What is the correct use of the "RGB2Lab" function in this situation?

Hi, what I am looking to do is an analysis on the color change of a sample over time.

What I thought of doing is the following:

1- A mask of the first photo that will be used in all the following ones. In this way observe only the sample.

2- Using the mask to obtain the average value of the RGB channels of the sample in each of the photos.

3- Use the "RGB2Lab" function to obtain the values in Lab mode for each photo.

4-From these last values calculate the color difference "Delta E" for each of the photos with respect to the first one.

My doubts are then the following (if you have any recommendation for any of the above steps I will also be grateful, I am new to image analysis and I learned about Lab mode last week):

Does it make sense to occupy Lab mode as I am doing?

From what I understand the "RGB2Lab" function has other inputs that are related to the light used. If I used a white fluorescent light I should use the light standard "F" or am I wrong?

However this standard is not available for the function, any advice?

This is the sample:

EDIT: I was quick to ask the question myself. But I found some links to other answered questions that, I think, encapsulate everything I asked.

https://la.mathworks.com/matlabcentral/answers/23013-makecform-srgb2lab?#comment_443644

https://la.mathworks.com/matlabcentral/answers/797742-how-to-separate-the-rgb-channels-from-an-image-and-get-the-average-of-each-rgb-channel-separetly?s_tid=sug_su

[Image Analyst]

So are all your questions answered then?

[Vicente]

Yes!

Thanks.