B&W retouching

Retouch in color, then convert to B&W, or vice versa?

Nill

In B&W green and red are the same. So what you see in color, what adustments you make in color may not be represented in your previsualized B&W after conversion. In my work flow the first thing I do is convert in RAW, then I begin global and selective manipulation of the image.

Gary

You mean you do your B&W conversion in RAW? That's what I've been doing for the most part. BTW I understand (having had it recently brought to my attention) that it's particularly important to do B&W conversions to 16-bit so you don't end up working with only 256 steps of gray.

Nill

Nill Toulme said:

You mean you do your B&W conversion in RAW? That's what I've been doing for the most part. BTW I understand (having had it recently brought to my attention) that it's particularly important to do B&W conversions to 16-bit so you don't end up working with only 256 steps of gray.

Nill

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I dunno Nill ... on paper yes the dif between 8 bit and 16 bit is significant. But to the human eye do you think you can see a significant difference if you had more than 256 shades of gray??? I would work on an image in 8 bit then again in 16 bit and see if the 16 bit is any smoother in the transitions than the 8 bit. Hell, Adams only worked with ten zone of gray.

Gary

Heh, yes but he didn't have only ten shades of gray in his prints. He was an analog guy, remember? ;-)

I think it's pretty easy to produce banding when you're working with only 256 shades.

Nill

Gary Ayala said:

In B&W green and red are the same.

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This may be generally true, but NOT necessarily true when you are talking people's skin imperfections like zits.

Anyway, I tend to convert first then retouch since imperfections that appear in the color version may either be reduced to nothing or accentuated by an order of magnitude... As for converting in raw, I do that sometimes (not all), but do it by desaturating -- NOT converting to grayscale -- and leave the image in 16-bit mode.

Cheers,

When I convert to B&W in RAW I use the B&W camera profile for C1 that turned up on Digital Outback a few years ago. It almost always gives me pleasing results unless I'm looking for something more dramatic and out of the ordinary.

Nill

Gary Ayala said:

I dunno Nill ... on paper yes the dif between 8 bit and 16 bit is significant. But to the human eye do you think you can see a significant difference if you had more than 256 shades of gray??? I would work on an image in 8 bit then again in 16 bit and see if the 16 bit is any smoother in the transitions than the 8 bit. Hell, Adams only worked with ten zone of gray.

Gary

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Hi Gary and Nill,

My response it far longer than the minum required becasue this is a good opportunity to provide a starting platform for people considering B&W photography. So you already know most of what I'll present.

Is 16 BIT needed? Not in a simple conversion to B&W (by picking one channel or discarded all the color info) with no major S-curves after that. So, if in a simple preserves separation of shapes and patterns, 8 BIT is fine!

Where is 16 BIT better? Finer work! We can exploit fine steps to reassign tiny portions of the color curves to a particular spread of grays. With 16 BIT, we can simply do that better as we have a finer color dropper. With 8 BIT color, closely positioned hues might not be so easily selected and handled separately.

Using filters on the lens. B&W photographers have always used colored filters at the time of film exposure. By decreasing the incoming light of a particular wavelength range to reach the film, the final distribution of tone is controlled to the photographers design. However, in the digital age, some particular colored light, (that Ansel Adams might have excluded), can be remapped to new shades of gray. So now, we, (in our naivety, perhaps), can draw our picture as we want. It's this capability, allowing infinite control, that allows an amazing palette of creativity. Not that we can all be Ansel Adams, no that has been done and the guy's dead. But it does allow us ruin our pictures ad infinitum or with insight and discipline perhaps, make one's mark in B&W work.

So now we come to the order of doing things. There's no reason, in principle why reassignments can't be done during shooting if one knows exactly what one wants! Pros also may have the skill to do this at the time of taking the picture as they also do in perfect framing of the scene.

Making a B&W photograph today? One can use scanned film or a digital capture and work from there. My choice at that point? Usually I want everything in the file. That way I can think about choices creatively for much longer. So, even if one uses a filter to exclude some of the incoming light, (for example to get the mountains beyond the mist), the digital file needs to be made to a black and white file and somehow, natural color has to go!

So here's how I make my conversion to B&W:

1. Colors are diverting attention from form and theme

A Simple conversion to grayscale in 8 BIT with discarding color information will often be fine.

2. Discarding color info obscures wanted differences

So, for example, a pattern on a dress or carpet might vanish so a picture may lose its impact. Here I use two layers: Hue Sat and Channel mixer with the grayscale box checked. This allows remapping of colors to tones with great versatility. When we to discriminate close colors or else drastically change the file, (with aggressive luminosity curves, for example), use 16 BIT!

3. Change meaning and impact of image by changes in what's light and dark.

As #2 above

4. More versatile creative work covering "all the above"

Work with CMYK and RGB separately in Lightzone or similar and then recombine layers to taste or else use a specialized program that does the same thing with a simple interface in one step. Working with channels allows us to aggressively deal with noise regionally and locally. A really noisy channel can be corrected or actually dropped or only used sparingly for one local object.

Asher

Nill Toulme said:

When I convert to B&W in RAW I use the B&W camera profile for C1 that turned up on Digital Outback a few years ago. It almost always gives me pleasing results unless I'm looking for something more dramatic and out of the ordinary.

Nill

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I assume that was an RGB saturation profile, so 16-bit output should still be possible... Again, beneficial over 8 if one wants to push pixels around significantly...

The profile does allow 16-bit output.

The other side of this coin, I suppose, is that color images intended for B&W conversion at a stage later than the RAW conversion should also be converted to 16-bit, for the same reasons.

Nill