GIMP Guru

May 7, 2004

Ask the Guru : The Path to B&W Enlightenment

Filed under: asktheguru — Tags: , , , — Eric Jeschke @ 10:30 pm

O Master, what is the path to B&W enlightenment?

Dear Guru, I got a new Nikon D70 3 days ago. My wife is quite upset about my “expensive toys” and tries to fault digital cameras in general and the D70 in particular whenever possible.

She says: but can it do B&W. I say: Sure. I take a photo of my favorite driftwood (wood.jpg) and convert it, as suggested by your tutorial (ch. mixer), and get (wood-bw-o.jpg).

wood.jpg
wood-bw-o.jpg

This obviously is greeted with lots of scorn. Look at (pier.jpg) (A scan of a print I made from a B&W film negative), she says. This is closer to how a B&W should look (Of course she thinks a screen is no good either, only a print is, but that’s another story.)

I tried Pushing the contrast way up, brightness a little down, then added some noise (Filter/Noise/Noisify) to get some grain, and get something like (wood-bw.jpg)

pier.jpg
wood-bw.jpg

My wife (An artist, painter, BTW) is not happy with that too.

Any enlightenment will be greatly appreciated and might stop a divorce

Thanks, Joseph


I love this question!

Your wife sounds like a lot of folks in our local photo club here–“pooh pooh digital” no matter how good the image looks. I’m not sure that you can do about that, vis-a-vis the divorce. How about a nice candlelight dinner for two, instead?

I like your picture. The highlights are just slightly blown out, and after conversion to B&W it just accentuates that a bit, but it is not overwhelming by any means, just wanted to draw it to your attention.

When faced with a B&W conversion, I always start by decomposing to separate R-G-B images to see what each channel has to offer (this is a good step before channel mixing anyway, so you know what you are mixing). After doing this with your color image, I liked the blue channel the best. Often the blue channel is noisy, but with your new D70 it was very clean. The blue channel often has the best contrast, so if you are looking for a contrasty B&W like the pier image, blue is a good base. After playing with channel mixing a bit, I felt that the green and red channels didn’t really add anything interesting, so I discarded them.

I then ran an unsharp mask on it with something like radius=1.4, amount=.26, threshold=4 to highlight the lines in the image, since that is a big part of what makes it work. The result is (try1.jpg). I would stop here, speaking for myself. The result is a little more contrasty than your first B&W attempt, but not so much that the shadows are all blocked up like your second attempt.

try1.jpg
compare to: wood-bw-o.jpg, his 1st attempt

I tried adding grain, as described in my tutorial here, but I decided that it didn’t really add to this image, and really made it worse. Grain can help add interest to large smooth areas of tone, but your image has lots of texture already. The silky smooth digital capture works to your advantage here, in my opinion.

If you really want to boost the contrast further, try a “local contrast enhancement”. The basic idea is to run unsharp mask with an absurdly high radius, low amount, and zero threshold. The result is shown in (try2.jpg) It’s a little too over the top for me, but see if your wife likes this any better.

Best Regards,
–Eric

try2.jpg
compare to: wood-bw.jpg, his 2nd attempt

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1 Comment »

  1. Hi Gimp Guru,

    I’m quite new to Gimp and have been looking for a tutorial on how to bring parts of the background in to the foreground. I have an image of myself sitting down that I cut and pasted to a background of flowers in a field. At the moment in doesn’t look quite right and gives the impression I am hovering above the flowers rather than blending in amongst them. How do I bring some of the flowers in front of my foreground image? I’m assuming this is possible? Thanking you in advance for any help on this! Bless you.

    Comment by jaime7722 — July 20, 2010 @ 12:53 pm


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