Modern densitometer choices

Nodda Duma · Dec 12, 2019

dkonigs said:
I didn't miss what you replied to. Its just that their website provides so little information on what they actually provide with the calibrated step wedges. I just sent them an Email asking for more information (specifically about the RGB stuff), so I'll report back what I learn.

Awesome! Would be interested to hear what they say.

dkonigs · Dec 13, 2019

Okay, here's their reply:

Hi Derek,

I'm sorry but we do not have any transmission step wedges that have RGB calibration.

Sincerely,

Kevin Morris
Stouffer Industries

Not the least bit surprising, to be honest. What is surprising, is that I still cannot seem to find ANY new products that would clearly meet my needs. The closest I've come is vague suggestions to "ask a lab who has what you've been unable to find, to help you out." In all my furious searching, I did find one company (Acurad) who claims to service these older densitometers and provide test strips for them. We'll see if they respond to my inquiry.

This kinda screams for a DIY project, except that even a DIY project would still face the same calibration problems.

(At least for now, even if my 810TR isn't giving me "traceably accurate" numbers, its still useful in providing relative measurements... e.g. reference strip vs process strips, or paper base vs exposed area)

ic-racer · Dec 13, 2019

Just calibrate color channels to a ND filter. My calibration patch is made of B&W film, it is not technically Neutral, but the green matches perfect and the red and blue are pretty close. A true ND filter will show all three colors the same density.

Tobias Densitometer Tune Up

Bill Burk · Dec 13, 2019

Have you reached out to X-Rite? Let me know if you need an inside assist.

It’s not true that a neutral gray would read equally on the different channels. That’s why you see different readings written on the calibration scale. The scale itself will fade over time, but nowhere near as much as the effect of dust and grime on the optics. Filters inside the head will fade. Even the electronics will degrade over time more than that standard. There is only one thing that you can know for certain is correct. And it’s that standard, when it is new. But because your standard is old - you just have one more piece of uncertainty.

I think you will be able to trust your existing standard as far as your own “personal, educational” use goes. If your densitometer finishes its “calibration” routine today... great. Write down your results and be glad the machine did its job. It will be very good. I’d guess within +/-0.03 of “reality”.

The only time I fret over the inaccuracy of my measurements is when I am reading sensitometry strips that a friend developed. Then I go so far as read my calibrated scale next to the friend’s negative and interpolate the differences in readings. It’s messy but what I have to with my primitive tools.

In other words it only matters when you are doing it for someone else.

dkonigs · Dec 14, 2019

So I did reach out to a company that still services and supports these old X-Rite densitometers (Acurad, http://www.acurad.net/ ) and got a rather interesting and detailed response. The short version is that the only difference between the transmission calibration strips that X-Rite still sells, and the one for the 810TR (810-68) is the labeling and calibration numbers provided with it. So they apparently have a way to perform NIST-tracable calibration on their own set of X-Rite densitometers (from the 810TR's era) and will thus provide new test strips they make by calibrating and labeling the current X-Rite ones with the appropriate numbers for the older machines. They also will re-calibrate your old test strips. (And they also service/calibrate the instruments themselves.)

This still doesn't answer my question about actually wanting new products that will perform the same functions, but it does give me a way to have more confidence in my ability to keep something like the 810TR useful and sufficiently accurate for the foreseeable future.

radiant · Dec 14, 2019

I have been thinking making my own densitometer, just for my own reference (checking if my print has the paper dMax) but maybe it could be calibrated somehow. The idea was presented here (by who else than koraks ) https://www.photrio.com/forum/threads/diy-light-meter-for-darkroom.169398/page-2#post-2204322 - where I built a DIY darkroom meter succesfully. Not saying that DIY is an real option but just a notification for DIY'ers that it is totally possible to do a densitometer by yourself. Maybe not calibrated to standards but I am sure it works in my own reference scale.

AgX · Dec 14, 2019

By the way the way, the Heiland densitomerers come with both, a calibration transmission- and reflection-stepwedge.
(This is explicitedly stated for the white-light version, I assume this is true for the RGB versions too...)

Steve Vallis · Sep 20, 2020

dkonigs said:
I recently bought an X-Rite 810TR densitometer off eBay, and its been a very convenient tool to have around the darkroom. It can do both reflection and transmission, and can read color channel density (R/G/B) as well as "visual" density for B&W.
So far I've used it to help calibrate my RH Analyser enlarger meter and to inspect C-41 Process Control Strips (which I run to sanity-check my C-41 chemicals/processes). I may find more uses for it in the future. Regardless, I love having this piece of equipment that saves me from having to "eyeball it" on any task that involves comparing/verifying the density of a piece of film or paper.

Unfortunately, I'm quite concerned about the future-proofing of this piece of equipment. Replacement parts are hard to find (and/or extremely expensive if you do). Also, I don't think X-Rite even sells the transmission calibration step wedge for it anymore. (The one I have, that came with the machine, is very old and probably due for replacement.) I also sometimes question the absolute reliability of its readings, but it is probably good enough for now.

