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  1. #1

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    Filtering for Acros 100/

    I have recently read on this forum that Acros 100 is ortho, and also that it has extended red sensitivity. Whats' the truth?

  2. #2
    fretlessdavis's Avatar
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    To me, it seems slightly more Ortho than Delta or Tmax 100. It doesn't respond to a red filter very well-- skys don't get much darker, and green foliage just goes to pure black.... even going to a stop more than recommended filter factor. Other than that, for me at least, filters behave like they would on Delta or Tmax. If I want really dramatic skys, I'll stack a polarizer and a yellow or orange.
    New-ish convert to film.
    Pentax MX for 35mm
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  3. #3

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    Is panchromatic, at least this is what the spectral curve says http://www.fujifilmusa.com/shared/bi...anAcros100.pdf

    Here is the one for TMAX 100 http://www.kodak.com/global/en/profe...4016/f4016.pdf

  4. #4
    lxdude's Avatar
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    Quote Originally Posted by kazuo View Post
    Is panchromatic, at least this is what the spectral curve says http://www.fujifilmusa.com/shared/bi...anAcros100.pdf
    Note that on that data sheet they call it orthopanchromatic.
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

  5. #5

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    Dear Chip j,

    Those two claims are contradictory. Generally, "ortho" films are only sensitive to blue and some green. Extended red sensitivity means that the film would record at least partially into the infra-red. That would be quite a problem for ortho films, particularly when you go to develop by inspection. What I think folks are getting at is that traditional films were, relatively, less sensitive to blue than red and therefore using a red filter would give you darker skies compared to the newest films (Acros/Delta/T-Max) which have a much flatter spectral sensitivity.

    Go with FP-4+ if you want that old sky look with finer grain.

    I think I added enough qualifiers in the above to wiggle out of trouble. Good luck,

    Neal Wydra

  6. #6

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    Quote Originally Posted by Neal View Post
    Dear Chip j,

    What I think folks are getting at is that traditional films were, relatively, less sensitive to blue than red and therefore using a red filter would give you darker skies compared to the newest films (Acros/Delta/T-Max) which have a much flatter spectral sensitivity.

    Go with FP-4+ if you want that old sky look with finer grain.

    I think I added enough qualifiers in the above to wiggle out of trouble. Good luck,

    Neal Wydra
    Neal, I think you are saying that the trad grain films such as FP4 will give darker skies with a red filter and yet in the case of TMax Kodak states that it is less sensitive to blue giving darker blues( closer to how the eyes sees blue) so I'd presume that with a red the TMax skies should be darker

    In the Kodak quote however I don't think it says what it is less sensitive than. Is it FP4+, HP5+, Tri-X? It just doesn't say unfortunately

    pentaxuser

  7. #7
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    Quote Originally Posted by pentaxuser View Post
    Neal, I think you are saying that the trad grain films such as FP4 will give darker skies with a red filter and yet in the case of TMax Kodak states that it is less sensitive to blue giving darker blues( closer to how the eyes sees blue) so I'd presume that with a red the TMax skies should be darker

    In the Kodak quote however I don't think it says what it is less sensitive than. Is it FP4+, HP5+, Tri-X? It just doesn't say unfortunately

    pentaxuser
    FWIW I just did a comparison with a red filter of TMY-2 and FP4+ and the negs and (scanned) images look almost identical...

    Here are the results. Sorry not printed optically but thought it might be helpful to post none the less...

    FP4+
    Click image for larger version. 

Name:	ImageUploadedByTapatalk1394304396.919495.jpg 
Views:	42 
Size:	170.9 KB 
ID:	83916
    TMY-2
    Click image for larger version. 

Name:	ImageUploadedByTapatalk1394304411.370825.jpg 
Views:	40 
Size:	172.9 KB 
ID:	83917

    Both with red filter, both in DD-X both with exact same exposure (2 stop difference obviously).
    ~Stone | "...of course, that's just my opinion. I could be wrong." ~Dennis Miller

  8. #8

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    Hi Pentaxuser,

    If a film is less sensitive to blue than red, the unfilltered sky will be slightly less dense and appear slightly darker when printed.

    At least I think that's right.

    Neal Wydra

  9. #9

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    Dear StoneNY,

    I believe you have clearly demonstrated that the vast majority the differences discussed is, for all practical purposes, picking the fly poop out of the pepper.

    Neal Wydra

  10. #10
    Fixcinater's Avatar
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    Quote Originally Posted by StoneNYC View Post
    FWIW I just did a comparison with a red filter of TMY-2 and FP4+ and the negs and (scanned) images look almost identical...

    Here are the results. Sorry not printed optically but thought it might be helpful to post none the less...

    FP4+
    Click image for larger version. 

Name:	ImageUploadedByTapatalk1394304396.919495.jpg 
Views:	42 
Size:	170.9 KB 
ID:	83916
    TMY-2
    Click image for larger version. 

Name:	ImageUploadedByTapatalk1394304411.370825.jpg 
Views:	40 
Size:	172.9 KB 
ID:	83917

    Both with red filter, both in DD-X both with exact same exposure (2 stop difference obviously).
    Thanks for posting this.

    Just to satisfy curiosity, did you set contrast (or: black and white points) equal to each other or to taste individually? The only "real" difference I see is the TMY-2 frame going a bit darker in the deep shadows, hence my question.

    Thanks again for the comparison.

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