View Full Version : Pyrocat-HD & densitometer reading??

Bob Farr
21-Sep-2011, 09:36

My question is; "What density readings should I be getting with HP5 and Pyrocat-HD??"
I've just completed a film test with HP5 and Pyrocat-HD [1:2:100] at 75 degrees using BTZS tubes. Developed for 5, 7, 10, 15 and 20 minutes.

Am using the blue channel on my 310 X-Rite. The densitometer was completely rebuilt by X-Rite 3 years ago and calibrated before reading the film densities.

The Dmax for each are as follows; 0.31, 0.38, 0.45, 0.52 & 0.57.

These seem rather low and was wondering how they compare with what others have experienced??


21-Sep-2011, 10:27
Are these reading transmission Dmax? If so, something is wrong as they are way, way off. A blue channel reading of HP5 in Pyrocat 1:2:100 for 20 minutes at 75F should give a reading of over log 2.5.


Bob Farr
21-Sep-2011, 10:32
Hi Sandy,

I questioned my readings. My assumption and hope is that the densitometer is incorrect.


Paul Bujak
21-Sep-2011, 12:13
Do you calibrate with a step wedge?

Bob Farr
21-Sep-2011, 13:32
Hi Paul and Sandy,

Realized that I'd calibrated the densitometer incorrectly. So, I now have a Dmax, step 1, of 2.46 on HP5, P-HD [1:2:100] at 70 degrees F.

Thanks to both of you for helping me with this.