You can set the background of your spectra to be either white or black. Go to Project / Preferences ... or type Ctrl/Cmd , and in the General tab you can select your Colour scheme to be either light (for a white background) or dark for a black background. Axis/mouse colours and contour colours for newly loaded spectra will adjust automatically. The chosen colour scheme will be active across all your projects.
You can adjust the contour levels of a spectrum using the Contours Up/Down buttons in the toolbar. To set the contour levels manually, either double-click on a spectrum in the sidebar and go to the Contours tab in the Spectrum Properties dialog box, or right-click in your spectrum and select Contours ... to set the contours for all spectra in that display.
The Contours diaglog lets you set the contour base levels manually. You can also set the multiplier; this determines how close to one another the contours are drawn. Go for 1.1-1.2 to make them very close, or 1.6-1.8 to separate them out more. You can also change the number and colour of the contours and select whether or not to show the positive/negative contours. You can add custom colours by clicking on the colour button. Make sure you select the box you want to place your new custom colour in before adding it, or you will overwrite the first custom colour. Custom colours are stored in your global preferences and will be available to you in other projects.
If you have multiple spectra in one display, you can switch the spectra on/off using the buttons in the spectrum toolbar. You can show/hide the spectrum toolbar by typing SB or right-clicking and toggling Spectrum Toolbar on/off. (You can hide the main toolbar with TB or right-click / Toolbar.)
You can remove a spectrum from a display by right-clicking on the spectrum botton in the toolbar and selecting Remove Spectrum. Add it again by left-dragging it into the module from the sidebar.
You can toggle mouse crosshairs on and off using CH or by going to right mouse menu / Crosshair. You can toggle a double crosshair mode for the mouse on and off using CD or right mouse menu / Double Crosshair. The double crosshair mode will give you crosshairs on both sides of a diagonal.
You can add or remove gridlines to/from your spectrum display by typing GS or going to right mouse menu / Gridlines.
You can your default preferences for the crosshair and gridline options by going to the Spectrum tab in Project / Preferences ... (or type Ctrl/Cmd, to bring up the Preferences dialog box). These will then be the defaults when you open or create another project.
You can change the aspect ratio of a spectrum by scrolling the mouse-wheel on one of the axes. This selectively zooms that axis and has the effect of changing the aspect ratio. To lock the aspect ratio left-click on LOCK in the bottom left hand corner of the spectrum display. See Zooming for more information on aspect ratios and zooming.
If you would like to display your spectrum with a different arrangement of axes, then you can type XY, XZ or YZ to swap those axes. A new module with the new axis arrangement will open up. For more information on flipping spectra and how to set default axis arrangements see Flipping Spectra.