Greens in light and shade

[Allan Rahbek]

Thomasin,
If my understanding is close enough you are asking about: "how to paint a convincing light effect?"

No matter what the local colors are you will have to change them a bit according to the temperature of the light.
If the light temperature is warm you will add yellow / orange / red to the lit side and the respectable contrast colors in the shadow, furthermore you will add a lighter value in the light and a darker in the shadows.

If your picture is a Lemon on a green table in a warm light it will be like this: the lit side of the lemon is a cadmium medium and the shadow be blue green.

If the light is cold: the lit side of the lemon is a bluish lemon yellow and the shadow olive green.

About reflected light you will have to practice it in black and white because the values must be right too.

To make a light effect convincing you must obey the laws. A light surface reflects more light into a shadow than a dark one and so on....

[Alexandra Tyng]

Thomasin,

Cadmiums are great in shadows, but all you really need to do is mix them with their complements, rather than making a separate mixture of burnt sienna+ultramarine blue and then adding the cadmium.

cad yellow light+ultramarine violet
cad yellow deep+ultramarine blue
cad orange+ultramarine blue (=more violet grey)
cad orange+pthalo blue
cad red light+pthalo green

The greys achieved this way can be as light or dark as you wish, or as cool or warm as you wish.

The shadow color should also contain the color of the object itself.

To add reflected light, ideally the paint in the shadow should still be wet. Whatever the color of the object that is reflecting into the shadow, that same color could theoretically be used to create the reflected light.
As far as greens go, I use a lot in my landscape paintings. The ones I prefer are:

Phthalo green: extremely strong pigment, transparent and dark, bluish, can be used sparingly for very light, clear greenish-blue colors.
sap green: dark, transparent, good for nature, foliage, etc. especially when mixed with siennas and umbers, cools when mixed with white. chromium oxide: opaque, covers easily, cool, soothing, great for foliage of eastern white pine and other cool leaves, very cool and grayish when mixed with white. Nice basic green when mixed with sap. I think that, of these greens, sap is the only one I would tend not to use in shadows. As Allan said, getting the right value is all important--reflected light should always read as part of the shadow.

[Thomasin Dewhurst]

Thank-you, both of you. You're right about watching the values, Allan. And, Alex, Your suggestion of cadmium and ultramarines without the white helped me see where I was going (or where I might be going) wrong (I haven't tried anything out yet). I think I must use white too much in the shadows areas, thus everything ends up in the mid-tone range. I use white like a crutch, I think because it reminds me of clay and I have the illusion of modelling the face and figure, and so I feel white is necessary to render contours and planes in the shadow areas too. So I am very excited by your cadmium mix examples, Alex. Yay! I'll go and get some this morning and try it out.

Allan - I am going to push forward with more confident areas of shadow in my drawings which, having a mostly a 2 year old model for them, tend to be (very) quick line sketches - but so good for training the eye. Anyway, I am going to look hard at the value changes. I am finding more and more that you can't get away from the established rules. Even if you snub them and go your own route for a while, you find that your best discoveries have already been discovered and used for decades already. It's more an expanding on the established rules to find your voice, rather than a breaking away from them.

My kingdom for cadmium!

Well this ended up more about shadows than green highlights, but perhaps that will work itself out with stronger, warmer, less chalky shadows.

[Alexandra Tyng]

Thomasin, glad to be of some help. I don't want to leave you with the impression that you can't mix white into the mixtures of cads+complementary colors. You can, and might want to, if the object is a light color and therefore has a relatively light shadow. But of course you can also get a very dark value with these mixtures.

[Thomasin Dewhurst]

Thanks Alex. No, I realised about the white and that I still could add it, but I am just so pleased at the oppportunity you've given me to conquer my fear of dark darks that I thought I'd put white on hold for a bit to see what happens.