CMYK Black & White Conversion Technique?

Discussion in 'Digital Darkroom' started by addam_tron, Apr 27, 2008.

  1. So I've been experimenting with a bunch of different photoshop RGB to CMYK black
    and white conversion techniques and can't seem to find one that creates a pure
    black and white image. Most of them leave the image tinted a slight brown,
    yellow tone. I'm really trying hard to resist just converting to greyscale, then
    converting to cmyk. I'm working on creating a black and white photo book for

    Anyone got any favorite conversion techniques?
  2. I'm no Photoshop pro but I came across this and it works for me.
    PSD Channel mixer way of converting color to b/w
    open image,
    go to layers - open channel mixer,
    click on mono,
    Starting Numbers,
    Red 40
    Green 100
    Blue -10
    Constant -10,
    Adjust as needed
  3. Do you have Photoshop Cs3/ AHve yo usimply tried the convert RGB to Black and White
    options? it is loaded with about 10 presets which you can fine tune to your hearts content.
  4. hmmm... i'm not sure i understand... are you looking at a print? is the printer capable of printing black and white using only gray or is it a CMYK machine, period? and even then, is it a wal-mart inkjet or a barn-size heidelberg? printer profile will always translate

    have you tried black-grey duotone? in my experience the result is much more about the right curve than about filter dials... but then again, i am no expert
  5. 1_why do you need CMYK to start?

    2_If its for high end magazine or high end commercial printing like a art book, i use to create my BW using 2 or 3 ink, the method then call duotone or tritone. You could get *good* bw from a CMYK, but not neutral as the mention method.

    Theres much more than RGB > Grayscale > CMYK, doing this will get you a bad BW to start with. You will be better using instead in RGB the Channel mixer or the BW tool in CS3, getting a amazing BW first, flatten this original then converting to CMYK.

    but im really cuious as for why you would need a BW CMYK to start with ?
  6. You first need to figure out what CMYK process you're aiming for! Then you could alter the
    GCR to get far more black in lieu of CMY (high GCR) but you're playing with fire here until you
    define the CMYK print process, get a profile built for it, then figure out the appropriate black

    And CMYK isn't Grayscale. Is the book using a four or 1 (or more) color process?
  7. I am producing a commercial grade black and white photography book. I have about 200 images to convert, so I'm hoping there is a good way to do a lot of images. It does need to be CMYK for the printer.
  8. I'd do the B&W conversions from the RGB originals and then convert that black and White RGB
    file to CMYK if the people doing the book can supply you with a decent profile and you can
    provide match prints.
  9. I use channel mixer, adjust accordingley for the image then overlay the individual RGB channels with black layer mask. I then "paint in" where I think the image will benifit from the individual channels as I feel a straight channel mix is a compromise as each colour has a differant tone and this is brought out in the method. I then, dependent on the image, use a gradiant map (Black-white / dither) i then alter the midpoint to alter the contrast / tones. I find this better in monos to a levels or curves adjustment.

    I'm looking at developing my mono work and would be interested in any comments on toning.

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