int readExtraLine() throws Exception {
		int nSurfaces;
		edgeFractionBase = defaultEdgeFractionBase;
		edgeFractionRange = defaultEdgeFractionRange;
		colorFractionBase = defaultColorFractionBase;
		colorFractionRange = defaultColorFractionRange;
		if (negativeAtomCount) {
			line = br.readLine();
			Logger.info("Reading extra orbital/JVXL information line: " + line);
			nSurfaces = parseInt(line);
			isJvxl = (nSurfaces < 0);
			if (isJvxl) {
				nSurfaces = -nSurfaces;
				Logger.info("jvxl file surfaces: " + nSurfaces);
				int ich;
				if ((ich = parseInt()) == Integer.MIN_VALUE) {
					Logger.info("using default edge fraction base and range");
				}
				else {
					edgeFractionBase = ich;
					edgeFractionRange = parseInt();
				}
				if ((ich = parseInt()) == Integer.MIN_VALUE) {
					Logger.info("using default color fraction base and range");
				}
				else {
					colorFractionBase = ich;
					colorFractionRange = parseInt();
				}
			}
		}
		else {
			nSurfaces = 1;
		}
		return nSurfaces;
	}