Wednesday 15 July 2015

Beware an optical illusion's effect on your paintings and drawings

Your eyes are deceiving you! In 1995, an optical illusion published by Edward H. Adelson, a Professor of Vision Science at MIT, drew attention to the fact that our eyes perceive how light or dark an object is based on the lightness or darkness of its neighbouring objects. If you are seeing the illusion below for the first time, you would probably call me crazy if I told you that Square A and Square B have the exact same tonal properties. But they actually do as the subsequent picture shows.

The checker shadow illusion as published by Edward H. Adelson, Professor of Vision Science
When cut out and placed next to each other, the squares A and B are found to be of the same shade

This illusion has implications on our artwork be it paintings or drawings. In essence, the checker shadow illusion highlights our visual system's weakness at being a physical light meter. I believe the same principle is roughly at work when a colour that we paint on our miniatures can sometimes look noticeably different based on which other colours are surrounding it. To illustrate my point, I made a skin tone comparison between the Nocturna Models Le Petit Chaperon and Akelarre Enchantment figures. At first glance, one can arguably assume that the former has a slightly brighter skin tone.   

A light skin tone on the finished Nocturna Models Le Petit Chaperon
A seemingly duskier skin tone on the work-in-progress Akelarre Enchantment

However, upon closer inspection - and when the surrounding colours are removed as to negate their influence - it would seem that the latter i.e. work-in-progress Enchantment figure is the one with the much lighter skin tone. Her skin's seemingly dusky undertones are more apparent when viewed next to her light turquoise dress. Similarly, Le Petit's skin tone is made lighter by the darker contrasts of her red cloak and blue corset. As control, both figures were photographed under the same condition.

Putting both the Nocturna Models miniatures side-by-side for a skin tone comparison
Comparison between skin tones sans surrounding colours

Such optical illusions are more noticeable when drawing with graphite pencils because we are dealing with a gradation of only two colours namely black, white and the resulting grey hues in between. Looking closely at my drawing below, you might notice the highlights/reflected light on the ala (or wing) of Park Joo-Mi's nose looks as bright as the highlights on her left cheekbone. But as the following edited picture shows; this is not the case at all. The illusion is caused by the wing of the nose being located next to the dark shades of the nostril which makes the reflected light look much brighter than it really is. And this illusion caused an error on my part: Highlights on the bridge of her nose have the same tonal value as the wing of the nose when the former should have been brighter. Inconsistencies such as this are among the kinks that I need to iron out before I can improve further.

Finished portrait drawing of Park Joo-Mi
Optical illusion showing reflected light on the ala (or wing) of the nose is darker than it actually looks

My suspicion of this phenomena was first confirmed in a National Geographic Channel show called Brain Games and reaffirmed when I came across this brilliant YouTube video by JD Hilberry. I would strongly advise you watch both sources to better understand how this optical illusion can effect your paintings and drawings. Just being aware of the problem has been a real eye opener for me. Hopefully, this post can bring a similar awareness to those of you who do not yet know, or those that do but just can't quite put your finger on what you may already instinctively know. Either way, may this little bit of information help you as much as it has helped me in my quest to create better art.

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10 comments:

  1. Another fascinating piece and of course perspective, an illusion we now teach early on at school, is of course another artistic illusion. What fascinates me is that much of what we perceive and read visually is done without us realising, the brain simply making a series of decisions that we are apparently unaware of.

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    1. What I wouldn't give to be a fly on the wall of your class. Imagine the cool things I would get to learn. :) It sucks to try and learn stuff by yourself sometimes.
      The mind is such an awesome thing which makes it so much sadder that so many people in the world refuse to use it.

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  2. I teach this illusion too, but I must admit that your photos are much more fascinating than my lessons! Great post...

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    1. Cool ... are you an art teacher or a vision scientist too? I'm sure your lessons make much more sense that my post. :)

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  3. Wow, really interesting and useful post, thanks for sharing!

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    1. No problem luca. I hope it was useful to you.

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  4. I found this illusion so hard to accept that I actually used my computer to check the colours in squares A and B. But you're right - they are the same!

    So, the question then is this: as painters of miniatures, what should we be doing differently on account of this?

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    1. While the illusion above tends to effect graphite pencils drawings more than say a colour painting whether 3D or 2D, the underlying concept is important i.e. that our eyes function poorly as a light meter. I believe it affects how we paint in that we should be aware that colours look different based on their surrounding colours. Based on personal experience, it has stayed my hand in making too many alterations to a certain colour I make before adding its surrounding hues. This was because I was looking at the colour I was painting in comparison to the surrounding grey primed areas (i.e. unpainted areas). When I eventually painted the surrounding colours, I found that the first colour I had laid down now looked different. I hope this makes sense to you. :)

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  5. Wow!
    Very nice work...

    I'm going to look more often here ^^

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    1. Thanks Hiso Hiso ^_^ ... your work is really cool too. I too will be following your blog. :)

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