Channel mixer to B&W

[Grev]

I don't know how to do this, well not properly anyway, is there a rough guide on how to do this? And is this just mixing in RGB or in CMYK or other colour spaces (which I highly doubt)?

[Yi-P]

There are so many ways in turning things to BW.

Matt K. uses a method in CMYK channel and isolating one of the channel through extraction method. I dont really use this one, so I'll let him explain this if he drops by.


In channel mixing option, open your original image.

Create a new adjustment layer for "channel mixer".

Check/tick "monochrome" option at the bottom of the dialogue box. You will now see your image turn B&W instantly and your GRB channel turns into 'grey' channel.

Tune your Red, Green & Blue channels up and down so you get a good 'feel' about the output of your image.

As a general rule (just as a guide) all channels must add up to 100% in order to make back to your original exposure.
Say eg.
R: 60% G: 20% B: 20%
R: 40% G: -20% B: 80%
R: 10% G: 50% B: 40%

Either way, you try out the output for your image to the most suitable style you are looking for. The above is just an example on how to work out the 100% total, not an actual live sample.

Later on, add another adjustment layer for "curves" adjust your shadow and highlight curves, you will then now have a much more punchy B&W feel. You may add some noise on top if you feel like it.

[Grev]

Thanks Yip, I knew how to do it and stuff, just don't know if there are any holy grail values, that's all.

Well I found that in portraits, too much blue will make you look like a zombie, and I have found ambiguous but good results having more red or greens. So yeah...

http://www.deviantart.com/deviation/48154831/ It's myself and quite a few curves were done on it, but the main thing is that in the normal greyscale conversion, my lips were lighter than when I did the channel mixing conversion.

Also it's suppose to be fun so I use curves and levels like 4 or 5 times.

[Yi-P]

I like to blow things to near extremes with B&W:

like http://www.deviantart.com/deviation/47409054

Or something more of a balanced if that is what you looking after:

http://www.deviantart.com/deviation/48032758/

From memory, both were turned down into a ratio in R80% G:40%: and B:-20%

Or R70% G15% B15...

Then pull up the curves and blow things up

[Grev]

Hey, we should watch each other!

And yes, I quite like the tones on them, the apparent heavy contrast really works in certain situations.

I like that you've shown the figures, gives a good reference point.

[Antsl]

I have been getting good results by using the Hue/Saturation control. Have the image open as an RGB file... create an adjustment layer for the Hue / Saturation control and then Slide the saturation down to nothing until the image goes to black and white.

Now before you close the dialouge box, you will notice the option box marked MASTER.... this also has red, green, blue, magenta, yellow and cyan as colour options to manipulate. Choose the colour that represents the tones you want to manipulate in the image and then adjust the Lightness slider to adjust those tones. When you are happy with the look of the image click OK.

This is a lot simpler than the channel mixer option and yet still lets you manipuate the individual tones within the image. I have just been converting some colour scans to black and white for a magazine using this technique and it made things rather straightforward.

Hope this is a help. Ants

[Grev]

Thanks! The more ways to do things the merrier!