# Absorption Spectrum Using a Spectrophotometer

After using a spectrophotometer, I have obtained absorbance values. To create an absorption spectrum, should I convert these values to percentage absorbance? (I've seen it in textbooks as such)

If I were to convert absorbance to percentage absorbance, would I simply multiply all values by 100%?

• There is no such value as "percentage absorbance." – MaxW Jan 1 '16 at 5:06

This is simple mathematical conversion. Firstly, you find the fraction of each absorbance value.

Let, the absorption spectrum has a three absorbance values say $A_1, A_2$ and $A_3$.

Now, find the fraction of each absorbance as per following:

fraction of $A_1 = A_1/(A_1+A_2+A_3)$

fraction of $A_2 = A_2/(A_1+A_2+A_3)$

fraction of $A_3 = A_3/(A_1+A_2+A_3)$

Now convert all the respective fraction values into percentage as per:

percentage of $A_1 = (\text{fraction of }A_1 \cdot 100)\%$

percentage of $A_2 = (\text{fraction of }A_2 \cdot 100)\%$

percentage of $A_3 = (\text{fraction of }A_3 \cdot 100)\%$