Black and White Conversions - DPChallenge Forums

Nikon AF Nikkor 50mm f/1.8D

08/15/2004 02:42:19 PM · #5

I found the same results John,If I want a black and white image, I do all the tonal and contrast things in colour then convert and tweak it. Might not be the correct way but it works for me.
If I am still not happy I resort to duotone.

David.C

08/15/2004 02:52:37 PM · #6

Cool -- I'm not the only one that is not finding it all that useful.

Don't know if this will be of benefit, but I was under the impression it served a similar purpose to using colored filters in B&W photography -- with a lot more control over which colors are accented. I had set it aside as something much further along the learning curve than I am, and I needed to concentrate on other things.

Although I generally desaturate an image in an adjustment layer, so I can apply adjustments and filters to the channels individually if I feel the need. So maybe what I am doing isn't all that different after all.

David

dwoolridge

08/15/2004 03:10:12 PM · #7

I think the CM method simply provides more in-edit control (as an adjustment layer) and a greater ability to control constrast/tone relationships without the necessity of other tools (contrast/levels/etc). On the other hand, using CM does not mean that those other tools won't still come in handy to further refine the b/w conversion.

You can get a grayscale equivalent by using a (R,G,B) = (30,59,11) CM recipe. That would be a starting point for someone who wants to explore the benefits of using CM. I'm currently playing with the dual HS layer approach, but I still use CM most of the time. I never use grayscale because it throws a bit of a wrench into a color managed workflow.

Message edited by author 2004-08-15 15:10:30.

Pedro

Nikon D200

Nikon AF Zoom-Nikkor 70-200mm f/2.8 VR DG IF-ED

08/15/2004 03:10:56 PM · #8

Jim, I find it a whole lot more useful on landscapes and still life images than i do on people. it's particularly good when one channel dominates the image (like a really red/orange fall scene, or green trees behind green grass etc). with people - especially brown eyed people - it does weird stuff to their eyes.

P

@david - looks like you've been playing in my backyard ;)

Message edited by author 2004-08-15 15:13:01.

dustin03

Canon EOS-20D

Sigma 24-70mm f/2.8 EX DG Macro for Canon

08/15/2004 03:20:07 PM · #9

John, Count me in...I really have never had any luck for the main use of the "channel mixer".....maybe for shifting colors on other photos than B/W's...even with useing the presets for b/w in channel mixer...I have to agree about converting to Grayscale and then add tones (if will) and then adjust the levels ect....From what I have found that this is the best way for now....Sorry, to have not any ideas how to make channel mixer better for b/w's....I think that if you keep asking around, you'd find out more....Btw, I'm looking forward to your new Website, "duotones.org." Waiting to add to the collections....it's a great idea you have there!

Blackdog

Canon EOS-20D

08/15/2004 03:20:14 PM · #10

Hi, I think using the channel mixer does give more control over the image if you want to create a particular effect. Obviously it depends very much on the subject and the main colours in the start image. For instance the blue channel can give really high contrast effects and will enhance things like freckles and wrinkles in portraits.

With portraits of older people it can really emphasise their age and skin condition.

Nikon AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II

08/15/2004 06:41:39 PM · #11

Firstly it is very image dependant. What it allows you to do is change the amount of each channel in the final image. Image-Greyscale uses a set % of each channel. Channel mixer lets you do it yourself and vary the amount. So we are to the point of 'more control' again.

Usually, I start off by duplicating the image, going in to the menu on the channel palette and separating the various channels out - you can then see the usually stark difference between the red, green and blue channels. This is particularly true for white/light skin tones - the red channel is almost porcelin smooth, the blue channel has all the freckles, spots and skin marks.

From there, I get a good idea of how much of which channel I want to use - for an 'even' conversion, I use ratios so that they add up to 100%. For a high contrast effect, I'll mix over 100%, to about 150% or so.

It can also be interesting to subtract channels, using -% values.

But right at the heart of this - it really depends on the type of scene you've shot, and if you want to vary the tonal relationships between the colours or not - e.g., a sky shot were you could change it from an almost light sky to an almost completely dark sky, as you vary the blue component.

As a final aside, I never, never, ever use the constant adjuster. It is roughly equivalently useless as the brightness/ contrast adjustments.

Message edited by author 2004-08-15 18:42:25.

dacrazyrn

Nikon D300

08/16/2004 09:10:25 AM · #12

I still love the non destructiveness and control of DigiDan's Conversion the best.

BobsterLobster

Fujifilm FinePix S3 Pro

Nikon AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II

08/16/2004 09:25:23 AM · #13

I'm sure someone will correct me if I'm wrong, but I am under the impression that using the channel mixer for b&w conversion keeps more tonal detail in the image. A black and white image contains 256 discrete tonal levels from black through to white. A colour one has 256*256*256 different levels, and using the channel mixer allows you to keep that information when converting. You can see that this is important when carrying out curves modifications, which can result in a posterised effect if the 256 levels are stretched out too far.

garlic

Canon EOS-10D

Sigma 15-30mm f/3.5-4.5 EX Aspherical DG DF for Canon

08/16/2004 09:46:39 AM · #14

Have been experimenting a bit with this method to make high contrast B&WÂ´s:

1. Enhance - Adjust Color - Remove Color
2. Enhance - Adjust Brightness/Contrast - Levels
3. Layers - Duplicate layer
4. Image - Adjustments - Threshold (For high key images lower threshold very much but less for normal and very litle for low key)
5. Blend the layers with "overlay" and find out what "opacity" suits best (I often but it to 50-70%).

