Should I bother with BTZS?

wm blunt said:

You can skip a lot of the testing by contacting The View Camera Store and have them do the testing for you. They send you several sheets of your film type exposed with a step wedge and you develope the sheets, return them and they read and plot the densities. They send you the results. Also you can use the BTZS power dial instead of a palm pilot. It's a small cardboard device that used either zone system or incident metering. A pretty inexpensive way to get into BTZS.

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This also sounds like a great idea to me- the reason I've not even been touching BTZS is because I have no access to any kind of densitometer. Where would I find this cardboard dial?

Tim

timbo10ca said:

This also sounds like a great idea to me- the reason I've not even been touching BTZS is because I have no access to any kind of densitometer. Where would I find this cardboard dial?

Tim

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Tim
The View Camera Store has the "Power Dial", only about $10 or so I believe. They also have what they call BTZS Lite which is useful, it explains the system.

timbo10ca said:

Hi Larry-
As I do not have a densitometer, this sounds like a method that may help me. Could you please elaborate for me how you do it? I am currently thinking of buying a timer with an exposure meter that will supposedly act like a densitometer, but I can't see how it will do it accurately, as it is placed on the projected image (which may be at any brightness, depending on what the enlarger lens aperature is set at). Plus, I already have all the equipment you mention, other than the .10 neutral density filter- Is this the equivalent of a 1/3 stop ND filter? Where do you even find these?

Thanks,
Tim

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Density read by any means is a relative logarithmic measure defined as the logarithm of the ratio of incident light to transmitted light. Zero density is not zero light. It means that the light passing through whatever you are measuring is the same intensity as that falling on it. Zero is the log of 1. A density 1 unit above another transmits 1/10 the amount of light. A density of 2 units is a factor of 100.

If you set your easel densitometer to zero when there is no negative in the carrier, your meter will read the density at any point you desire of whatever negative you put in the carrier.

If the f-stops of your enlarging lens are accurate, you would see that a change of 1 stop, say from 4.0 to 5.6, is the same as putting a neutral filter of density 0.303 in the light path.

Thanks again everyone for all the perspective. I'll do a little more reading on the subject, but I'm probably going to end up doing it.

MVNelson said:

I borrowed the hospital's Xray dept densitometer.

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That's a great idea -- I hadn't thought of that. I'll try that if I end up doing BTZS.