It can be difficult to get the colors just right on complicated subjects, especially ones with lots of natural color variation, like flowers. I will show you how to take advantage of gradient maps to color your flowers more quickly and with more pleasing and natural results. I only use basic brushes in this tutorial, and the principles can be applied to any flower painting, not only the one I demonstrate here.

Do a basic outline

The outline can be rough. Remember to let the petals overlap and bend. If you draw each one from a slightly different angle this will make your flower look fluffy and full. Use quick lines until you get a general shape you like.

Next, refine the lines. I used the g pen to get a nice crisp line on a new layer. Every time I add something new, I like to do it on a new layer until I'm satisfied that it isn't going to need adjustments later.

Fill it in (grayscale)

Don't even worry about color yet; focus on form and contrast. I used the basic running edge watercolor brush set to black to add depth and form. Even rough strokes will be fine at this point. Keep in mind the parts of the petal that face the light source should be lighter while the center and the areas the petals overlap one another should be darker. I find that using a separate layer for each petal at this stage lets me work more quickly without fear of ruining other parts of the flower.

The petal on the far right of the picture above is how it looks when I add the grayscale. This can be blended using strokes running from petal tip to base, giving a light texture to the petal without destroying its form. The petals on the left are more refined because they have been blended (using the basic blender brush). I like to keep drawings fairly clean, so you can see where I have used the pen selection tool to draw around the exterior of a petal to delete excess color. (It's fine to do this at the end as well, if it doesn't distract you.)

Add shadows and highlights

I used a basic airbrush to add black where the shadows should be deeper.

I used a smaller version of the same airbrush to add highlights and petal details with white. I recommend doing this on a separate layer so you can adjust the opacity if you think you over did it.

Clarify and fill center details

I used a white g pen on a new layer to clarify the center details of the flower. I wanted these to help create some contrast, so I made them brighter. If you design a flower with lighter petals, you may prefer to make these a darker gray. Use photographs of real flowers for inspiration.

Use a black airbrush to add depth.

Here, I made the other layers invisible in order to more easily follow the guidelines I had sketched earlier for the very center of the flower. I used the running edge watercolor brush with black to add color and blended it. Consider texture as you blend, but it doesn't have to be perfect. You should wait to make major adjustments when you can see all the layers at once and gauge their effect.

Adjust the layers and add details

Here is a before and after screenshot. I chose to reduce my base layer of fill to about 70%. Play with opacity in your layers to find the effect you prefer.

Plants naturally have little imperfections and deviations in texture and color. You can imitate this by adding some details to your flower. You could use a pen and carefully apply them, or you can add a few splatters of light and dark gray using the droplet and/or spray airbrush. Lower the opacity on this layer so that these flecks don't draw too much attention to themselves but instead enhance the painting as a whole.

Another way you can continue to adjust your contrast is to use a level corrections layer (Layer > New Correction Layer > Level Correction). I pulled the left arrow towards the center to increase the depth of my shadows.

Add color with a gradient map

I wanted to use two different gradient maps for this flower, so I selected the center portions with the pen selection tool. I turned this selection into a selection layer (Select > Convert to Selection Layer).

This is what a selection layer looks like. The green area can now be colored using a different gradient map than the rest of the flower.

If you don't want to color your background or the rest of your paper as well, you will want to create an additional selection layer that covers the rest of your flower. If you included greenery, you will want to make that separate too.

Add a gradient map (Layer > New Correction Layer > Gradient Map). The box that pops up will have pre-made gradients that you can test. Here I applied one of the sunset options. Change the color at any point of a gradient by clicking on the smaller arrow below the gradient bar, then clicking on the box of color beside the eyedropper on the center-right of the box. This will pull up a color map for you to select a color from.

You can try many different colors without fear because the tone and texture you already created will be preserved, no matter how many gradients and color combinations you try. Because each gradient map exists on a separate layer, you can easily erase it or hide it to return to your original grayscale painting.

You can use this method to make flowers look realistic or fantastical. You can create a grayscale bouquet or a garden, coloring each flower separately, and then overlay the entire picture with a low opacity gradient map to imitate ambient light. Using gradient maps to color flowers allows you to experiment with color more quickly and easily than beginning with a single color of paint to start with. Enjoy making your beautiful flowers!