What I'd like to know, is whether there is any good "modern" (preferably LED-based) alternative that provides the basic capabilities of the 810TR. That means transmission and reflection, and RGB readings. Most densitometers I see out there right now are either single-channel (B&W), or color (and costing a fortune) with enough fancy features that I honestly cannot tell whether or not they'd do what I want.

I know that in our community, Heiland does make a densitometer that has many different options. But what I do not know, is whether or not it can be used (with the multi-color transmission light option) to provide RGB readings to evaluate those C-41 strips.

I found a link http://www.eseco-speedmaster.com/ST5specsheet.pdf would this help?

dkonigs · Sep 20, 2020

Steve Vallis said:
I found a link http://www.eseco-speedmaster.com/ST5specsheet.pdf would this help?

No. As far as I can tell, that's just an old product spec sheet of something that's not much different from what Stouffer sells off-the-shelf.

However, Acurad (company I mentioned in an earlier post) does sell new calibration step-wedges for the X-Rite color densitometers. I bought one from them, and it got the job done.

Of course the fundamental problem here is that I'm still not aware of any newer product that could take the place of these old X-Rite clunkers.

Steve Vallis · Sep 20, 2020

https://heilandelectronic.de/de_opt08 I'm not sure id the filters are status AorM

dkonigs · Sep 20, 2020

Steve Vallis said:
https://heilandelectronic.de/de_opt08 I'm not sure id the filters are status AorM

I also previously followed up on that one. They're clearly not designed for use as a color densitometer, and that feature is designed more for specific films that might need to be measured against certain colors of light. So its possible that it might work (or get close) by accident, but certainly not by design.

ic-racer · Sep 20, 2020

It is hard for me to imagine a new trash heap compliant (Rohs) product with surface mount technology being superior to an old 'clunker' with discrete components that was not designed for a trash heap.

dkonigs · Sep 20, 2020

ic-racer said:
It is hard for me to imagine a new trash heap compliant (Rohs) product with surface mount technology being superior to an old 'clunker' with discrete components that was not designed for a trash heap.

Its easy for me. Modern LED-based light sources and modern sensors aren't going to require constant faffing around to make sure they stay reliably in-calibration. Nor are they going to have the same sorts of age-related degradation/failure issues.

ic-racer · Sep 21, 2020

i'm sorry you had a bad experience with your older unit, I'd not call that common. One of my units had a loose connection on the power supply, that was easily rectified. Otherwise, I'm not familiar with any 'faffling around' to stay in calibration. I did have 'age related' issue with the light source, but was clever enough to unscrew the burned-out incandescent lamp and screw in a replacement.

lantau · Dec 24, 2020

dkonigs said:
That much I know. What I don't know, is whether it'll yield the same results as a color densitometer (that uses a white light) when I cycle through the different illumination colors. They provide so little information on this option on their web page, I don't even know how it works or is controlled.

A few months ago (probably around the time this thread was last active) I asked Heiland on their Instagram channel in a post with their densi. They replied that it couldn't be used for reading C41 control strips, because the spectrum of the four colour LED is not was is required. I read this as: it's not Status-M, you're on your own. According to the product page the colour version is useful for other non-photographic applications and possibly when reading b/w negatives made with staining developers.

AgX said:
By the way the way, the Heiland densitomerers come with both, a calibration transmission- and reflection-stepwedge.
(This is explicitedly stated for the white-light version, I assume this is true for the RGB versions too...)

I just bought the TRD-2 model (Merry Christmas!) and it came with calibration strips for transmission and reflective modes. Each has four values, including zero.

The reflective one looks like matte FB paper and has continuous tone grey patches.

The transmission wedge is film with halftone patches. I.e. dot pattern. I guess the dots are completely opaque.

I have the colour filters from a Kodak Model 1 densitometer. The ancient bakelite one. They are 1x1 cm in size, each. Filter sandwiched between two glass plates. Due to the halftone transmission wedge I read the exact same calibration values through all colour filters (after zeroing on the first one, of course). I didn't play with the reflective mode and colour filters.

But I did try a patch on my 21 step Stouffer wedge and did read different values for different colour channels. I zeroed with only the respective filter on the densitometer.

I'm writing this in this thread only for completeness. I'd like to continue the discussion regarding those Kodak colour filters in another thread called 'Flexicolor Reference: b-2020-c41.pdf' in the Color Forum. I'm wondering if those Kodak filters are Status-M or otherwise good enough to allow me to use C41 control stips. At least well enough to monitor a replenished process and see which direction it is drifting to. My home processing will never be as perfectly in control as it is in a Pro Lab, in any case. But I'd like to keep it good enough to use the negatives for colour printing.

