What Is Luminosity?

[alexgarcia]

In my study of egg tempera one word that seems to continually emerge is "luminosity". In trying to learn egg tempera I am wondering how can I acheive that luminosity but I am not completely clear what it means to have a luminous painting? How do you explain luminousity in egg tempera painting or how do you understand it? Also how can one determine if a painting has that characteristic?

[brianhendrickson]

I think it refers to the degree to which light seems to pass into and bounce back through the layers of your paint. Since egg tempera painters (generally) paint with multiple transluscent glazes the effect of light scattering in this manner is especially pronounced, as if each layer of paint is a razor thin sheet of colored glass.

[brianhendrickson]

By the way, did you recently redesign your website? I like it very much...simple and classy.

[Dennis H]

I believe it's like the government's definition of pornography: You know it when you see it.
Seriously, some paintings seem to have an inner glow as if they emit light themselves. It may occur in watercolors, oils, and of course egg tempera. It can be a result of transparent or translucent applications of paint, but it also is due in part to sensitive choices made in color and value. I've seen transparent watercolor and tempera paintings that were as dead as black holes, yet I've found certain opaque acrylic and gouache treatments that put forth a palpable effect of "luminosity."
I think, just hold the idea of luminous paint in the back of your mind as you view paintings in museums, galleries, and in your studio. When you sense a kind of ethereal glow to a work, study that painting well and try to see what that particular artist did to achieve it. And look at the dead painting next to it to see why that one didn't.
Brian is right, though. ET by its nature is conducive to getting a luminous surface, but you do have to try to allow it to happen.
D

[turlogh]

I think it is very skillful and accurate depiction of the effects of light on form. It helps if the lighting is dramatic. It can be done in ET, oil, watercolor, or any medium that allows subtle gradations.

[alexgarcia]

By the way, did you recently redesign your website? I like it very much...simple and classy.

Yes. Thank you Brian.

Thankyou Dennis and Turlough your insights are very helpful.

[Dimitris C. Milionis]

Alex Garcia @ http://www.alexogarcia.com , I enjoyed your work, and found your revised web site very clean, simple to use and neat, Bravo! 8-)

[alexgarcia]

Thankyou Dimitris.

[jeff]

This interests me. Luminosity just means the amount of light given off, so it is probably the wrong term for what is intended. Reading Daniel Thompsons "The practise of Tempera painting" he uses a different term to describe the effect: opalescence. He even gives a good description about how to go about acheiving it.
1. Not too many layers of paint
2. paint new layers at the point where the underlying layer and the new layer have more or less the same tonality.

I did some tests of the differences between egg tempera and watercolour (gum tempera) and pastels (straight pigment). The results were interesting because they show that egg tempera does not alter the colour of the raw pigment very much compared to watercolour. Pastels have the highest luminosity, then egg tempera, then watercolour. Also the dispersion of the pigment in egg tempera is very even - which gives if a particular softness that watecolour can't acheive. This is the origin of the story I think.

jeffB