I've made a list of such topographic maps of favorite Sierra Nevada areas. On most standard 7.5 minute USGS topographic maps, light brown elevation lines are every 40 feet with a darker fifth line at 200 feet intervals. One mile is about 2.63 map inches. Since such vertical lines are always brown, it does not visually communicate absolute altitudes. Thus the main advantage of coloring elevation lines on topos is to provide an improved way to visualize maps. Before I made maps, for decades since the days of only 15 minute quads, I would simply used narrow tip colored markers manually over-coloring map lines and would tend to only color the 1000 foot increments since that usually suffices. Too much added color tends to get cluttered.
In order to start with a high quality data source, I download 7.5 minute maps from:http://libremap.org/data/
Then scale the map to 5.0 inches per mile which is what I eventually print at. My maps are mainly of stream basin headwater areas. For instance have one for the East Fork of Bear Creek and another for the South Fork of Bear Creek. Maps are sized to fit those areas. The main task of course is dealing with the brown elevation lines. I'm an old advanced Photoshop user and the first thing I normallly do is color select all the red and black overlays to the USGS maps that is most of the text and various township and public land boundary lines and then delete them. One reason is that later I put my own improved text in and land boundaries and township lines only detract from visually communicating the topography. Of course some standard maps incorporate shading in a compass direction but I've never been a fan of such maps. The Sierra Nevada has a great many no name features as peaks, lakes, and streams. By making my own maps, I also enjoy adding some of my own names since I've also explored many of the basins, some extensively. At some point not any time soon, I may decide to market some commercially as the quality is good enough.
In order to replace a specific brown line with another color, my strategy is to use the Magic Wand tool to select lines. For instance say the 8000 foot lines on a topo. Then after all those 8000 lines are selected do a global Edit Fill replacement with a different color. An issue is the original brown lines will have open white sections where the deleted red and black lines used to be and there are always a lot of thin open feathered sections on lines especially in steep areas. Such sections need to be over traced. Additionally in cliff areas, multiple brown lines will merge. Thus one needs to isolate lines of interest from such merged areas. Good near eyesite and a good talent for patiently hand tracing over areas of weak broken lines will help. So yeah it can be a lot of work. A fine task for rainy days during winter haha. And note I've also used Gimp though that is rather unpleasantly awkward in some ways for someone used to Photoshop.
Maybe I'll post a small section of one of my maps with a comparison topo link to ACME mapper.