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Seeking an Alternative to Color Densitometer Transmission Calibration Strip

LomoSnap

Member
Joined
Apr 19, 2023
Messages
61
Location
China Nanjing
Format
Med. Format RF
I recently bought a color densitometer, but it does not come with a transmission calibration strip. I am looking for a transmission calibration strip with color reference data like the Xrite 810-88.
I tried using a Stouffer for bw density calibration, but there is no color density reference.
Are there any transmission color calibration strips still in production?
 
LomoSnap said:
I tried using a Stouffer for bw density calibration, but there is no color density reference.
Click to expand...

You can get in the ballpark by assuming (yes, dangerous) that the Stouffer is neutral density. Visual inspection suggests it's fairly close to neutral, so has a practical workaround until you find something more solid, it may be an OK starting point.

LomoSnap said:
Are there any transmission color calibration strips still in production?
Click to expand...

I think they were often specific to the device or at least product family.
 
What densitometer do you have ?
If your machine has pre-set controls to calibrate zero level on each RGB channel and controls to calibrate slope, you don't need a colour strip, just a calibrated absorber ( ND filter ) to set the slope.

John S
 
John Salim said:
What densitometer do you have ?
If your machine has pre-set controls to calibrate zero level on each RGB channel and controls to calibrate slope, you don't need a colour strip, just a calibrated absorber ( ND filter ) to set the slope.

John S
Click to expand...
I have an ESECO TR90 densitometer.
It can be zeroed without film, then calibrated at about 3.0D and the reference density entered, it does not have a manual slope setting.

You mentioned using ND filters for calibration, which is indeed an idea, but I think even very high-quality ND filters will not attenuate the three colors of light in exactly the same way.
 
What koraks wrote; see my calibration target is close to ND:

Tobias Densitometer Tune Up

I was doing some year-end cleaning and got out my spare densitometer for a checkup. Seems to work OK but the button did not work all the time. Thanks to Mouser's extensive database of switches, I was able to get an exact replacement.
www.photrio.com
 
The one company I'm aware of that makes replacement calibration references for these densitometers is Acurad.

As far as assuming any sort of B&W film based reference is "neutral" density, that is a dangerous assumption to make. I have a whole bunch of transmission wedges and references myself, and while some are close to neutral, some are very much not neutral.
 
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