This is almost impossible to answer in a concise way. Engraving output is the result of a complicated mix of factors, and understanding how to prepare an image for engraving is about as deep a topic as can be covered here.
I mean this with all respect: Just judging by your question, I’d say there is a lot of reading ahead of you. It’s kind of hard to know exactly what you mean, since we’re all sort of learning the best ways to phrase these things, but I’ll start with 2 assumptions:
- you want to get away from bold black and white logo designs into something with shades of grey.
- I’ll assume you’re looking at non-PG materials
With those 2 assumptions out of the way:
Your first question is about how you think – do you think in terms of fixed power settings first, or in terms of image first? I tend to think image-first, so let’s go with that.
My first step is to convert the image to greyscale, then use curves to pump my contrast to run from full white to full black on the source image. Once I do that, I adjust my engrave settings to correspond to the end result I want.
How settings affect end result is in itself a huge deep topic, so I won’t get too far into it here but for most materials slower = darker, higher power = darker, more LPI = darker.
I do it this way (image-first, with power following) because it allows the greatest dynamic range in the image, which gives me more variation in my shades in the engrave. Think “separation of channels”, if you’re a print nerd. This method also separates the image preparation from your choices later, like materials and settings. It gives you the greatest flexibility in the UI when you go to do your engrave.
But, you asked how to get to certain colors. That’s going to add in yet another massive variable: your material choice. Some woods engrave with almost no discoloration (Wenge), some engrave to rich jet black (Mahogany), some engrave to a caramel brown (Birch ply), some to a nutty brown (Maple). You can spend hours and hours fooling with materials and settings before settling on a tone/setting combo that works for you.
Try searching for “engrave test template”, see what you find there.
By now you’re either nodding your head, or you’re like “This is word salad”. If you’re with me, great, then I’d say you should go experiment. If not, I’d say do a lot of reading about engraving in the forums. It’s easy to engrave, but to really fine-tune your result is a deep topic.