Zoran, I am currently struggling with a painting that includes some very pale yellow clivias. I don't have major problems with the highlights and the areas where the petals are back-lit by the sun, but need some advice on the parts that are in the shade. My intuition is to mix in some complementary colour of yellow to tone it down. I haven't it tried yet, but I think I should add dioxazine purple (PV23) to my Winsor Yellow (PY74) to darken it sufficiently to create believable shadows on the petals.
You have painted the parts of your lemons that are in the shade convincingly, so would appreciate some tips from you or anyone else reading this.
Hey Hermes, thank you for your kind comments... as for yellow, I know that it is hard to go into shadow.
Most probably you did already most of the things that I will go about bellow, but this would be a process if I was in your shoes. And, quite important - in studio environment because if it is a photo from outside or painting done outside there might be some differences.
First, I would arrange and organize lights and darks, meaning separate values ahead of time. Very important not to get confused there or mix them, otherwise we would be all over the place. Keep lightest part for the end and highlight as a touch. Fall of light is usually very steep, meaning that from light to shadow it goes quickly, so you will need at least 2 or 3 values between lightest light (facing light source) and core shadow. Classic order of light has 9 steps including shadow.
Next, with this approach, shadow color stays in "family" of local color of the object - most of the time (exceptions are reflected lights into the shadow of object of some high chroma/intensity surrounding it - let's say bright red cloth next to white sphere).
So, we need to find dark pale yellow, right? Usually, it is raw umber
or something close to it. Burnt umber is orange. In your case, you wanted to try getting pale yellow shadow by mixing yellow and bit of purple and that would certainly take out yellow chroma but also move it toward grey
since yellow cancels purple and opposite. If petals are grey, there is a match. But, raw umber
has no high chroma, it is low in value (good for shadows) and in yellow family so therefore no need to go with complementary colors to tone down in the shadow. But, also we need to count in ambient light such as sky or foliage (if outside or photo) that will influence the color. Raw umber+ little yellow will get you high(er) chroma shadow in yellow family and if you want to tone it down without going into grey, I would try raw umber and white, match a same value and add it bit by bit to raw umber+yellow shadow mix in same value until chroma and value of the object matches. This is called "bracketing" since yellow borders orange and green on a color wheel and you want local yellow to go more cool and green instead of orange but lower in value at the same time. Raw umber has some green in it as well. You can play with pure purple parts mix in the same value and/or different chroma around the edges or next to it as background. It is a bit trial and error. But, I like to keep it in the family as much as I can - and no, I am not Italian
. Also, it is quite hard to match every color in nature, specially shadows but I found that going for direct match and putting it as it is, very often doesn't give me results that I imagined because painting and 2D surface has different rules and it might start looking quite flat and unconvincing so it is nice to have a play of color even if we don't see it in particular object and even in shadows. It is hard to see on a photo of this lemon, but I used couple of strokes of pale, low value purple next to core shadow on shadow part of lemon. Also, as Terri noticed, there is some burnt umber low value and less chromatic by adding blue+white in cast shadow etc.
If I may suggest one more thing. It would be a good habit to create a poster study before large painting, something like 5" by 7", just to resolve issues of value and color. It doesn't have to be precise or anything, simple small study. Here is one of a painting that I wanted to do over the summer but didn't have enough time that took about 45min to an hour:
Hopefully, you found this useful and let me know if you need anything else. As mentioned before, it is only an opinion and not necessarily correct but maybe it will work out.
All the best.
P.S. it is a long post, dear God... did not edit it at all, so my apologies if something doesn't make sense