Photoshop Calculations for B&W Images
One area of photography where I’ve been consistently disappointed in the past is conversion of digital photographs to black and white. There are some photos that just work better when they’re in black and white, it’s undeniable. And we see so much vivid colour photography around, including HDR (High Dynamic Range) imaging and various filtering that to some extent it’s come full circle. It’s at a point where once again a high quality black and white photograph stands out from the crowd.
In the past I’ve had mediocre results from the in-camera black and white conversion, and also from using Image / Mode / Grayscale on the Photoshop menu. Image / Adjust / Desaturate is just as disappointing. The images, no matter how impressive in colour, reverted to a flat and uninspiring compromise. However, after reading several resources on using Photoshop Calculations (located in the Photoshop menu as Images / Calculations) the results are impressive.
A quick example on my photoblog of weathered and textured boards were the result of initial experimentation with the Calculations settings.
So what are calculations? They’re where you have access to mathematical functions which were once the domain of engineers. For example, you might want to isolate certain channels so you can lift a fingerprint from a digital photo. The bottom line is that using Calculations you have a dramatically increased power to tweak your shot to it’s potential as a black and white.
When you open the Calculations window a quick play around with the settings will show you better than I could ever explain. Suffice it to say that you have 2 channels to work with (each has grey, red, blue and green), a drop down list for your blending mode, and an opacity level. I’m led to believe that an opacity greater than 30% would lead to the second channel having a greater influence, but you can correct me there if I’m wrong.
To save your image as black and white it’s important to realise that first you should select New Document from the bottom drop down list, and when the image is displayed in Photoshop again select Image / Mode / Grayscale. You can then save your document as black and white or work on it further in Photoshop.
If you have a low quality or ordinary colour photo there probably isn’t much Calculations can do to improve the depth of field, composition or other factors. Therefore a conversion to black and white might be a waste of time. However, if you’ve got something nice but which isn’t quite working in colour Calculations might be the answer. I’m a big fan of black and white photography.
November 22nd, 2008 at 3:16 am
Steven, have you used the adjustment->black and white feature? you can fine tune the channels there. It’s a newer feature of Photoshop.
Normally when I try to stylize a color photo to BW, I use B&W conversion, then I use curve to adjust each channel. Of course, how much I adjust depends on how much I want the B&W version to stay true to the original.
Here are some Photoshop actions for B&W styling: http://maanistudios.deviantart.com/art/Black-and-White-PS-Actions-90259398
November 22nd, 2008 at 7:27 am
Jin, thanks for the tip. Yes I’ve been using calculations then adjusting the curve, which seems to give me a lot of control to black and whites.
I have to confess to having an older Photoshop on my home computer though, unfortunately. Something to save up for
Thanks for the tip. I’m now envious of all the missing newer options.
November 23rd, 2008 at 12:46 pm
By the way, a good video tutorial on using the new black and white feature is available on Digital Camera Magazine.