calibration procedures for Macbeth TD500

[rickwinkler]

I've taken a chance on an analog densitometer, the Macbeth TD500. I've used a densitometer over 15 years ago but never calibrated one. Can anybody point me in the right direction to get the procedure to calibrate it. I did purchase the Stouffer step wedge with 21 steps and the correct value for each step.

[Gord Robinson]

Normally the densitometer comes with a calibrated calibration strip. If yours does not have one then you would need to have a step wedge with know values. What follows should get you on the right track. It is from memory so if it doesn't work maybe someone else can correct it.
Normally you would turn the densitometer on and let it warm up. Depress the snout onto the lighted disk and with the zero control bring your reading to 0. Place your step wedge onto the disk and use a patch on your step wedge of about 2.8 and depress the snout on this patch. On the back of the densitometer there is a knurled cap on the calibration knob that you can remove to adjust to bring your reading to match the patch on the step wedge. Once these numbers match check another patch in the range of about .35 to see if your reading match. Macbeth had 3 disks with holes of 1mm, 2mm and 3mm depending on the size of area you wanted to read. If the densitometer does not have a built in voltage stabilizer it is a good idea to run the unit through one so that your readings are constant. It is a good idea to check the calibration against your known sample if you are using it for any length of time.

Hope this helps

Gord

[Craig Schroeder]

I saw your post on another forum regarding this and went looking for a pdf that I once had for the operation of your Macbeth... I can't find it, I'm afraid. I'm writing because I wanted you to know there is such material floating around the net but I don't recall where I got it (it was a few years back). I recall corresponding with a former technician of Macbeth's and perhaps it came from him. Perhaps someone else has had connections with him as I recall that he was somewhat active on a few forums back then.

[rickwinkler]

Thanks Gord and Craig. I went through the steps mentions and to my surprise this thing is calibrated. I didn't need to adjust it using the knob on the back.

Craig, I have searched high and low and found nothing as well. Please let me know if it ever shows up.

[Helen Bach]

Here's the 900 series manual.

Best,
Helen

[Roger Thoms]

Helen, Thank for the attachment, I just got a TR924 and I'm trying to figure it out.

Roger Thoms

[Helen Bach]

Feel free to ask any questions. I still have my TR-924.

Best,
Helen