I have been thinking about this for a while and the appearance of a retro look Spanish AF T6* onto the database was the final push that I needed.

There is more to monochrome than greyscale and I hope to show it here.

The original image has its faults, it's just for illustration. I hold my hand up right now and admit that this subject did not come out well in mono, some do some don't.
Colour


A straight desaturation using the Hue/Saturation tool (Ctrl + U)


A greyscale conversion (Image, Mode, Greyscale)


The Channel Mixer, Red 30, Green 60 and Blue 10%, Monochrome box ticked.

The Channel Mixer, Red 10, Green 60 and Blue 30%, Monochrome box ticked.

The Channel Mixer, Red 30, Green 40 and Blue 30%, Monochrome box ticked.


If you look at the photos above you will see that each method affects the colours in different ways. Note how the first two conversions treat the grass and the blue cheat line.
My preferred method is to use the channel mixer with starting points of 30, 60, & 10% and tailor the picture to the colours in the picture, in this instance concentrating more on the greens than the blues.

The beauty of it is there is no right way to make a mono image, you do it to portray a mood rather than colours.

By coincidence I was surfing Photography sites this morning and I came across this one. http://www.photography.com/black-and-white.php This text is extracted straight from the Black & White page
"Why Take Black and White Photos?
With the vibrant colors available in modern film and with digital cameras, why opt for black and white photos at all? Depending on the subject, a photographer may use black and white film to create a stark, somber tone for his photos. This quality has paved the way for black and white photography in photojournalism.

The vibrancy of color can, at times, actually detract from the desired photographic effect. Subtle effects of texture and lighting that can be lost in color photographs will stand out in black and white photography.

Black and white photos can add an air of romance, class, timelessness and mystery to otherwise ordinary photographs. A run-of-the-mill color photo may look entirely different when seen in black and white. For this reason, both wedding and gothic photography have embraced the timeless quality of black and white photos."

So for that retro look to an old piston aircraft of a century series fighter let your imagination take you back to monochrome.
Remember - a manipulation rejection awaits if you use a monochrome conversion on a modern aircraft.

* http://www.jetphotos.net/viewphoto.php?id=5894913 The main colour is yellow so concentrate on the blue and green in the conversion