Converting to B&W

markjmaclean

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Hello,

I took a couple of photos today and decided that they would be better in black and white. My question is, how do you achieve this (with photoshop).

As far as I can see, there are the following methods:

1. Desaturate

2. Change the mode of the image to greyscale (although this seems to need to be changed back to RGB afterwards in order to use filters etc.)
3. Channel Mixer - then adjust the reg green and blue for the desired effect.

Anyway, here's 2 pics that I converted to B&W. I would appreciate any opinion on whether the conversion was successful (I used method 3) - and also, which method you find most successful for making images black and white (and why).

The Birdman:
http://www.flickr.com/photos/markmaclean/121908362/

The Statue:
http://www.flickr.com/photos/markmaclean/121907789/

I feel like I'm always taking advice and not giving it - maybe one day I can return the favour.
--
Mark
http://www.flickr.com/photos/markmaclean/sets
 
The birdman: I find the face of the man too dark. You can sometimes achieve a better effect with a custom white balance before you make it b/w, or mixing the channels differently.

The statue: it's perfect.
--
oVan
 
I mean altering afterwards. You should experiment with what happens to green and red colors when you convert them to b/w. Having a custom white balance (sometimes one that is "totally wrong") gives a better b/w or sepia conversion.
--
oVan
 
Desaturate is correct. Adjusting "saturation" to 0 in hue/saturation will have the same effect.
 
The statue is a bit more successful than the man with birds, to my eye, as it expresses a better tonal range. The man and birds shot looks somewhat muddy in the areas that should be nicely detailed and highlighted. Both do not reach a maximum black and have a too soft, low contrast appearance.

Here's my B&W rendering workflow:
-----

This procedure is used with Photoshop CS2. I use a variant of the "Channel Mixer" formula, working entirely in Adjustment Layers. Some of it is automated, but some decisions have to be made per picture as well when you get to the finishing stage. The concept is fairly simple ... the devil is in the details.

Here's the fundamental idea:
  • Be sure you're working on a well calibrated monitor and know how to use profiles in printing. You can't make a decent print consistently if your system is not calibrated properly.
  • When you apply RAW conversion processing, don't make the mistake of presuming that you're going to make a perfect conversion that needs no further editing. Seek to output into RGB as much data as your image file contains, and presume you're going to be shaping and manipulating that data later. This means 16bit@channel output to RGB in PSD or TIFF formats.
The rest of the workflow is at the RGB channel level so applies to DNG, PEF, PSD, TIFF, or JPEG files equally. Of course, if you're working in JPEG files, due to the 8bit@channel nature of the files, editability is less, but that doesn't mean the workflow breaks down.

1) Look at the photograph before you begin and decide what you want to do with it. High key, low key ... decide where the IMPORTANT details are and where you are willing to let highlight and shadow detail go away. This is the most important step ... You cannnot achieve a goal without knowing what it is.

2) I apply via a script an Adjustment Layer using the Channel Mixer tool with the settings R=20, G=70, B=5 percents. This is a starting point and not necessarily the best mix for all scenes. You can get a feel for how to manipulate this by turning the adjustment layer off and then looking at each channel in B&W seperately for a moment (the Cmd/Cntrl , 1, 2, 3 keypresses let you do this very quickly and easily). Tweak the Channel Mixer settings to suit where you've made decisions about how you want your photo to appear in B&W ... if you have a lot of detail in the Red channel and not much in the Green or Blue, bias the mix to Red. etc.

3) If the image has several different kinds of lighting in it that changes the ideal mix in different areas, you can either
  • insert Curves adjustment layers under the Channel Mixer layer and tweak the curves for each channel independently, with masking to separate the different areas.
  • Mask the channel mixer adjustment layer and use a second or third one to change the mix, with masks again to localize the differences.
(I tend to prefer using the Curves technique as I find it easier to compress or expand a tonal gradient with it. In general, I use step three about 20% of the time.)

At this point you should have a close-to-final rough of your B&W rendering. Up to here, most photos will look like what you get from processing B&W film at a photofinisher. NOW it's time to make your image shine. ... Study your image again and identify what needs to be done to reach your goal.

4) I usually do overall sharpening for the full resolution image at this point as it will change local contrasts and edge effects that you want to take into account when doing tonal edits. Select the background layer, make a layer copy (no destructive edits to the base image...) and use CS2's Smart Sharpening tools. Small adjustments applied incrementally work best. Watch the important areas of the image at 100 and 200% scalings to detect haloing and artifact growth. Back off when you see them ... they look unnatural. Different images require different sharpenings...

5) Now, back to tonal shaping. Curves Adjustment Layers with masking inserted above the channel mixer adjustment layer will operate only on the grayscale tonality. Again, small steps, one area at a time, with selective area masking ... I watch a particular area, get it the way I want, then fill the mask with black and brush in the adjustment with a soft edged brush and a slow fill rate until I get it the way I want. I build up each area of the photograph in this fashion, a little at a time, merging layers as appropriate when I reach certain points to simplify the document and save space.

