The L,a,b system is used to express the color of a product.

The UV/VIS spectrofotometer measures absorbance at a or more specific wavelenghts to calculate amounts of a certain substance in a solution.

Thus two complete different applications. Search the net for more info.

C.A. (Kees) Kan Thank you Sir

I will do that again

Here,

l* - black (0) to white (100)

a* - green (−) to red (+)

b* - blue (−) to yellow (+)

You can measure absorbance within stipulated wavelength range (Vis/ UV-Vis) for Standard and Sample separately. From these data of standard and sample you can evaluate delta E / color difference.