Spectroscopy: Spectral Colors

Does blue plus yellow really make green? In Spectral Colors you can make colors appear from the transmission or absorption spectrum of a solution. Try the exercise below.

Exercise. If bright red Koolaid is colored by a single dye, with a single, broad absorption peak, estimate the wavelength range of maximum absorbance for this Koolaid solution. (Hint: If the Koolaid is red, what color is being transmitted? What colors are being absorbed?) Use the applet below to sketch a spectrum of a solution with a bright red color. Note the wavelengths of maximum absorbance and maximum transmittance.

To sketch an absorption spectrum, first click on the "absorbance" control below the graph. Then click and drag the mouse over the graph in the shape of the desired spectrum. The graph background will change to the color of the solution having the sketched spectrum.

To get numerical data into or out of the graph, click on the "Table" tab.

The color that you see on the screen will vary from the actual color of a real solution due to many factors including the settings and limitations of your monitor as well as the settings and limitations of the color model used by the applet.