Optical and magnetic properties of orthoferrite platelets with the optical axis normal to the surface have been investigated. A simple calculation has been performed indicating that a considerable increase of optical contrast between domains magnetized in opposite directions can be expected in such platelets when compared to the contrast obtainable in platelets with the crystalline "c" axis perpendicular to the surface. A numerical calculation has also beem performed for the stability range of a skew-bubble occuring in an orthoferrite platelet in which the magnetization is not perpendicular to the surface. It was found that this range is smaller and shifted to the lower bias fields than that for a normal bubble, amd that the ellipticity of a skew-bubble is larger. Experiments confirmed the theoretical prediction. On the basis of experimental results it was concluded that the shape of the skew-bubble wall is rather complex in thin platelet. This hypothesis has been confirmed to a certain degree by experiments performed on platelets with different thicknesses.