Macbeth TR1224 Densitometer Calibration Standard / Card

I'm hoping an Apug member uses this model ( TR 1224 ).......

I don't have the original transmission calibration standard for my densitometer, I will purchase a Stouffer T5001C to replace it, the TR 1224 instructions show that the original calibration card had a single value only ie; 3.14D although it states that this value will change on different calibration cards.

My question is if you have the TR 1224 and the original transmission calibration card, what is the target reading ?

I'm wondering what density ( approx ) I should use from the Stouffer wedge, I believe that to have a linear calibration it would require 2 readings, one would be a clear air read and the other a reasonably high density ( 3.00D )

Any help appreciated.....

A 21 step wedge (T2115C) may be more useful. Not only can you use the last step for your Macbeth calibration, but you can use it in a sensitometer so you can make H&D curves.

Macbeth TR 1224

I have 2 or 3mm apertures so I would say I can read smaller step wedge areas ( 21 step ) so it would make sense and I see there isn't much cost difference between them...good idea, thanks ;-)