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  1. #1

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    Color film less sharp than slides / B&W?

    When I shoot films, I have been mainly shooting B&W and slides. I shoot mainly in XPan, 120 and 4x5 format. Haven't shot straight 35mm for probably 8 years.

    I have a Jobo and rotary process all my films. I then scan using a LS-9000 (XPan or 6x7) or V700 (617 or 4x5)

    Last few months, I tried color films, the XPan and 120 seem not to as sharp as the slides and B&W. The negs look pretty good exposure wise, and I am precise with water temperature and timing. I use a Kodal color thermometer and not the Jobo builtin temperature gauge. For testing purpose, I even have a lab processed one of the rolls and the results are similar.

    So are color films (Portra 400) inherently less sharp than slide film or may be I am comparing apples to oranges or my process still need more tweaking?

    I use the Arista C41 for color films, divided Pyrocat for B&W, and Tetenal E-6 for slides.

    Thanks!

  2. #2
    Nikanon's Avatar
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    Most likely it is your scanner on the 120 issue with how it is mounted. Your film really has to be dead flat to scan well, and 120 is a larger surface area and therefore has a better chance of not being totally planar during the scan. I warm up my negatives and then stick them under a book or other totally flat surface with weight for a whole day.

    Color films are however actually less sharp than their black and white counterparts. The line pair resolution of color films is much less, likely due to their being made up of coupled dyes and the orange mask that is placed over negative films.

    Color negative and positive films are pretty similar in their characteristics of resolution, but it really depends on which film you are talking about.

    Remember, "sharpness" is meant to be the perceived contrast of edges of fine details throughout the image. Monochromatic silver grains can render higher resolutions than multicolored dye any day.

  3. #3
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    Quote Originally Posted by Nikanon View Post
    Color films are however actually less sharp than their black and white counterparts. The line pair resolution of color films is much less, likely due to their being made up of coupled dyes and the orange mask that is placed over negative films.
    Got data to back that up?
    Mark Barendt, Beaverton, OR

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

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    Quote Originally Posted by Nikanon View Post

    Color films are however actually less sharp than their black and white counterparts. The line pair resolution of color films is much less, likely due to their being made up of coupled dyes and the orange mask that is placed over negative films.
    In terms of line pairs per mm, it's not possible to say 'black and white is more than colour' any more than you can say 'Canon DSLRs have higher resolution than Nikon', you'd really have to come up with some specific examples.

  5. #5
    Nikanon's Avatar
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    Quote Originally Posted by markbarendt View Post
    Got data to back that up?

    Here is the PDF for Ektachrome 100, but any Data sheet that gives MTF will tell the same story. The Lp/mm here is about 30 at 50% contrast:
    http://www.kodak.com/global/en/profe.../e113/e113.pdf

    Here's the Data sheet for portra 400, where the MTF 50 of the longest wavelength red, is also about 30-40 Lp/mm:http://www.kodak.com/global/en/profe...4050/e4050.pdf

    Here's Kodak Tri-x 400, a fairly lower resolution film among black and white films, it can still resolve about 50lp/mm at MTF 50: http://www.kodak.com/global/en/profe...4017/f4017.pdf

    Of course there are other factors such as development and what lens you ate using, but otherwise resolution is essentially a measure of perceived sharpness at MTF50.

    Don't expect the same fine details from even Kodachrome 64 slides as from say, Ilford FP4.

    The image size will also affect perceived sharpness as the eye (or your computer screen) can only resolve so many line pairs at a specified distance. At a small enough size the same lens imaging on color and black and white films the same scene, the images will look indistinguishable in their "sharpness".

    T-Max 400 resolves about 75 Lp/mm, while t-max
    100 resolves about 120, and even the grainy P3200 can resolve about 75 Lp/mm at MTF 50: http://www.kodak.com/global/en/profe...4016/f4016.pdf
    Last edited by Nikanon; 10-03-2013 at 06:22 AM. Click to view previous post history.

