Black and white conversion options

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Water drops. Nikon D3100, 60/2.8 G.

I’ve gotten a lot of emails after the Leica X2 and M-Monochrom reviews asking about B&W conversion and processing; I guess the M-Monochrom announcement had a knock on effect on the way people started seeing things. It doesn’t make color cameras redundant for B&W work, though.

Let’s start by demystifying two things.

1. Certain cameras have certain particular B&W characteristics. True, but only if you use JPEG. If you are shooting RAW, they provide different starting points – this is from a tonal response point of view – but ultimately you can get a consistent look regardless of the camera. I know, because I do this all the time.

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Singapore. Fuji X100

2. There are benefits to a monochrome-only camera. True. The Bayer filter and subsequent conversion is an interpolation of neighboring pixel image data to extract color information; luminance information is lifted from the photosite. Any sort of interpolation will reduce tonal accuracy and increase noise, because the luminance value you’ve got is now an approximation instead of a true value. However, it’s fairly easy to see that whilst there are benefits to shooting monochrome-only, you can actually convert a color RAW file into a monochrome one, and lower the perceived amount of noise – though not to as low a level as a monochrome-only camera. If you have a poor interpolation method, then the luminance values can be affected too – once again, increasing the perception of pixel-level image noise in a color image. Bottom line: yes, lower noise, and yes, better detail.

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Trees. Leica M9-P, 21/3.4 ASPH.

Also one of the images available in my print offer.

However, what you lose from a monochrome-camera is the ability to do control the relative luminance level of individual color channels. Why is this important? Suppose your color scene has a relatively small range of background tonal values, but your subject is a very different color. Its luminance may be the same as the background, but it stands out because of the difference in color. As we concluded in a previous article, this kind of image is a very bad candidate for B&W conversion off the bat, because you’d land up with something very flat-looking. (Real life translation: running out and buying an M-Monochrom isn’t going to solve your B&W conversion woes, but it will give you an interesting starting base – especially when it comes to noise and dynamic range. Those of you who don’t mind doing a bit of work, hold on to your normal cameras. And in fact, these techniques apply to the M-Monochrom too.)

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Noryn Aziz in the spotlight. Nikon D700, 24-70/2.8

Actually, if you’re prepared to do some work, this not necessarily the case. It’s still possible to separate the subject from the background on the basis of luminance only; you just need to work a bit harder. You’ve even got a few options here. Park that thought for a moment, we have to introduce the basics of B&W conversion first.

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Shadows. Leica M8, Voigtlander 50/1.1

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A sample image for the purposes of demonstration for this article. This is the original file, converted from RAW, with all of the sliders set to zero. Olympus OM-D, 45/1.8.

The simplest method is to desaturate. All this does is throw out color information, and leave luminance information only. You are then free to do whatever you wish to complete processing of the file. After much investigation and experimentation, this is actually the method I use, coupled with another trick or two. Desaturation can be done in ACR (saturation slider, first tab) or in Photoshop (Hue/Saturation tool, then desaturate the master)

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Straight desaturation. Note overall lack of contrast.

Slightly more complicated is the gradient map. You can use the standard linear black to white transition (press D in photoshop first, then add a new gradient map adjustment layer) – which gives very similar, but not quite the same, results as desaturation. Gradient maps with a straight gradient tend to be a bit more contrasty than desaturation. If you want to experiment a bit, it’s actually possible to put in intermediate control points into the gradient and bias it towards a high key (mostly white, black fades out faster) or low key (black stays for longer) look. What actually works here will depend on your image, however, so be prepared to do some fiddling. The good news is that if you use a new adjustment layer, the gradient is easily modifiable without having to redo your entire conversion.

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Gradient map, linear gradient. Note increased contrast over the straight desaturation.

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Gradient map, low key gradient (mostly black)

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Gradient map, high key gradient (mostly white)

Finally, we’ve got the channel mixer. Best used on the RAW file in ACR, this lets you decide how much of each individual color channel goes into making the final image. Note that the tool only uses the luminance components of each channel, and it’s additive; this means that color (and perceptual color) information is discarded. To make things even more complicated, there’s a separate B&W conversion adjustment layer in Photoshop itself that effectively does the same thing as the ACR conversion, but it only has six channels for you to play with instead of the eight in ACR.

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Channel mixer via ACR, decreased reds; note how the subject (in this case, predominantly in the yellow channel) stands out more from the background.

Remember the conundrum of how to isolate a different colored, but similarly luminous, subject from the background from earlier? The solution to this is the channel mixer. You can increase the luminance of the primary color of your subject, and decrease that of the predominant background color; the converse also works. The problem comes when you’ve got a mixture of colors in both subject and background, and some of those are common colors. (Don’t get carried away though: remember that some images just don’t work in black and white).

This isn’t, the entire toolkit, of course. You’ll find that after this kind of conversion, things look rather flat. That’s because a lot of how the human eye perceives contrast and separation is dependent on differences in hue; obviously we have removed that, so we have to artificially put it back in again. Two of Photoshop’s tools will be your best friends here: the dodge and burn brush, and the curves tool. Understand how both of these things work, what the dos and don’ts are, and you can work magic with any B&W conversion. A tablet is also extremely helpful for these things, as it gives you precision control and feathering over your brush application. It lets you avoid hard edges, odd abrupt transitions, and permits highly precise editing.

