Effect on visibility of thin films due to interference

[haruspex]

Sorry, I didn't get you.

Suppose on hitting the film from the left only 5% is reflected. The other 95% reaches the far side of the film, where 75% is reflected. (Is this possible? I don't know.) So then 75% of that is reflected from the LHS, the other 25% emerging. The reflected portion returns to the RHS, 75% of that being reflected and 25% emerging as the third ray directed leftwards.
We have, in the first three rays going leftwards from the film:
5% in the first
95%*75%*25%=15.7% in the second
95%*75%*75%*75%25%=9% in the third

 

[brochesspro]

Suppose on hitting the film from the left only 5% is reflected. The other 95% reaches the far side of the film, where 75% is reflected. (Is this possible? I don't know.) So then 75% of that is reflected from the LHS, the other 25% emerging. The reflected portion returns to the RHS, 75% of that being reflected and 25% emerging as the third ray directed leftwards.
We have, in the first three rays going leftwards from the film:
5% in the first
95%*75%*25%=15.7% in the second
95%*75%*75%*75%25%=9% in the third

So this supports my assumption, right?

 

[haruspex]

So this supports my assumption, right?

That was an explanation of how the third ray to the left could be more significant than the first one, so an analysis that only considers the first two is incomplete.

 

[brochesspro]

That was an explanation of how the third ray to the left could be more significant than the first one, so an analysis that only considers the first two is incomplete.

So in short, no, right?
If so, I think I will stop thinking about this problem.

 

[haruspex]

So in short, no, right?
If so, I think I will stop thinking about this problem.

Good.

 

[brochesspro]

Good.

Thank you for all your help. The others too.