Outlook includes several properties you can use to define the appearance of controls in your form: ForeColor, BackColor, BackStyle, BorderColor, BorderStyle, and SpecialEffect.
For ForeColor and BackColor, you can use the color scheme defined by your system, or you can use a custom color that you pick from the color palette. Using a system color, such as Menu Text, ensures that your form matches the colors and palette used by your applications. Custom colors do not always appear the same across systems and screen resolutions, but they do offer the widest choice of colors.
Outlook supports transparency, the display of whatever is behind an object instead of its background, in two areas: the background of certain controls and in bitmaps used on certain controls.
You can show a bitmap on many controls. Certain controls support transparent bitmaps รน that is, bitmaps in which one or more background colors are transparent. Bitmap transparency is not controlled by any control property; it is controlled by the color of the lower-left pixel in the image. Outlook does not provide a way to edit a bitmap and make it transparent; you must use a picture editor for this purpose.
Bitmaps are always transparent on the following controls: CheckBox, CommandButton, Label, OptionButton, and ToggleButton. In Outlook, the following do not support transparent bitmaps: the form, Frame control, Image control, and MultiPage control.
Transparent pictures sometimes have a hazy appearance. If you do not like this appearance, show the picture on a control that supports opaque images. If you use a transparent bitmap on a control that does not support transparent bitmaps, the bitmap appears correctly, but you can't see what's behind the bitmap.
Use a system color for a background or foreground
Use a custom color for the background or foreground of a control