Noritsu DM-1 densitometer calibrationgreenspun.com : LUSENET : Large format photography : One Thread
I have recently bought a used Noritsu DM-1 transmission/reflection densitometer without instructions and wondered whether any of you out there have used this or a similar machine and know how to use/calibrate it.
I have tried websearches on Noritsu, both UK and USA and I cant find anything about densitometers, only mini-labs and other stuff.
The densitometer appears to work OK. If I set it on "V" (dont know what this is, I only know the other three settings are colour channels) and use the "transmission" setting (this is the setting I'm interested in) it displays values that agree nr enough with the steps on my uncalibrated Agfa step tablet, i.e.: 0.15 steps.
I know that for comparative purposes I only have to subtract the a film-base + fog reading from other readings to find the range of a neg, but I would like to be able to calibrate it. It comes with a sort of calibration device cocnsisting of a wafer with one opal and one dark round lens and someone has recorded values against each - any ideas what this means?
Thanks for your time.
-- Neil Miller (email@example.com), April 04, 2002
I assume that the two filter device you have is for calibration, and the numbers written on it are for calibration purposes. I picked up a densitometer (made by Nuclear Associates, for x-ray machine calibration, runs on batteries) and wrote the manufacturer. For a hefty price I got a calibrated wedge. It is normal for the factory calibration to be hand written. Turned out it device was right on the money but at least now I know that. I suggest you zero it out, then test the two filters you have and see if what you get it close or the same as what is written on them. Make adjustments to get there. If you do this, when you zero out B+F and then measure you should be accurate. If one of the known values on the calibration is the 0.10 you're looking for on a film speed test, that would, of course, be the value to adjust to as close as you can get so you're reading right in the middle of the most accurate calibrated range. Note the measurement of B+F (slightly different for different film and developer combinations) before you zero that out for an actual test of the exposed film density. Going from memory, if it's not something like 0.06 to 0.10 for B+F before you zero out the clear processed film then something is wrong.
-- Kevin Crisp (KRCrisp@aol.com), April 04, 2002.
Neil, there's a good liklihood that it's an X-Rite 810 or very similar. A post at the following location may be helpful. Someone had also put a link to download a manual.
PS: the 'V' probably means "visual" density. It has a much wider spectral span and is generally considered to be the best one to use for general B&W work.
-- Bill C (firstname.lastname@example.org), April 04, 2002.
I have a manual for an XRite-810 model. If you think that is what you have or could send me a picture of yours I may be able to help you.
-- James Phillips (email@example.com), April 05, 2002.