Getting more contrast on B&W conversion

Started Mar 17, 2004 | Discussions
Mike Fulton Senior Member • Posts: 1,480
Re: Digital B&W Filters in the Computer

Marc Longwood wrote:

Take this one step further with this neat little trick...

When you shoot black & white film, what do you put on the front of
the lens to alter tone and contrast? Filters. So why not do the
same in the computer.

After you do the above with a Channel Mix adjustment layer above
your color image, you create a Hue Sat adjustment layer between
the color layer and the Chan/Mix layer thus creating a color
filter. All you have to do now is vary the Hue slider (filter
color) until you see the the image you like. You can also adjust
saturation to vary the intensity of your new color filter.

This can give you a SIMILAR effect, but be aware that there may be differences in how much detail is seen in the image, compared to using a filter on the lens when taking the picture.

The reason is simple. When you shoot a picture using a colored filter, you adjust the exposure to compensate for the density of the filter. For example, if you use a Red 25A filter, you probably give 3 stops more exposure.

However, you have to keep in mind that the entire image is not uniformly 3 stops darker. The green and blue portions of your filter are probably 4 to 5 stops darker, while the bright red areas are probably only 1 to 2 stops darker.

If you're giving 3 stops more exposure to compensate for the filter, this means the green and blue areas will be a few stops darker while the red areas get a few stops lighter.

Since all this happens before the image is actually captured, it affects what details are captured on film (or image sensor). You'll lose detail in areas that get very dark and gain detail in areas that get a bit lighter.

But once you take the picture without a filter, the maximum amount of detail in the image is fixed. You can emulate the way that colored filters affect the overall contrast of an image, but the filtering process can't create detail that didn't exist in the original picture.

Just something to keep in mind.


phototakeouter Contributing Member • Posts: 729
Re: How I do it + some examples

Thanks for sharing those, Paul. Those aren't just great conversions, they're stunning photos!


OP Jeff Klofft Veteran Member • Posts: 3,559
I'll second that

Thanks for the advice and inspiration. I'm working with a couple of the techniques suggested. BTW, I too like the toned prints. Thanks again.

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OP Jeff Klofft Veteran Member • Posts: 3,559
I'm working with this method now

Here is a link to that article

I've found that I like the results and the control. I'm also working more with burning and dodging. Here is an example of where I was a couple of days ago and one from last night.

Previous best

Last Night (and there are more improvements that I think I could make, but I was tired)

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