal is to reduce the variables in my darkroom set up and my process. I have reduced the potential for film fogging, standardized film test film exposure, and charted a few graphs. I am using a Pentax analog spot meter for density reading. Ilford FP4+ film has been processed in 1 gallon tanks using Xtol 1:0.

In the past, my standard developer has been Pyrocat HD. What procedure do I need to measure density of the stained negative?

Thanks for your input.

[Drew Wiley]

You need to filter out the stain. The problem with using a blue gel filter to do this is that it will introduce so much extra density that few if any densitometers have
the light intensity or surplus range to give you a plot afterwards - so there goes that hypothetical solution, which I mention simply because one finds it in print so
often, even though it's not practical. XRite did make a special model b&w transmission densitometer which would be appropriate. They come up for sale from time to
time. You might ask Sandy King on this forum or on his carbon printing forum, where they are more commonly used. Or you could just take your readings "as is" and
realize they are distinctly skewed. It really sounds like overkill to me. .. more trouble than it is worth. Practice printing with test strips will get you from point A to
point B faster. Fog usually shows up on the edges of the film and is the fault of improper development.

[sanking]

I am working my way through “Beyond the Zone System”. My goal is to reduce the variables in my darkroom set up and my process. I have reduced the potential for film fogging, standardized film test film exposure, and charted a few graphs. I am using a Pentax analog spot meter for density reading. Ilford FP4+ film has been processed in 1 gallon tanks using Xtol 1:0.

In the past, my standard developer has been Pyrocat HD. What procedure do I need to measure density of the stained negative?

Thanks for your input.

You should measure the density of a stained negative in a wavelength that corresponds to the sensitivity of the printing process. Most alternative printing processes are sensitive to UV light so the test negatives should be measured with a UV densitometer. Graded silver papers are sensitive primarily to blue light so use a densitometer set to blue light. Variable contrast silver papers are sensitive to both green (low contrast) and blue (high contrast) light so neither green or blue reading will be perfect, generally people use blue readings and live with the slight loss of precision.

Sandy

[Bill Burk]

I think that Drew Wiley is probably right on this one, you can examine your current tests that you did with the standard developer using the spotmeter as densitometer rig from BTZS... But then adjust your density scale for Pyro use according to two side-by-side contact prints from step wedges from a standard developer and from a Pyro developer... Under your intended enlarger light source onto your intended paper... You'll be going Beyond the Beyond the Zone System.

After all, the purpose of a densitometer is to predict how something will print. So a print can be an effective substitute for a densitometer.

[Bill Burk]

You should measure the density of a stained negative in a wavelength that corresponds to the sensitivity of the printing process.

I like the simplicity of that advice.