to shoot in B&W or colour?

Discussion in 'Beyond the Basics' started by elliotjnewman, Feb 3, 2005.

  1. elliotjnewman

    elliotjnewman TPF Noob!

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    If the negs are scanned to digital - is there any need to shoot in B&W? I mean, will a desaturated colour scan look different to a B&W scan?
     
  2. Rob

    Rob TPF Noob!

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    The difference between a Photoshop B&W image and a hand-printed darkroom B&W enlargement is apparant when looking at the two side by side, but I can't really describe the difference technically. The Blacks will be blacker and the Whites will be whiter as slight difference in colour balance can alter greys visibly.

    Personally, I don't shoot B&W film unless I really want to capture a B&W subject at it's best. I consider colour neg scan / PS mode greyscale to be of ample quality and I do it more often - mainly cos I'm too impatient to wait for E6 and I use C41 hourly processing!

    In fact, thinking about it, I would say that Fuji Velvia 50 or Kodak Portra 160NC converted to B&W post-scan will be a "better" image than a C41 process B&W. E6 however is probably always going to win the race as the natural grainy finish of most of the good B&W films by people like Ilford is very hard to beat.

    Have I helped, or confused? I suspect probably confused!!
     
  3. elliotjnewman

    elliotjnewman TPF Noob!

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    no no, you have helped, but Im interested in when you said that the blacks will be blacker and the whites whiter - why? surely this all depends on the output of the image? and if the Pshop file looks less rich then just pump up the levels?

    What is the difference in E6 and C41?
     
  4. santino

    santino TPF Noob!

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    E6 is slide developing, C-41 color negs (something like CN16)
     
  5. Rob

    Rob TPF Noob!

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    Crikey, you do ask a difficult simple question!!

    Right - imagine how a computer thinks with an 8-bit RGB image: Red, Green and Blue are varying in intensity between 0 and 255. Black and White film is measuring only one linear scale - light intensity between dark and bright.

    Green grass, just so happens to be 28% grey (which is half way between white and black), so does the back of a Japanese person's hand! Both these things are used by Fuji to calibrate their film. US calibration generally favours red, hence Kodak's film rep for producing red-intense images.

    Let's say you're taking the sky, which happens to be perfectly intensely blue with no other colour whatsoever. B&W film in a camera will theoretically make that about 33% grey intensity, BUT actually more like 28% in real life as it is balanced on green grass, back of hand etc.

    With computers, Red = 0, Green = 0, Blue = 255 for this example. This will give you a B&W image intensity which is R+G+B / 765 = 255/765... which is 33% grey.

    Therefore, there is a 5% error margin because of manufacturer's calibration to "normal" photography.

    This is a vastly over-simplified example, but there is a variation in the intensity, mainly because the computer's algorithm is "correct" and the film manufacturer's calibration is "optimised" to normal circumstances.

    I invite everyone to shoot me down in flames for that, but that is what I was taught, and it seems to hold true.
     
  6. Rob

    Rob TPF Noob!

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    If you're displaying only on your screen and the web, sure. However, when you pump up the levels in PS... (I use -5% bright +5% cont for the web) You may find with B&W it upsets the delicate balance when printing. Use with caution if you're printing it out.
     
  7. elliotjnewman

    elliotjnewman TPF Noob!

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    robhesketh - thanks for the detailed explanation. So would the process be any different in 16bit? instead of 8bit?
     

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