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Discussion Starter · #1 ·
I will try to explain this in as much detail as possible. I am trying to look at degradation of a cellulose paper in a project I am working on at my college. We can take digital images of the objects which consist of a black background, and a white cellulose paper in the middle. Over time the cellulose paper breaks down and we would like to use a digital image software to calculate the area of a specific color change.

For example, when using Adobe Photoshop we can select the white area with a specific tolerance and get areas highlighted, but we can not obtain a quantitative value. Does anyone know any software that could help with this?

Thank you very much.
 

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photoshop should help - its used scientifically for colour change

try using the histogram option with statistics

so open photoshop
window
histogram
arrow at side
statistics

you can also show the red/green/blue hsitogram and stats for a selection of the photo
 

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The histogram gives about as good a representation as you can get. You can look at the total luminosity throughout the range or look at the separate channels. You can use the histogram or just use levels – it is a histogram display too. The actual histogram display is probably better since you don’t want to alter the image.

I would take screenshots of the histogram at various levels of degradation and both in luminosity and in the separate channels. If you can print onto some sort of transparent material you could overlay the histograms physically. If you open the screenshot as an image you can select the background and eliminate it. Then you can pull one onto the other in Photoshop for comparison.

I would crop out the black background to avoid the large spike it will make on the left of the histogram. You can also get luminosity readings from various parts of the image by putting the cursor on it and referring to the Info tab. It gives both the level and comparative amount in the various channels as a digital readout.
 
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