When I look at the overall color of the cactus what I see is a predominance of yellow. Yes, it is a green cactus pad but it has a lot of yellow over all so that is where I start because yellow is going to be my lightest color after white. I painted the entire cactus with yellow working wet on dry and adding water when I needed to move paint. If you are working more level than I have to paint for class, it would be okay to wet the area first then add your color, I just have to make sure my color stays where I put it, it my paper is too wet, all the color will run to the bottom.
In the flower area, I did use the same yellow but one, I diluted it with water so it was lighter, and two, I did paint around where I will have the edges of petals so I have some white highlights, then I let the whole thing dry.
When my paper was dry, I mixed a color for my base color of the cactus pad it was sap green, with touches of yellow and orange. The orange has red in it and slightly grays the green to give it a softer look. On the pad itself, I just quickly put down this color using a scumbling stroke which means strokes going in all directions. This will give the pad texture and it will give you more texture if you work wet on dry paper adding water where you need it. Just do this quickly so you don't stir up the color underneath. While it won't really bother this particular painting if you do, it is good practice for the times you really don't want to mix mud.
On the buds I started in the darkest areas with this color rinsed my brush and with a damp brush, blended the color out from the shadow area with just water to create a graded wash and to start creating a rounded look, I also used a diluted version of this color in the shadow areas of the unopened buds. Again, I let it dry before proceeding. I can use a hair dryer if I want but the paper still needs to be dry to the touch.
The color I used for the shadows I mixed down in that same green color but I added blue and purple with a bit of water to make a dark green color. Again, I started in the shadow area by putting the color down, rinsing my brush and with a damp brush, I pulled the color out but this time I did not go quite as far as before and "dab" your brush a bit to give some texture. Save this color you will need it in a minute.
In the darkest of shadows usually under things like the flowers, and where the buds attach to the pad or between buds or the smaller pad at the bottom, you will need a very dark color, I use a mix of blue with just a touch of purple, the purple goes a long way and can over power in a hurry that's why I say a touch. I am using my angled shaders for all of this painting but with practice you and do this with any brush, I just find I can do a lot with one brush and tend to stick with what I know, this is a good thing because the less you have to think about your equipment the more time you can devote to your painting.
I load my dark blue/purple on to the tip of my brush which was very dry before I loaded it, then placing the tip in the darkest area but placing the entire brush on the paper I paint the dark shadow. If you do it right with either an angled or flat brush the edge that was formed away from where the tip painted should be a soft edge. If it isn't or you are using a round brush, rinse your brush, dry off most of the water and run the damp brush along the outside edge to soften it. To create the cast shadows, add a touch of water to the blue/purple so that it is a bit lighter than what you just did but still dark and paint the shapes of the shadows. Soften any hard outside edges of the shadow with a clean damp brush. Let the pad area dry.
The shadows for the flowers are very delicate so there will be a lot of water in any color you mix for the shadows. I started in that green color I mixed for the first layers so medium shadows – the one I told you to save – and into it I added a bit more yellow, a tiny touch of purple and water. You want a very light gray/green color this color will go under, between and behind the petals and a lot of what you will do is negative paint the shapes of the flower petals. Don't be afraid to use water to dilute the color even more because the color is very subtle and very delicate. Let the flowers dry before adding more color.
On the pad of the cactus where the spikes are, there are subtle ridges to show a ridge you need to give it form with highlights and shadows, even subtle ones. To create a highlight, rinse your brush and with a clean, damp brush lift out a diagonal highlight that is uneven, not a straight line, across the pad. The cactus doesn't have a ruler so the lines meanders a bit, have wide and narrow areas and curve slightly when they come to the edges.
Right next to this lifted highlight, use a diluted form of the shadow color – something dark and cool already on your palette will work – and make a similar shape next to the highlight again it isn't straight or even. Soften any hard lines with a clean damp brush. If you want, you can add a wash of yellow across the highlight, not necessary but do wet the line with water and using the tip of your brush pick up some straight sienna and tap the color in rough circles to create the base of the spikes while the area is wet, the edges will automatically fuzz out.
I also lifted the reddish leaves of the new, smaller pad with my small angled brush and with the same brush, I mixed my napthol red with a touch of sienna for the reddish color of the leaves on the new pad and the buds. Remember that these little leaves are growing over something that is round so they will be curved to go around what they are growing over. In the shadow areas where I have leaves, I added a touch of purple.
If the flowers are dry, you can add more yellow to some of the petals. Don't forget about your highlights you will want to paint around them but don't worry about painting over the shadows with more yellow, it won't hurt the final outcome.
At this point all that is left is the detail and if you are so inclined, feel free, however the last things I did was I lifted out the spikes with the edge of my angle brush using it clean but just a bit damp (if you see dark rings around the areas where you have lifted it is because your brush was too damp and the water ran off your brush and onto your paper) then I added some cast shadows with my shadow color. Because this was just a demo I hadn't done anything with my background but to show off the flowers I used a dark blue/purple and painted around the flowers, the contrast sets the flowers apart from the white of the paper.
Next week I think we will do more basics. I notice that many of you are still struggling with shadowing to create 3D shapes so there will be no reference picts this time, also we will be doing some practice with wet into wet because knowing how your paint works on its own opens up a lot of possibilities.