Perfect black and white conversion, Gimp tutorial
Desaturation is the worst solution for black and white photos with Gimp.
Black and white photography, also known as
monochrome, is the older way to shoot photos.
If you want to use Gimp for simulate a black and white film there are several things you need to know: In a monochrome photo, the observator will be more interested and attracted by the shapes of the image, so try to shoot a subject that is clearly recognizable from the background.
Black and white photos can be
more difficult to understand for the viewers, so you can have good
results with textures or abstract images, that will become less
understandable and more attractive.
Another characteristics of black and white pictures is that the absence of color leaves more space to imagination. In some cases (generally portraits) the photos will be more expressive.
If you want to get a good black and white picture with Gimp, there is a better way than desaturate the colors, let's see how:
The best tool in Gimp for black and white pictures is called Channel Mixer, it allows us to create black and white images with the modification of three color channels.
You can find Channel Mixer in Colors - Channel - Channel Mixer.
In the right screenshot, you can notice that the sum of red green and blue is 100 (100+0+0) and generally is a good idea to change parameters keeping the result of 100 when you sum all factors.
The red channel modify the contrast of the picture.
The green channel enhance or reduce the details of photograph.
The blue channel affects the noise.
A good solution for most of your black and white pictures, expecially landscapes, can be the following one:
Notice that the result of 60+11-70=100
With this method you can emphatize the details, as you an see in the next comparison.
Another tool that you should know for black and white conversion with Gimp is Color - Color Balance Tool.
If you want to convert in black and white a portrait photo, you can change the dominant color before desaturate with color mixer, and the result will be completely different. For this example i used the wrinkles of an old man that I found in internet (no old man photos in my selection). If you change Color balance to red, the black and white will enhance details and defects, such as wrinkles. If the balance is green, the details will be more smooth.
The meaning is that if you need to convert in black and white with Gimp the photograph an old fisherman, you should use a different color balance than if you photograph a 20 years old girl model.