I'm no expert on how they work, I just know that I like to "work" with them. And, I know, that I've recently (like three days ago) discovered that my favorite ink color is black.
When I became aware of my fondness for black ink, I lined up my current rotation of fountain pens, to clean and refill them with black ink, and I was shocked to discover that I didn't have a single bottle of black ink. I probably have fifty other colors, but no black. So I headed for Amazon.com, plugged in Noodlers (my favorite brand of ink) and black. Two seconds later, my order was placed, and I was ready to go back to whatever I was doing before I discovered that black was my favorite ink color. It was then I noticed at the bottom of Amazon's "thank you for your order page," this message - PEOPLE WHO BUY NOODLERS BLACK INK ALSO BUY NOODLERS HEART OF DARKNESS.
Heart of darkness, I thought, and then I thought, as I unconsciously clicked on the Heart of Darkness image, isn't black ink black ink? Now I know the answer to my question is NO—black is not necessarily black. If there are 50 shades of gray, there are a zillion shades of black. Look at the difference in Noodlers Black and Noodlers Heart of Darkness:
Now I'm waiting for UPS to deliver my bottle of Heart of Darkness, and while I'm waiting, I'm thinking about how this all applies to writing because there too you can find a zillion shades.
In my estimation, Heart of Darkness in writing takes you to the heart of that which is being told—it makes you one with it. Here's an example:
From One Fearful Yellow Eye
First the John D. MacDonald version - which, as you will immediately know, is the one I refer to as The Heart of Darkness version:
We sped north on the Tri-State, and she had that special sense of rhythm of the expert. It is a matter of having the kind of eye which sees everything happening ahead, linked to a computer which estimates what the varying rates of speed will do to the changing pattern by the time you get there. The expert never gives you any feeling of tension or strain in heavy traffic, nor startles other drives. It is a floating drifting feeling, where by the use of the smallest increments and reductions in pedal pressure, and by the most gradual possible changes in direction, the car fits into gaps, flows through them, slides into the lane which will move most swiftly. She sat as tall as she could, chin high, hands at ten after ten, and made no attempt at chatter until the stampede had thinned.
The Black Version of the same passage (mine) -
Seconds after we moved on to the Tri-State, I realized she was an excellent driver. She gave it all of her attention, as she moved easily in and out of the heavy traffic, without disrupting its flow.
If you write, go for the The Heart of Darkness version. You'll enjoy it more and your readers will love it.