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Thread: Need Guidance on Getting a Sensitometer

  1. #31
    ic-racer's Avatar
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    Re: Need Guidance on Getting a Sensitometer

    Quote Originally Posted by LFLarry View Post
    Hi, I want to make sure I am clear on a point that you made in the first link below.

    Are you saying that the blue and green LED sensitometers that are readily available today which were designed for Radiographic work I believe are sufficient for testing B&W 35mm roll films for the range of sensitometry tests as outlined in Kodak's "Basic Photographic Sensitometry Workbook"?
    LED sensitometers work fine for comparative testing most black and white panchromatic films. Analogy is a 'balance' where you have to place objects on both dishes to compare things.

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  2. #32

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    Re: Need Guidance on Getting a Sensitometer

    Just watched it Greg. I gave it a thumbs up and commented and posted a question for you too (Stealth Van Life is my YouTube handle).


    Quote Originally Posted by Greg Davis View Post
    New video in the series, Contrast Index: https://youtu.be/TwTymRBedz4

  3. #33

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    Re: Need Guidance on Getting a Sensitometer

    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?


    Quote Originally Posted by Tin Can View Post
    I have no idea if these are worth buying, but there are 50 FS

    I think they were used for Mammogram X-Ray which was the last of the analog uses in NA

    https://www.ebay.com/sch/i.html?_fro...R+SENSITOMETER

  4. #34

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    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 View Post
    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.

  5. #35

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    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 View Post
    LED sensitometers work fine for comparative testing most black and white panchromatic films. Analogy is a 'balance' where you have to place objects on both dishes to compare things.

    Click image for larger version. 

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ID:	207535
    Click image for larger version. 

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Views:	7 
Size:	29.0 KB 
ID:	207536

    Click image for larger version. 

Name:	film spectral sensitivity.png 
Views:	8 
Size:	84.8 KB 
ID:	207537

  6. #36
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    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 View Post
    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?
    2022

  7. #37
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    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.

  8. #38

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    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 View Post
    Did you read the manual I posted?

    Here it is again


    https://www.xritephoto.com/documents..._Manual_en.pdf

  9. #39
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    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 View Post
    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.
    2022

  10. #40
    ic-racer's Avatar
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    Re: Need Guidance on Getting a Sensitometer

    Quote Originally Posted by Tin Can View Post
    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

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