Yet Another B/W Conversion...

By loweho
5
written 4/13/06 12:44 PM, published 4/13/06 12:44 PM
We've talked about other ways of converting to b/w but this one, to me, is probably the best, at least the most adjustable. When PS converts an rgb color photo to grayscale it takes the red, green and blue channels and mixes them in different proportions.  These proportions are stored in software and are based on how the eye responds to color.  We can do it the same way but allow us to control what percentage of each channel is used.

Open the image you want to convert. You should have the layers pallete open if not select Windows-->Layers or hit F7. Should have something like this Popup LinkFigure 1

In layer palette, select background layer and hit <Ctrl-J> to copy current layer to new layer, or drag background layer to new layer icon at bottom of layer palette. Popup LinkFigure 2  You can bypass this step and work on the background layer but I'm used to versions that didn't have adjustment layers and like to keep a virgin down there.

Select new layer, if not already selected or background layer if using it.  Click on half-light half-dark circle at bottom of layer window to open Create fill/adjustment layer menu select Channel Mixer option, or select Layer-->New Adjustment Layer-->Channel mixer. Popup LinkFigure 3

The channel mixer window will normally come up with blue set at 100%. Check the monochrome button and also the preview button.  Adjust values for individual red, green, & blue channels... good start is 45,60,15 respectively. Find a set of values that get the desired result and click ok to save the adjustment layer.  The constant slider lightens and darkens. Popup LinkFigure 4  

If desired, before closing channel mixer you can save the parameters for use next time, or save the generic start values and load them next time you open channel mixer.

You can also create another adjustment layer, a Hue/Saturation layer, and tint the b/w you just made.  Be sure to click the colorize button in the Hue/Sat window. Set the saturation level to about 10-15 for starts and play to your hearts content. Popup LinkFigure 5

You may have already known this technique, if so, sorry to take up your time, if not, then you have another thing to play with in CS2.



 
  • One thing I learned about using Channel Mixer is that the percentages need to add up to 100, as it's using percentages. It's basically asking you to tell it what percent of each channel (red, green, blue) you want to use in creating the black and white version. This is the way they teach it down at Santa Fe.

    - One size does not fit all

    Please sign in to rate.


  • loweho
    5
    Tom, you are right! And at one time I knew that I just been using it for so long I forgot. Dug out the books and checked and they do tell you to do that but not why, do you know? Obviously, it doesn't prevent you from doing that but nowhere did I see an explanation why. Thanks for the correction.

    - Fickle Finger of F8

    Please sign in to rate.


  • Wow. All of these b/w conversion tips are very informative! Is it wrong that I just hit CTRL / SHIFT / U to desaturate and then adjust contrast? ;)

    - I'm Special!

    Please sign in to rate.


  • loweho
    5
    No, code, nothing wrong with it, in fact, that and just the normal grayscale conversion are the ways I use 95% of the time. You just have more control. Not necessarily better, kinda like driving a stick over an automatic. 8o) I used to use this more but since going digital and shooting raw I usually end up with what I want by desaturating. Just something to play with.

    - Fickle Finger of F8

    Please sign in to rate.


  • loweho wrote: kinda like driving a stick over an automatic. What's an automatic?

    - I'm Special!

    Please sign in to rate.


  • excellent tip, Lowe! I'm loving this.

    - here and there

    Please sign in to rate.


  • loweho
    5
    Automatic... is when your wife drives so you can hang out the window and take pictures.

    - Fickle Finger of F8

    Please sign in to rate.


  • You need to have a "Shut-Up" button installed on the dash if you are going to do that.

    - Oh Bull!

    Please sign in to rate.


  • the best way to get black and white is to shoot in it! FILM ROCKS!

    - School is such a prison!

    Please sign in to rate.


Only registered users are allowed to post comments. Please sign in or create an account.