Hi.
I am investigating the change colour in a photo sequement from bright green to dark green. For this I used the histogram mean values of green, red, blue as well as the luminance.
I thought I could see a trend in the values and establish a ratio to determine the increase in color intensity.
The problem is: the darker the color becomes, the less green light comes through and the green value is displayed less.
Do you have any idea how I can use the software to document the desired increase in color intensity using a histogram?
Thanks!
Welcome to the community GMZ!
Not sure if this will help or not. Try
1.Make a gradient out of your greens - lightest will be your foreground and darkest will be your background.
2.Open a small blank canvas and stroke the green gradient on it making sure you are on linear.
Open your histogram tab - add it if you dont have one yet.
Down the bottom of that tab will give you a lot of information.
Many things to sift through so check it out , Just incase your answer is there.
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Welcome to the forum!
What you need to do is to factor out the luminance component, and consider the saturation values. Converting the image to HSV and extracting the S channel for given H (green) values may give you what you need…
Or somesuch… 
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Hi Glenn.
Thank you very much for your reply! I will try out your suggestion.
Have a nice day!
GMZ
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Hello Susan.
Thank you very much for your reply and the detailed description. I will give it a try!
Have a nice day!
GMZ
It quite complicated given that values are gamma-corrected. This has been discussed recently around here.
The histogram mean isn’t going to help you much anyway because an operation like adding contrast doesn’t change the mean much, and if it changes the mean, just shifting the values to achieve the same mean on another picture is not going to do the same thing.
If you want to reproduce color changes between two pictures, you need a CLUT.
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Hi, thank you very much for the feedback and the corresponding information.
BR
GMZ