  6. #6
    polyglot's Avatar
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    As an overgeneralisation, yes it is true that most C41 films are softer than (some) B&W films and chromes.

    Practically nothing is less grainy than Acros or TMX, and nothing in ISO400 is as good as TMY2, so there's that. But then, nothing is coarser at a given ISO than Fomapan, so it depends which films you are comparing.

    In my experience, Ektar is about as sharp and smooth as Velvia, maybe even better and RVP50 is the smoothest reversal film on the market, so the "best" C41 is smoother than the smoothest chrome. But then, the cheaper (Reala) and older (400VC) C41 films are very coarse compared to chromes of similar vintage (RDP, RXP), whereas the newer CN emulsions (New Portra in 160 and 400) are very fine. P400 is better than Reala and RXP but can't match RDP. P160 is probably as good as RDP.

    So you can cut it whichever way you like really. Quantitative comparisons are also very difficult because MTF50 on the film means an entirely different thing on a negative as a positive because of the contrast gain in the printing process. A C41 neg that will achieve the same MTF50 in a print will have a lower MTF50 in the negative, which means comparing it to the MTF off a chrome is unreasonable. But then, chromes can have a higher Dmax, which means they naturally have the opportunity to get better acutance than any reflected print can achieve.

    Just shoot what you like. If you want to try a colour neg that looks like a chrome, get some Ektar and print it optically. Hint: Ektar is comparatively cheap in 4x5"

  7. #7
    Nikanon's Avatar
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    Knowing resolution and how it affects the image can be useful, but for shooting 35mm negatives or slides, or even 120, I would imagine its more about the color. There's less you can do to control "sharpness" anyway with your color films. If
    You want fine details, larger format, if you want relatively small prints, 35mm should be fine.

  8. #8
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    I am in the process of printing (hybrid) some 35mm slides (KR64 and Fuji Sensia). On screen the scans differ a lot in color (I prefer much more film) compared to digital (which I use in a more careless way, BTW; Only JPG). For me a 8x12" print is quite big at the moment and medium speed film should fulfill nicely. Some grain doesn't hurt and it can help in acutance.
    Slide needs a careful approach to (hybrid) printing, as I found it loses "crunch" (transmittive to reflective media).

    I've gotten some Portra 400 to try and want to get a bit of ektar for next spring. As of products, Portra 400 has lots of praise for what it delivers, being ISO 400. I wouldn't be surprised if it's grain wise on par or slightly grainier than Kodachrome 64, at 8x12".

  9. #9

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    Quote Originally Posted by Nikanon View Post
    T-Max 400 resolves about 75 Lp/mm, while t-max
    100 resolves about 120, and even the grainy P3200 can resolve about 75 Lp/mm at MTF 50: http://www.kodak.com/global/en/profe...4016/f4016.pdf
    I may have misunderstood the science here(quite likely) but the source you quote seems to suggest that P3200 has a resolution the same as TMax400 and is better than the colour film you give as an example.

    I am particularly surprised that P3200 matches Tmax400 and beats I think it was Portra you mention

    Good as P3200 is for a fast film my limited experience with it suggests to me that even at a 5x7 size print a P3200 neg doesn't match a TMax 400 neg

    What's others' experience of this?

    pentaxuser

  10. #10
    polyglot's Avatar
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    Quote Originally Posted by pentaxuser View Post
    I may have misunderstood the science here(quite likely) but the source you quote seems to suggest that P3200 has a resolution the same as TMax400 and is better than the colour film you give as an example.

    I am particularly surprised that P3200 matches Tmax400 and beats I think it was Portra you mention

    Good as P3200 is for a fast film my limited experience with it suggests to me that even at a 5x7 size print a P3200 neg doesn't match a TMax 400 neg

    What's others' experience of this?

    pentaxuser
    It's why you don't compare numbers from separate sources, because there are so many differing ways of defining the measurements. Note also that resolution and graininess are not that well-correlated.

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