6) Once you have everything done as well as you can manage, the rest of the workflow to render for the web is pretty fast. Be sure to save your work in PSD format to preserve all the layers (you should be doing that often throughout the editing process...). I do a profile conversion to sRGB, which auto-flattens the layers and uses the full 16-bit data in calculations. Next, from Pentax full-resolution files, I use "Image-> Image Size.." and resample the image to either 620 pixels for a horizontal or 530 pixels for a vertical, let the other dimension fall where it may, and set 72ppi as resolution (helps with some of the applications I use that honor the density and sizing information for on-screen display). At this point, you will often notice that the image has gotten a little darker. A Curves adjustment layer to tweak the tonal curve upwards, reflatten again. Sometimes a minor application of USM (.8 pixels, 30-40%, threshold=2) to resharpen. Then use "Image-> Mode-> 8-bit" to reduce it for JPEG output, and "File-> Save As..." to JPEG, quality 6.

You're done.

The key isn't just to follow the formula. The real work is:

1) Evaluate the image and understand your goals in rendering it to B&W.

2) Understand what each of the steps is meant to do so that you can modify the processing to suit a particular image problem.

Godfrey
 
Wow, thanks Godfrey.

You make my efforts at this task seem exactly what they are...paltry! Many thanks for sharing your workflow with us. This really gives me a great insight into how a professional might do it. The key is in knowing the final goal before you start - this makes a great deal of sense and yet, I never really thought about it. I was more trying to improve the look without any specific goal in mind.

I appreciate your taking the time to respond in full.

regards

Mark
--
Mark
http://www.flickr.com/photos/markmaclean/sets
 
that's what I usually do. But you will notice the same white balance trick has an impact also on desaturated photos.
--
oVan
 
It makes my reply pretty paltry as well, not to mention "wrong" I suppose. I would just desaturate and use curves to brighten up any areas that are too dark. I couldn't stand to go through much more pp as I'm not fussy in that area, but I'm no pro either! :\
 
Well it's good to know I'm not being completely foolish. I don't doubt there's some benefit in talking time to make adjustments more carefully, it's just not something I'd enjoy getting caught up in.
 
and has more personality than the Birdman, if not the birds. Godfrey's post is worth the price of admission.
John Dunn
 
Godfrey,

thanks again for all of your suggestions. I tried tonight to work through your list and boy, did it take me a while. Probably about 1 hour for the photo. By the end of it, however, I'd learned a whole stack of new things I didn't know about photoshow, and for that, I'm in your debt.

I've replaced the second photo above with the newer version. I hope that I've managed to clear up some of the problem areas that you mentioned before.



ANyway, I'll keep working on it.

Thanks again.

regards

Mark

--
Mark
http://www.flickr.com/photos/markmaclean/sets
 
That's improved, but you're still not expressing the full tonal range .. both whites and blacks are not at the full range they should be, which means that gray levels in the middle are compressed and too close together. Take a look at it using the histogram in Photoshop.

I took a copy of the JPEG image and did a Levels adjustment to clip both highlights and shadows, then added a small curve to weight the correction a little better. I then added a light vigness to shape the light for you. The results in comparison can be seen at

http://homepage.mac.com/godders/birdman/

If my edit looks too bright on your screen, one issue might be monitor calibration.

Godfrey
Godfrey,

thanks again for all of your suggestions. I tried tonight to work
through your list and boy, did it take me a while. Probably about
1 hour for the photo. By the end of it, however, I'd learned a
whole stack of new things I didn't know about photoshow, and for
that, I'm in your debt.

I've replaced the second photo above with the newer version. I
hope that I've managed to clear up some of the problem areas that
you mentioned before.

http://static.flickr.com/43/121908135_f7efa7fee2_b.jpg

ANyway, I'll keep working on it.

Thanks again.

regards

Mark

--
Mark
http://www.flickr.com/photos/markmaclean/sets
 
My monitor is correctly calibrated. I think you just made it a little bit too bright: in the original photo, you see a nice white lighting on the back of the man's head, suggesting sunlight from the back. In your version, this almost fades into the nearly white walls. I would make that wall just a tiny bit darker.
Just my .02€
--
oVan -> http://ovan.be
 
My monitor is correctly calibrated. I think you just made it a
little bit too bright: in the original photo, you see a nice white
lighting on the back of the man's head, suggesting sunlight from
the back. In your version, this almost fades into the nearly white
walls. I would make that wall just a tiny bit darker.
Two comments in response:
  • Your monitor is calibrated to gamma 1.8 or 2.2? That can also make a difference, also whether you are viewing the image with a browser that honors embedded profiles. My system is Mac OS X v10.4.5, the monitor is calbrated with a base gamma 1.8 setting. I view the images with the Safari browser, which honors profiles.
  • I did the corrections as an example. I saw the nice light on the back of the neck and saw that effect get more subdued in my corrections.. If I had the original 16-bit file to work with, and it were my presentation image, I'd have spent more time developing the expression of that nice light, certainly. The point of the example was to show how to expand the tonalities to express the full tonal scale, not to produce the very best rendering possible. That would take a bit more time and effort... :-)
Godfrey
 

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