This method doesnt work for all images but the results are sometimes sharp and high contrasted images.

Just recently started to experiment with this. Maybe post something here soon.

soup

Canon EOS-30D

Canon EF 70-200mm f/2.8L IS USM

08/16/2004 09:47:16 AM · #15

that is what i use almost solely. i like the results, and its a one slider deal. i edit the lower adjustment layers hue.

Originally posted by dacrazyrn:

I still love the non destructiveness and control of DigiDan's Conversion the best.

and i think its what dwoolridge is doing as well with his exploration of hue/saturation adjustment layers - just a key press to create those adjustment layers with digidaans action.

Originally posted by dwoolridge:

I'm currently playing with the dual HS layer approach, but I still use CM most of the time. I never use grayscale because it throws a bit of a wrench into a color managed workflow.

Message edited by author 2004-08-16 09:47:48.

EddyG

Canon EOS-1D Mark II

08/16/2004 09:53:40 AM · #16

Originally posted by dacrazyrn:

I still love the non destructiveness and control of DigiDan's Conversion the best.

I also like this dual-adjustment-layer approach.

jonpink

Panasonic Lumix DMC-LX2

08/16/2004 09:58:01 AM · #17

I always just use image >> desaturate.

Think I will test some of those advanced methods out!!

Message edited by author 2004-08-16 10:00:43.

Chiqui

Olympus OM-D E-M1 Mark II

Olympus 12-40mm f/2.8 Pro

08/16/2004 09:58:40 AM · #18

the channel mixer conversion has worked very few times for me. Most of the time it just turns normal pictures into incredibly noisy ones. Perhaps I'm doing something wrong, but it just doesn't work for me. I'd like to understand why it does this.

June

08/16/2004 10:16:33 AM · #19

Originally posted by chiqui74:

Use less of the blue channel, more of the red & green channels, and make sure the %'s add up to around 100%. Don't use the constant adjuster, have monochrome checked.

The blue channel is usually far and away the noisiest part of the image, particularly on portraits.

08/16/2004 10:19:03 AM · #20

Originally posted by jmsetzler:

Can someone pass me some tips on why I should use the channel mixer? How will it benefit me?

I knew I had this somewhere. This is something I wrote a couple of years ago, but the pictures at least illustrate the reasons why I find the channel mixer potentially useful.

B&W workflow

Brent_Ward

Canon EOS-5D

Canon EF 85mm f/1.2L USM

08/16/2004 10:20:26 AM · #21

The channel mixer simulates a B&W darkroom. By using red, green, or red filters in the darkroom you can increase the contrast of the print differently. Use the opposite color to bring out the tone you aiming for.

dsidwell

Canon EOS-5D

Canon EF 28-135mm f/3.5-5.6 IS USM

08/16/2004 10:30:40 AM · #22

I don't always use the channel mixer, but even when I do, I look at the photo in each RGB channel first, to see what might work best in the channel mixer. For example, I'll look at the blue channel, green channel and red channel to see how the photo looks.

Sometimes, I'll just switch to Lab Color and simply convert to grayscale using the Lightness channel. Sometimes, in RGB, I'll simply convert to grayscale using one of those channels.

In this image, I used the channel mixer after seeing the effects in each of the different channels. I finally selected the red channel, which was like putting a red or orange filter on the sky, making it darker.:

In this photo, however, I used the green channel, which kept everything lighter, because there are no contrasting colors with green in the photo:

The red channel is great for caucassian skin in darker situations, since skin has lots of red tones, so I used the red channel for this one:

Here's one where I used the Lightness channel and simply converted to grayscale (and deleted the other channels):

So the channel mixer, as MeThos indicates, can be kind of like using filters. I check all methods out until I find the one that suits the subject best. But more often than not, now, I'll PLAN on using a certain channel, so I can do more special work in-camera, like put a blue or yellow cast over the photo so when I convert to b/w I'll have a certain effect.

(edited for grammar; added another sentence)

Message edited by author 2004-08-16 10:33:43.

GoodEnd

Canon EOS-350D Rebel XT

08/16/2004 11:20:35 AM · #23

If you are a color photographer, and had used color film or get in direct in digital, you really donÂ´t saw any great advantage using Channel Mixer method.

It method has the particular benefit simulating the color filters and filters stacking used in the old B&W Film pictures. I really agree that is more dificult to understand this method if you donÂ´t do it phisically before. I finally understand it by viewing a lot of photos in B&W at art shows. The diference between this and the simple grayscale conversion is the power of control over each channel. That is only usefull if you really knows what you whant to get.