Recommended Densitometer

[NortheastPhotographic]

There are a lot of densitometers on eBay for some pretty good prices. It's hard to know what to choose! Anyone have a recommended model? I'd like to read C41 control strips as well as develop a characteristic curve for my B&W films.

If I do purchase a densitometer, is there any way to check calibration, or to calibrate the thing myself?

Thanks!

 

[Chan Tran]

I would recommend the Xrite 810 (or 811). It's a color reflection/transmission densitometer. You would need a calibration film for transmission and plague for reflection calibration. In fact calibration should be done very often.

 

[georgegrosu]

I've been working for 8 years with X-Rite 310 densitometer.
The densitometer had a calibration sensitogram.
At first, I checking the densitometer calibration for about a month, and then checking it less often.
Sure, if you have a sensiogram problem, the simplest thing is to check if the densitometer reads correctly.
Previously Iwork on the MV 4 DEFA densitometer at which about five years the bulb was burning and the densitometer was calibrated.
Densitometers are stable devices and you need to be very confident with he.
Any densitometer that reproduces the correct values is good.

George

 

[Mr Bill]

For color neg you want what is known as "Status M" (reversal films need Status A) - this is a specific set of spectral responses for red, green, and blue. Densitometers that have these almost always have a separate "visual" channel that approximates our visual sensitivity - this is best for B&W film. But in truth, any one of the color channels will give nearly identical readings for normal b&w.

I've used a lot, but quite a while back. In the US, the Macbeth machines were the cream of the crop, but I think I'd avoid the oldest ones, with nixie tube or dial displays. The X-rite 810s were great in the minilab days - they read all three colors at once, no rotating the filter turret like on Macbeths. Plus, the 810 can read "reflection densities," on paper. Be aware that the lamp in the head of 810s is special, and I think they are very expensive nowadays, so it may not be worth buying one with a blown bulb (check lamp pricing first).

Regarding calibration, you normally set "zero" with no film in place, then there is a "slope" control to dial in the higher readings. So all you really "need" is a moderately high calibration patch. As a fallback, you could just use a piece of b&w film with a fairly dense patch, and ask someone in a trusted lab to read RBG values for you. (Xrite 810 lets you enter the specific calibration values you want.) Or as a very crude check, read a neutral density filter (the thickness of the filter will mess up the light-handling geometry in the head).

There are a number of automated "strip readers" made to help automate control strip readings, but you need to be plugged into a machine with software to read it - I don't know what would work for a standalone application.

Ps, absolutely correct calibration is not too important for control strip readings, because of the way it's done. If you have a test strip density of, say, 1.50, you're not concerned with whether that value is absolutely correct - you're concerned about the difference in readings between the "reference strip" vs the one you process.

Happy hunting, hope you find a good one.

 

[Bill Burk]

I would purchase a T2115-C from Stouffer both as a calibration reference at a good value, and to use for tests.

Personally I shop by price and fix as needed. The X-Rite has a weird expensive light so make sure it hasn't been taken out or that the unit won't read.It looks like the cheapest ones on eBay are seriously damaged.

 

[RalphLambrecht]

There are a lot of densitometers on eBay for some pretty good prices. It's hard to know what to choose! Anyone have a recommended model? I'd like to read C41 control strips as well as develop a characteristic curve for my B&W films.

If I do purchase a densitometer, is there any way to check calibration, or to calibrate the thing myself?

Thanks!

Bill, I owned two different models so far.my first was made by Agfa;my current is made by Heiland in Germany;both can be calibrated by the user; they came with density targets;But of course, you can always get a Stouffer step wedge to check them.If you want to read transmission densities; it helps if they have their own light sourced if you like to read print densities' the head should be removable to reach all areas of a large print.good luck;I swear by them; a valuable piece of equipment for all photographers who do their own processing.

 

[Chan Tran]

With my Xrite 810 to I have the calibration film and the plague from Xrite. However if you can obtain accurate film step wedges you can use them.
The procedure for calibrating the transmission function is to first set the densitometer on calibration mode. Set the values for your standard which should be around 3 density for all channels. Then take a reading of nothing and next take a reading of the standard. The meter would make the calibration automatically.
For reflection use a plague with a white area of .10 density or less and the black area of around 1.80 density. Set the target value. Read the white spot then read the dark spot. The meter should calibrate itself.

 

[georgegrosu]

By the 1980s, Orwo sent us tests stripe exhibited by they, developed by they and read by they, plus sensiograms exhibited by they which we developed and traced the characteristic curve.
Because our densitometer did not match the Orwo readings we made a "translation" of the readings table.
We took the sensitogram exhibited, developed and read by Orwo and passed it to a table.
This sensitogram was read on our densitometer and the values obtained were passed to a column next to the initial table.
In order to have all densities, the density values were interpolated in both the densities column read by Orwo and in the density column read by us.
In this way we could present a sensiometric curve aligned with Orwo readings.
If you can not calibrate a densitometer perfectly it is not a big tragedy.
It is important that the densitometer be reproducible in readings.

George