Sometimes I prefer to publish my map in gray instead of black. But all newly added QGIS composer items are set to black by default.
For changing the colors more easily and rapidly I created the “Turn Gray” plugin. By default it changes all foreground colors (labels and outlines) to gray. But you are free to choose more cheerful colors too. And for the background as well.
Right now not all composer items are supported, but the map, legend, labels and scale bar do. Tables, arrows and map grids will have to wait.
I hope others will be happy to use this tool as well, that’s the idea behind open source!
An advantage of using map services like WMS and WMTS is that your styling has been done by someone else. But this can turn into a disadvantage as well in case the colours of your overlay are similar to the colours in your remote base layer.
To show this I created an example using the Dutch Top10NL topographic map (WMTS) with my own random polygon layer in random colours on top of it. Because of the bright and colourful Top10NL my own features are hard to distinguish.
In QGIS master (soon QGIS 2.0) I discovered a new feature. For WMS and WMTS layers it is possible to adjust the colours. You can change brightness, saturation and contrast. It is also possible to display the layer in grayscale or adjust the colour (hue), for example to purples. (It’s still a matter of taste…)