Curious effect of light on transparent surfaces

While painting a glass bottle I noticed that the highlight did not seem as bright as the same light beam that hit the wall inside the bottle.
Here’s an example of what I’m referring to-

In a book by Ted Seth Jacobs (“Light for the artist”) the reason is explained-
“light striking the part of a rounded glass facing the source may not be as bright as the light ‘emerging’ from the side further away. this, of coarse, is quite the opposite of the effects on a matte surface. the light ‘exiting’ a round glass object often seems to undergo a lens-magnification effect”.

Although the light is indeed brighter I chose to tone it down in order to “push back” the further wall of the glass bottle (otherwise it “jumped forward” to the ground plane).

I was wondering- when faced with a certain effect in the setup that “doesn"t look right” but has a justification in the way light behaves physically, which one would you go for?


Intuitively, I would say: go with what you think looks best on the canvas/suits your work the most. So this might be either one. But if it is an artefact or something that really stands out, I guess you have to be careful handling it.


Hi Stella,

I agree with Bert. I would go with what looks the best in the finished piece, even if it isn’t what is in your setup. I would approach the situation by first faithfully representing what’s there and if something doesn’t look right change it.

1 Like

I would agree with the others - the only thing that matters is the quality of the finished painting.

“Light for the Artist” is a wonderful book, by the way. It’s one of my stalwarts.

1 Like

Thank you for your input everyone :smiley:
I did exactly what Leah suggested and it’s great to hear the way different artist approach this challenge.

I would like to add to the conversation my main concern when thinking about this subject-
One problem with doing what looks best on the canvas is that some effect might look wrong to me because of a bias I might have of how light should behave.
In other words, I could wrongly think it looks bad because I’m accustomed to the way highlights behave in classical order of light on matte objects. This while someone well versed in painting glass objects might think it looks great.

1 Like

I agree, a great book!

I think I’ll start a thread with book suggestions, it’s always fun to get a glance at someone’s artistic library :nerd:

1 Like