Sherif, I suggest colormeters as the first option. The results are reliable and the models on the market give you the opportunity to make calculations (determine color differences, for example) and besides to calculate for the most common info (at least, in most papers where color is an evaluated variable): hue angle and chroma. If you do not have a chromameter (and no means, at the moment, to purchase one) colorcharts (from the Royal Horticultural Society) are usefull as well (these are much cheaper than the chromameters).  I have some papers out in which I have plenty of data on mango color evaluations. Hope that info was usefull. Regards, Rjbender

Thank you very much for your answer

Dear Sherif,

Fruit skin color could be measured using a colorimeter. Color parameters expresses as tristimulus colorimeter measurements that is L*, a*, b*, C, and H◦. Negative L* values indicates darkness, and positive L* values indicates lightness. Negative a* values indicates green color, and positive a* values indicates red color. Positive b* values indicates a more yellow color, and negative b* values indicates blue color. The chroma (C) value, calculates as C = (a*2 + b*2)1/2, indicates color intensity or saturation. Hue angle, a parameter that has been shown to be effective in predicting visual color appearance could be calculated using the formula H◦ = tan−1(b*/a*), where 0◦ or 360◦ = red-purple, 90◦ = yellow, 180◦ = green, and 270◦ = blue

Best regards

Dear. Mohammadreza Pourghayoumi

thank you very for your answer .please if you have  some paper in this work send it to me

 Thank you very much