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  1. #11
    LJH
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    Quote Originally Posted by Regular Rod View Post

    That would be 5 seconds
    . You simply look across to the numbers on the right hand side. You can make the chart easier to use by printing it off with a grid.
    I get it at 4 seconds. Or 6. Or 5, as you wrote, depending on where I decide 2 seconds lies and where the intersection point is. Hardly accurate. At best, it is an indicative graph.



    Quote Originally Posted by Regular Rod View Post
    What did you do when you were finding out that EKTAR 100 was pretty forgiving?
    I avoided rubbish graphs and shot with it. I also looked at dark locations shot on Ektar Google Images and explored the Shooters' descriptions.

  2. #12
    Regular Rod's Avatar
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    Quote Originally Posted by LJH View Post
    I get it at 4 seconds. Or 6. Or 5, as you wrote, depending on where I decide 2 seconds lies and where the intersection point is. Hardly accurate. At best, it is an indicative graph.





    I avoided rubbish graphs and shot with it. I also looked at dark locations shot on Ektar Google Images and explored the Shooters' descriptions.
    It is easier to read the graph if you print it with a grid. I can send you a file if you like.

    I like the idea of looking on Google at images and seeking the information from there.

    RR

  3. #13
    LJH
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    Thanks for the offer; I've moved on to an App that gives me Reciprociy, though, so shouldn't need it.

    Speaking of that App, it has Ektar on it, so I'll run a spreadsheet of its data, convert to a graph and PM you with it if you'd like?

  4. #14
    Roger Cole's Avatar
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    Quote Originally Posted by LJH View Post
    I get it at 4 seconds. Or 6. Or 5, as you wrote, depending on where I decide 2 seconds lies and where the intersection point is. Hardly accurate. At best, it is an indicative graph.
    The difference between 5 versus 4 or 6 seconds is only 20%. Insignificant especially with color neg. Always err on the side of more exposure with color nef so give it 6 and don't worry about it.

  5. #15
    LJH
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    Quote Originally Posted by Roger Cole View Post
    The difference between 5 versus 4 or 6 seconds is only 20%. Insignificant especially with color neg. Always err on the side of more exposure with color nef so give it 6 and don't worry about it.
    It's for HP5+.

    And it is more than 20%, as you have reciprocity failure on reciprocity failure.

    But my point was, it is not an accurate graph, particularly for shorter exposures.

  6. #16

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    I like long exposure photography and I have practice it quite long. I have to say that in my experience Ilford films have generally much worse reciprocity failure than any Kodak emulsion I have used. I am not a big fan of Ektar, to be honest I don´t like it at all, but I expect Ilford table to give overexposed results, when used with for it. The best way is to make tests and check the exposure and the color rendition. It seems like Ektar tends to shift more to cyan when used for very long exposures.

    Here is a link for an old APUG thread:

    http://www.apug.org/forums/forum40/5...exposures.html

  7. #17
    Regular Rod's Avatar
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    Quote Originally Posted by LJH View Post
    Thanks for the offer; I've moved on to an App that gives me Reciprociy, though, so shouldn't need it.

    Speaking of that App, it has Ektar on it, so I'll run a spreadsheet of its data, convert to a graph and PM you with it if you'd like?

    What's the App. called? That could be the answer...

    RR

  8. #18
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    Quote Originally Posted by LJH View Post
    It's for HP5+.

    And it is more than 20%, as you have reciprocity failure on reciprocity failure.

    But my point was, it is not an accurate graph, particularly for shorter exposures.
    Well ok - lost that in the thread I guess. But no matter, I'd bet (a small amount) of money that one could barely tell the difference visually between 4, 5 and 6 second exposures.

  9. #19

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    One of the problems with nite photog is that the film speed depends a lot on the light source. You get all kinds of artificial sources potentially mixed into the scene. Then if there's is corrective filtration in play,that has to be factored in. So maybe Kodak just decided to play it safe and say nothing. But if I get around to experimenting myself, I'd probably follow a game plan similar to that already posted.

  10. #20
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    Quote Originally Posted by Regular Rod View Post
    What's the App. called? That could be the answer...

    RR
    Reciprocity Timer.

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