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Desaturation with grad blue filter layer in multiply mode (higher density at the bottom of the frame) to darken the bottom red sign

At this point, it’s probably worth talking about plugins and filters. The former are either a set of Photoshop actions, or a separate program, that controls the conversion – specifically the luminance translation of each colour channel into a luminance value – and the tonal map of the final file. Whilst they are extremely popular and used by many ‘internet street photographers’ either to save time or because they are unable to get their desired results from a nuts and bolts conversion, I personally avoid them because they do not give you enough fine control, and even worse, everybody’s images that were run through that filter look the same. There is no personality or skill in that.

Photography is arguably art and very much down to personal taste. If you are 100% happy with the way those results look, great; I’m jealous of the amount of time you’ve saved in your workflow. However, claiming this is art is disingenuous; it’s like finding out Ansel Adams shot BW400CN (a B&W film designed to be run through a C41 color processing machine) and developed it at the local pharmacy – instead of Tri-X or Plus-X, controlling his development time and chemical composition, and then cutting precision masks to dodge and burn portions of his subjects.

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That ‘arty’ high contrast, high grain look. It’s actually what heavily pushed Tri-X used to look like, but how many people actually know that firsthand?

There’s a second type of filer that’s useful, and in either form, it performs a similar function to the channel mixer – it either admits or cuts out light that’s of a certain range of wavelengths. The most common example of this is a physical red filter that goes over the end of your lens; the effect is dark skies, because very little of the blue spectrum passes through the red filter and onto the recording medium. It works with digital too, but you have to remember to adjust exposure accordingly, and obviously not use it in color mode. You can also replicate this effect digitally. Add in a new layer, make it one color, and then select the appropriate blending mode; then only do your B&W conversion. There are interesting results obtainable through this method.

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Final image, desaturation + curves + selective dodge and burn + second round of curves + slight palladium tone layer

If you pull back the B&W conversion layer slightly – assuming you didn’t directly apply the conversion to the image – then it’s also possible to use a color layer to create a toning effect; sepia or platinum is probably the most common. You can even use a graduated fill layer to provide a variable effect; this is especially useful for increasing the density of skies, for instance.

Personally, I prefer to shoot color and then convert to B&W; not because I can’t decide upfront how a scene should be presented, but because there’s a lot of flexibility in how I want to handle the conversion later to highlight certain aspects of my subject, or achieve certain tonal looks.

I’ll go into detail on my personal B&W workflow with an end to end example in a future article. MT

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  1. Hi Ming Thein,
    Thanks for sharing the tips/technique. I hadn’t tried gradient map in my conversions, but now that I have seen what it does, it works great—in combination with channel mixing. I have been using SilverEfex which I am happy with overall. But, I’m glad to go back to using Photoshop for better overall control. I would love to see more tips like this, especially for color photography! Thanks.

    • Give it a try. As for color, I’m still figuring out exactly how to do this because web compression of images makes it rather tough to demonstrate.

  2. Great explanation of B&W technique. I have been converting my M9 raw files in Apt. 3 then using a Silver Efex plug-in for B&W, and I knew some control was lacking for me in the results. I had been told about using desaturation in ACR before, as I have CS5, but this is the first time I have seen a clear explanation of some of the techniques. Thanks Ming Thein, this will help my B&W workflow.
    Alan G

    • No problem. As you can probably tell, I’m not a huge fan of plugins…your results tend to look like everybody else, and individual images aren’t quite right.

  3. Reblogged this on Photography Luiz L..

  4. What a fantastic article!

    Ming – would you mind sharing with us how do you process those MM files, thank you ahead!!

  5. Hi Ming, I’m not sure where to ask this, so I hope this post will be OK. In terms of the color cameras you’ve used, have seen any differences in how well their pictures convert to B&W? My current personal project is trying to figure out my lighting and post-processing so I can get close to something like your hacked NEX-5′s B&W images. Needless to say, I’m very far from that right now! I’d say that it looks like my midtones on up are all very quantized: there isn’t a nice smooth tonal transition that seems to be a mark of the lustrous B&W look. At first I thought it was just a personal limitation (and not the fault of the NEX-5N I’m using), but then one day, just for the heck of it, I tried out a conversion on some OM-D E-M5 RAW files I had lying around, and with very little effort, got much closer to my ideal than ever before. So that led me to my question. I’ve also noticed that some of the older vintage lenses don’t do so well, and the more modern, corrected, “clinical” lenses fare much better. And if this inspires you to write a whole article on the differences, I wouldn’t mind either. :)

    • I’m not sure there’s a whole article in there, but what you’re seeing has less to do with color and more to do with the native tonal response of the sensor and dynamic range. The CCD cameras generally do quite well, and some of the newer CMOS ones too. The OMD is one of the better ones, as is the Ricoh GR Digital series. I can convert the NEX-5N if you’re interested, just completed one for another reader earlier in the week.

      • Thanks for your thoughts and the offer. I’m not sure I’m that committed yet! I wanted to make sure I wasn’t out of my mind, and I think my PP technique still has quite a ways to go.

  6. Hi Ming,

    I am now reading through your whole archive – slowly getting there but hopefully I will be able to digest all of your excellent articles. This article in particular made me revisit my current B/W conversion process. I used to batch process and somehow rode into the fad of VSCO (I still believe it is a great preset if you use it as a starting point and not the definitive interpretation of your images). I took a very hard look at my images and process in conversion. It took me 6 hours of experimentation and now have arrived at something more tasteful (I hope). I am now removing batch processing in my system (for non-snapshots at least) and will work harder on my keepers. Thanks again Ming! Without your wonderful articles, I would have not realised that I need to take a different approach.

    Best Regards,


  1. [...] is a nice guy who answers questions fast if you should have some. And he even wrote an article about black & white conversion not so long ago. If you go there, you’ll see at once what Bill and I mean: his blacks are [...]

  2. [...] cover processing workflow in general here, and here for [...]

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