Optical Red

[Henry Wienhold]

Hello Allan
I'm not sure , but Adrian Gottlieb may be refering to a final thin transparent glaze of red in order to give flesh color a warm glow and make the figure stand out more. To give the image that outstanding quality that the old masters were able to do so well, but I could be wrong.

[Allan Rahbek]

Henry, this is most likely the explanation.

By glazing with red you will damp down all other colors relatively more than the red, and thereby make it stand out as stronger in tone and lighter. Optical stronger.

I could not understand why he would need any stronger red than the cadmium he use.

Thanks, Allan

[Steven Sweeney]

I have enquired of Adrian about his use of the term and would hope to have his response anon. Patience will likely be rewarded.

[Steven Sweeney]

Adrian provided the following response:

Optical red is a highly subtle and thin halo of red around a light area. The red exists not on the light object, but on the darkness around it. The use of Optical red can be found in the works of most any master, most noticeably in Rembrandt, Caravaggio, Velazquez, and Bouguereau. I prefer to apply it so that you would only notice it if you already knew to look for it. After all, optical red is merely a tool. I don't feel the need to shout, "Hey! Look! Optical red!!"

In short, optical red tricks the eye into seeing a glare, or greater intensity of light. When the sense of light has already been achieved, optical red adds a second punch, causing the light to truly appear as light.

Has this clarified things?

[Allan Rahbek]

Thanks, this was very informative.

If I have understood it right this will be the effect of blinding.

I believe this tool can be seen clearly in the picture "St. Peter Denying Christ" by Rembrandt.

Not only has he used the red in big parts of the shadows, which creates a glowing temperature to the whole painting and especially the lit parts, he also enforced the tonal contrast in shadow areas close to the light-source.

Allan

[Tony Pro]

I used optical red in this painting... note the "red glow" just on the outside of the profile of the forehead... It's a wonderful concept of giving "life" to any portrait or figure...

Remember, light is tangible believe it or not... so when bright warm light reflects of flesh, it can cast a "glow" or "halo" to produce an atmosphere in the painting.

Hope this helps!

Tony

[Chuck Yokota]

So, if optical red creates the illusion of the brightness of the adjacent light area in the minds of the viewers, does that mean it's just a pigment of their imagination?

[ReNae Stueve]

Originally Posted by Steven Sweeney

Adrian provided the following response:

Steven,

Thank you for the AhhA!! moment. Although I've departed from Portraiture for now, the Optical Red technique applies.

This past weekend my daughter was visiting from Berkeley for a much needed rest. I'd been working on a large banana still life, (trust me it's cool) and while she watched, I applied a deep red into the negative space around the highlight / leading edges. The effect was to "lift" the subject right off the canvas, In her words, Vibrant!!!

Once again, I'm transformed from idiot to savant, at least in her eyes.

I've said this before, but it's worth saying again, to those who may be thinking about joining this forum.

I returned to painting after a 20 year break. Trying to get up to speed, I spent the first few years pouring over posts on all manner of web sites offering artists a voice. After much wasting of time, I've narrowed my list of favorites to this one, only.