Test Report: Automated Reading Densitometer X-Rite 890

[ic-racer]

Thanks to forum user "Bill, 70's military B&W", I have an X-Rite 890 to test. This is an automated densitometer into which one feeds a test strip of either film or paper, and the machine spits out the strip and records the densities in its memory. It takes less than 5 seconds to read a 21 step film exposure.


These automated densitometers show up on e-bay with pretty low selling prices. That, coupled with a potential time saving advantage, made me want to try out the 890 and see if it has any use in a contemporary B&W darkroom.

83179
83180

[ic-racer]

The manuals are available for download here:
X-Rite 890 Operation Manual: http://www.xrite.com/documents/manuals/en/890-500_890_Scanning_Densitometer_Operation_Manual_en.pdf
Test Strip Format Guide: http://www.xrite.com/documents/manuals/en/880-602_880-890_Series_CS_Format_Guide_en.pdf

[ic-racer]

Although the 890 is designed to read a series of pre-exposed control strips, it also has a capacity to read generic control strips that you make yourself.
It will read generic paper or film control strips.

CAVEAT #1: It needs a test strip exposure with the density patches at least one-half inch wide, without numbers. The recommended step wedge is the Kodak No.3 Step Tablet which cost $113 from B&H. None of the standard inexpensive Stouffer step wedges are wide enough once the numbers are cut off.

CAVEAT #2: Although there may be a clever work-around that I have not discovered at this time, it appears that calibration requires the X-rite 880-100 calibration strip (still available new from X-rite).

[ic-racer]

Fortunately I happen to have a Kodak No. 3 Step tablet. I'll fire off a few test exposures and see how the results recorded by the X-rite 890 compare to my other densitometers.

[Leigh]

The recommended step wedge is the Kodak No.3 Step Tablet which cost $113 from B&H.
That's for the uncalibrated one. The calibrated one is $270. :eek:

Looks like a nice densitometer.

- Leigh

[ic-racer]

Looks like I was missing a "1" the Stouffer website. They do have a wedge similar to the Kodak No. 3. It is number T2120. The specs show it is one-and-three-eights wide (Looks like 3/8" on the website) and nine-and-one-half inches long. I suspect it has numbers on it, but based on the size those could be likely cut off and still leave at least 1/2" of width. The T2120 is $29.

A calibrated wedge is not needed because the device won't calibrate to a generic wedge. It will only calibrate to the 880-100 which is a reasonable $35.

[ic-racer]

Another issue cropping up is that a step wedge with those big patches won't fit entirely on the platen of a Wejex or EG&G sensitometer (which is only 4.75" long).

To use one of those sensitometers to make an appropriate control strip to be read by the 890, one would need a 10 step wedge with 0.3 log d steps that is about 4.5" long and about 1" wide.

[ic-racer]

Reading through the Test Strip Format Guide I see a clever solution. Cut the 9" 21 step wedge into two pieces. Then do two sequential exposures on the EG&G. That is, make two control strips (high values and low values). Then feed them sequentially through the 890 to automatically read them.

[ic-racer]

Looks like my Kodak step wedge is a No. 2 (4"), not No. 3 (9"). The difference is vital to the test here. We need the big 10mm long density patches of the Kodak No. 3 (or Stouffer T2120).

[Bill Burk]

Which one is 3/4 inch by 4 3/4 inch for the EG&G?

[polyglot]

I have an 890 but haven't tried it out yet because of the patch-size issue. However you don't need to cut the side off a wedge to hide the numbers, you just adjust the guide rails so that the numbers are out of the reading area.

I have the little Stouffer wedge where the patches are too small and the strip is not wide enough. I plan to tape it to some paper so that it feeds cleanly but haven't tested that yet. I also suspect that the patch-size issue can be solved by putting a smaller mask in the densitometer so that it can see only a small piece of film. That will change the readings of course, but readings are effectively relative anyway.

PS: I highly recommend the "Edit Post" button. Means you can append stuff instead of putting up 50 posts.

[ic-racer]

However you don't need to cut the side off a wedge to hide the numbers
One issue is the numbers showing up during sensitometer exposure. The step wedge cannot easily be taped and masked on the sensitometer platen because of the need to take it off in the dark and put the other half on. I was thinking of taping each half of the split 9" step wedge on each long side of the sensitometer glass so it opens up like a 3-way fold out. Then I can fold down each half of the step wedge easily in the dark.


I have the little Stouffer wedge where the patches are too small and the strip is not wide enough.

I plan to tape it to some paper so that it feeds cleanly but haven't tested that yet.

I have tried that and it reads most of them, then gets off track and skips some. The ones that it does read seem to match pretty well with known values.

I also suspect that the patch-size issue can be solved by putting a smaller mask in the densitometer so that it can see only a small piece of film. That will change the readings of course, but readings are effectively relative anyway.

Yes, the reading orifice on my other manual units can be varied in size. However, I think the 890 already reads a slit opening and another solution might be to slow down the transit motor.




PS: I highly recommend the "Edit Post" button. Means you can append stuff instead of putting up 50 posts.
You know that button goes away after a while. You have not typed 500 words into the box and have your internet connection fail? :) Since the storm, it has really been hit-or-miss if I am connected at any given time. You really read those huge single posts anyway? :)

Maybe it is just me, but I see the 'post' as a conveyer of a single idea, like the modern equivalent of a 'paragraph.'

[erie patsellis]

Great densitometer, I used mine regularly when I processed a lot of C41 at home.

[ic-racer]

Which one is 3/4 inch by 4 3/4 inch for the EG&G?

Kodak No. 2 ( same as Tiffen No. 2, $102) has a shaded area 1" by 4" and no numbers
Stouffer T2115 is about the same length but only 1/2" wide and has numbers. It is the best value at $6, everyone should have one :)

Again neither of those has steps big enough to make a control strip that can be read by the 890.

[Bill Burk]

You _could_ make your own by projection. The "master" could be "calibrated" by you. Then the actual densities of the resulting strip could be plugged into the spreadsheet or graph...

[ic-racer]

You _could_ make your own by projection. The "master" could be "calibrated" by you. Then the actual densities of the resulting strip could be plugged into the spreadsheet or graph...
Yes, if you have a characteristic curve for the film onto which the step wedge will be created you could calculate the exposure needed for each step to get the density interval to be about 0.15 log d. One way would be to modify the advance and film gate of a 35mm camera to expose each step of the wedge.
However, $29 to have Stouffer do it for me is not too bad :)