Macbeth Densitometer Readings

[YCG]

Hello,

I have a Macbeth TR1224 densitometer. I want to use it for light transmission measurements of plastics after some processes.

I have successfully calibrated it with Stouffer step wedges. I am getting four readings R-G-B-V. From which I understand, I should consider the value V(visual). Sadly I could not find a decent document to clarify it, and the Macbeth manual is not that user friendly.

Could someone help me with this?

Thanks a lot.

 

[Bill Burk]

Yes the V is visual channel.

Edit: the following is all wrong (it’s a 106) but leaving it up as a reminder of my misconception….

It has a Wratten No. 90 filter over the photomultiplier tube sensor.

Not surprising that’s the same filter used in Zone VI viewing filters. I think scientists selected its properties of reducing colors to visual monochrome before Ansel Adams decided it does a good job of previewing how things would look in black and white.

 

[Saganich]

Yes, V is for visual. On the older Macbeths, it was the gold dot on the dial for transmission and black dot for reflection.

 

[ic-racer]

What color is the plastic? What is your intention with the measurement?

 

[Bill Burk]

Yes, V is for visual. On the older Macbeths, it was the gold dot on the dial for transmission and black dot for reflection.

View attachment 290587

Ok I am wrong. It’s a 106 not a 90

 

[Saganich]

Ok I am wrong. It’s a 106 not a 90

I hadn't seen your post before I added that old table, but I think the two filters differ only regarding the properties of the particular photocell used at the time. Likely current or less ancient machines use the 90. My old Macbeth manual actually states the 106's are different for transmission and reflectance and warned about interchanging the wheels.

 

[Bill Burk]

I think I got my impression from taking apart the densitometer for cleaning and what I saw looked like a 90. Even my instructions manusl mentions the 106 and Kodak Filters says the 106 is for visual readings in densitometers… while the 90 is for monochrome viewing.

I’ve been wrong before but this time I made the whole thing up.

 

[YCG]

Thanks a lot for your answers.

What color is the plastic? What is your intention with the measurement?

Plastics are clear (PMMA, Polycarbonate etc.). I want to measure the transmission properties after some type of processes. But the main idea is it still good to see through or not.

 

[ic-racer]

...see through or not.

So, if 'seeing' is important, I'd think that all the colors would be important, so I'd test with all 4 channels.

 

[Arthurwg]

"Is this a densitometer I see before me? Come, let me clutch the."

 

[YCG]

So, if 'seeing' is important, I'd think that all the colors would be important, so I'd test with all 4 channels.

Thanks for the reply

 

[YCG]

"Is this a densitometer I see before me? Come, let me clutch the."

 

[Leicabimmer205]

Does anyone out there have a instruction manual for the Macbeth TD-902 densitometer. I found a pdf for the TD-903 and TD-904 but nothing on the TD-902. Was it a European market designation perhaps? Also, would the instructions for the TD-903 be the same or similar to the TD-902? If someone has a 902, is it 230V?

 

[craigclu]

I have a 902. I use a Stouffer step wedge for calibration.

https://www.stouffer.net/TransPage.htm

You may already have this piece (attached) but in case you don't.... I thought I had more than this as a retired Macbeth tech sent me some things many years ago. I'm afraid it was lost in a computer crash long ago.

 

[Leicabimmer205]

Thanks so much for your reply and the pdf. As it happens I have a copy and can't find any references to the the TD-902 just the TD-903. In your experience are there operational differences between the 902 and 903 or can I apply the instructions for the 903 to the 902. Also is yours 240V or 110V? Thanks again.

 

[craigclu]

Mine is a 110v... I haven't used it in years and don't trust my memory as I write this. I have an obscure Wallner rig in my darkroom that agreed with the 902 and does some other things for me and gets used these days. One thing I recall is that it was recommended to allow a minute or so of warmup for the bulb to stabilize before running the calibration..