Philippe-Georges · Dec 25, 2020

What about this one?

ic-racer · Dec 25, 2020

The main issue I have with my X-Ritge 880 is that it is very difficult for any of my 3 sensitometers to make the strips it needs. It is designed for commercial produced test strips.
It is not impossible, however. Do you have the manual?
This first example is the what is required if you want to try to create a commercially produced test strip:

ic-racer · Dec 25, 2020

If you look in the back of the manual, it shows how to make your own test strip that the machine will read. Realize they are showing this to test INTERNEGATIVE film, as they assume all other negative material will be tested with the commercially available test strips. Of course that is not the case, so you would use this method to test ANY film, not just INTERNEGATIVE film. This is not clear from the manual, so I'm pointing it out.
Otherwise one could read the manual and think the unit is useless without the commercially produced strips.

ic-racer · Dec 25, 2020

Some more information on reading "Generic" test strips:

dkonigs · Dec 25, 2020

michael_r said:
I might be misunderstanding what OP is looking for exactly, but Tobias seems to have some new products including at least one colour densitometer. Correct me if I’m wrong in this.

I'm looking for something (that's not a relic of the 80's on 3rd party maintenance life support) that can do Status A color reflection densitometry and Status M color transmission densitometry. (with Status A transmission being a bonus, but not a requirement)

Looking over the Tobias website, they do appear to sell (or at least support) a few densitometers:
In the reflection category, they have the IQ150/IQ200, which are Status T or E. (Color paper needs Status A)
In the transmission category, they only have the TBX1000C, which is Status A (Color negative needs Status M), though they do claim custom filters may be available upon request.

(Also in the reflection category, there is mention of the IQ1000/IQ1500/IQ2000 which can do Status A, but its unclear if this is a product they actually still sell. This info is buried in the product info for the IQ4000, and not linked to directly.)

So by the public information, which looks like something they had an intern with circa-1996 web skills haphazardly throw together, its unclear if they even still have products that could potentially do what I'm looking for. Its also unclear how anyone even buys their products (outside of establishing some sort of relationship with a middleman dealer).

Its also not clear whether these products are even still in production, or are any better or more reliable/servicable than an old/used X-Rite 810TR.

ic-racer · Dec 25, 2020

Request does not make sense. "Relic of 80s" will be repairable. Anything newer will be designed with the expectation that it will be E-trash in a few years and require regular replacement. Who would want that?

ic-racer · Dec 25, 2020

Hey, dkoings aren't you the one making the fantastic enlarger timer/meter. You can make your dream densitometer. If it is as nice your the enlarger meter, I'd even want one and I already have 3 different densitometers and 3 different sensitometers.

dkonigs · Dec 25, 2020

ic-racer said:
Hey, dkoings aren't you the one making the fantastic enlarger timer/meter. You can make your dream densitometer. If it is as nice your the enlarger meter, I'd even want one and I already have 3 different densitometers and 3 different sensitometers.

Believe me, the thought has crossed my mind.
The problem is that a densitometer (at least done right) requires a fair bit of care and attention to the optical path. There's also probably a fair bit of calibration necessary to get good results. Finally, spectrum matters, and the parts you'd use aren't always designed for people who care about such things.

That being said, I am somewhat curious about what the cross-section of the Heiland TRD-2 looks like. It does seem like a far simpler (and more modern) design than most of the serious densitometers. However, it doesn't do color, and is essentially useless for "absolute" density measurements. (It works great for relative density, compared to paper or film base, however. That being said, when calibrating my enlarger meter, I do want relative density. But when measuring process control strips, I'd rather have absolute density.)

Finally, I've recently felt that I should add a sensitometer to my collection. It would certainly make B&W process control a lot easier. (As the only off-the-shelf strips still sold are for Ilford FP4, and currently out of stock in the usual places.) The struggle there is deciding which one to actually buy, since most of the obvious hits are for blue/green units designed for different purposes. (And it doesn't help that the majority of existing forum threads on this subject are clogged full of people who think the OP is asking about densitometers, which ends up derailing and confusing the majority of the conversation.)

dkonigs · Dec 25, 2020

michael_r said:
When I looked into sensitometers several years ago (including designing my own, which I never built), aside from the blue/green type I don’t remember there being anything current besides the Wejex. If you find anything I’d be curious.

Honestly, I'd even be fine with old and used. I just don't know what keywords to be searching for. (given that nearly everything I find is blue/green, and its unclear if that's a good or bad thing, or if it requires modifications)

ic-racer · Dec 26, 2020

I'd be more concerned with the light path of a sensitometer. For example the light path of the Tobias densitometer is pretty simple. A reflector lamp, small diffusor and the sensor with a rubber o-ring to keep stray light out. It is adjusted for optimum performance by moving the lamp up and down.
The same company (Tobias), in the construction of their sensitometer, has a special design diffuser, a long light path, to minimize cosine, a stepper motor with shutter. In fact the majority of the construction of the sensitometer is the light path; there is not much else in the box.

In a nutshell, the densitometer light path only has to be repeatable and stable, not neccessarily even as long as the target patches are even. Since it can be zeroed before each reading, repeatability is easier to design into the system.

The sensitometer light source has to be perfectly even throughout the entire length of the step wedge. This is a formidable task. And it has to be more perfectly repeatable.

I compared all my sensitometers here:
https://www.photrio.com/forum/threads/the-great-sensitometer-shootout.95837/

Modern densitometer choices

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