Re: Need Guidance on Getting a Sensitometer
Hi Greg, the way that I read IC-Racer's tests on the LED Blue/Green Sensitometer's via the Photrio threads was that they performed properly for him in regards to the full range of tests and validated across multiple films and developers. I assume he had to figure out exposure time and illumination or he could not have constructed the characteristic curves. It would be good for IC-Racer to comment on this specific thread for clarity.
I am a novice at this, so I may be missing something or possibly misunderstanding?
Quote:
Originally Posted by
Greg Davis
The blue and green X-ray sensitometers will be useful for comparing different films, but may not be full spectrum enough for contrast index, accurate film speed, etc. And they may not have a means of measuring illuminance. There are three EG&G units on ebay right now that are 5500K flash units and discussed in IC-racers threads on Photrio. They may need work on the electronics though.
Re: Need Guidance on Getting a Sensitometer
Hi, did you see Greg's comment about this earlier in the thread?
With being a novice at sensitometry, I am trying to make sure I am clear on these issues so I can go buy a unit that not only works, but will perform across the full ranges of tests.
Here was Greg's earlier comment: "The blue and green X-ray sensitometers will be useful for comparing different films, but may not be full spectrum enough for contrast index, accurate film speed, etc. And they may not have a means of measuring illuminance. There are three EG&G units on ebay right now that are 5500K flash units and discussed in IC-racers threads on Photrio. They may need work on the electronics though."
Thoughts on this based on your tests?
Quote:
Originally Posted by
ic-racer
Re: Need Guidance on Getting a Sensitometer
Did you read the manual I posted?
Here it is again
https://www.xritephoto.com/documents..._Manual_en.pdf
Quote:
Originally Posted by
LFLarry
Randy, the issue with the X-Rite densitometers is they don't publish the exposure time or the illuminance value of the light source, both of which are needed to build characteristic curves. Based on the info from IC-Race, the Blue & Green LED units will work for B/W film exposure. I wonder if the exposure time and illumination value is provided with the calibration data?
Re: Need Guidance on Getting a Sensitometer
I have not tested the response of Fomapan but I'd probably use the Blue LED to compare it to the other films for speed. In terms of making processing control strips to monitor development, the color should not matter per graph 1.
Re: Need Guidance on Getting a Sensitometer
Hi, yes, I did read the manual, twice actually, and I even searched the PDF as well to ensure I didn't miss anything.
I can't find anywhere in the manual where it specifies the exposure time or the illumination value of the light source for any of their units. I even went and looked at other X-Rite units and nothing there as well.
I also read the full list of specifications and nothing there as well.
If I am overlooking something, please point me to the page please.
Quote:
Originally Posted by
Tin Can
Re: Need Guidance on Getting a Sensitometer
I just bought on eBay a matching set X-RITE 331C DENSITOMETER AND X-RITE 383 SENSITOMETER
and read both manuals for them online before buying
The manuals say it is useful for Cine and X-Ray B&W film
So 2 new toys incoming, both guaranteed to work from a high rated seller of other things, who took my offer
At least they are not huge like some of my LF adventures
Perhaps useful with my pile of old films and the still in date
Another question may be, does anybody compare frozen film to new?
I am a complete no nothing about this gear, but do enjoy trying new things
Quote:
Originally Posted by
LFLarry
Hi, yes, I did read the manual, twice actually, and I even searched the PDF as well to ensure I didn't miss anything.
I can't find anywhere in the manual where it specifies the exposure time or the illumination value of the light source for any of their units. I even went and looked at other X-Rite units and nothing there as well.
I also read the full list of specifications and nothing there as well.
If I am overlooking something, please point me to the page please.
Re: Need Guidance on Getting a Sensitometer
Quote:
Originally Posted by
Tin Can
I just bought on eBay a matching set X-RITE 331C DENSITOMETER AND X-RITE 383 SENSITOMETER
and read both manuals for them online before buying
The manuals say it is useful for Cine and X-Ray B&W film
So 2 new toys incoming, both guaranteed to work from a high rated seller of other things, who took my offer
At least they are not huge like some of my LF adventures
Perhaps useful with my pile of old films and the still in date
Another question may be, does anybody compare frozen film to new?
I am a complete no nothing about this gear, but do enjoy trying new things
Great pickup.
What I do is to test all my 'working' film/developer combinations for baseline. Then, when some "unknown to me" film or developer comes along I can compare the new stuff to the known stuff in the comfort my darkroom (with the sensitometer/densitometer) before going outside to do the in-camera tests.
https://www.largeformatphotography.i...light=shanghai
Re: Need Guidance on Getting a Sensitometer
I have been busy, but just tested the 1996 X-RITE 331C DENSITOMETER in like new condition, all documentation included with the very handy AC charger adapter Looks like original rechargeable batteries
First null or zero unit, push a button labeled NULL !
Then using the original included step wedge with OE calibration readings from 1996 in ink pen, my reading today match
Next to check if X-RITE 383 SENSITOMETER works, which is less a concern as I have a Stouffer Step wedge and could burn my my own
All made in USA
Quote:
Originally Posted by
ic-racer
Great pickup.
What I do is to test all my 'working' film/developer combinations for baseline. Then, when some "unknown to me" film or developer comes along I can compare the new stuff to the known stuff
in the comfort my darkroom (with the sensitometer/densitometer) before going outside to do the in-camera tests.
https://www.largeformatphotography.i...light=shanghai
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Re: Need Guidance on Getting a Sensitometer
Re: Need Guidance on Getting a Sensitometer
Quote:
Next to check if X-RITE 383 SENSITOMETER works, which is less a concern as I have a Stouffer Step wedge and could burn my my own
To plot the results from the sensitometer, you will need to know the values of the step wedge. Is it built-in to the 383? If so you will need to remove it to measure it with your densitometer. I had to do that with my EISCO and Wejex. The EG&G does not have a built-in step wedge. You can use any step wedge you have on the film stage.