Step-by-step process of crafting a Halloween illustration with watercolor and digital tools

Since taking an illustration class at the School of Visual Arts in New York, I’ve continued to adapt my creative process, blending both digital and traditional tools. While I find technology incredibly useful, I have a deep love for working with hands-on materials—especially watercolor. There’s something magical about the unpredictability of watercolor, how the paint interacts with water, and the way it dries with unique textures and effects.

Here is a behind-the-scenes look at how I create an illustration from start to finish. One of my recent works is a Halloween-themed painting inspired by Brooklyn, New York. Growing up in Spain, Halloween wasn’t a holiday I celebrated, but since moving to the U.S., it has become a beloved tradition, especially for my kids. Even though it’s only September, they’re already asking about costumes and decorations! This illustration captures the wonderful memories of our time in Brooklyn, where we first experienced trick-or-treating with friends.

STEP 1 - Sketching

I begin each illustration with thumbnail sketches to brainstorm ideas. Once I’m satisfied with the composition, I create a more refined sketch using Procreate on my iPad. For this project, it gathered photos of my kids in their Halloween costumes over the years: a pumpkin, a witch, a black cat, a ghost, Spiderman, and Isabella from Encanto. This was an emotional step in this case going through all those memories. I also set up a Pinterest board filled with reference images, illustrations, and other sources of inspiration.

Each element is sketched on its own layer so I can easily adjust the composition and scale. When I’m happy with the final layout, I print the sketch and transfer it onto watercolor paper using a lightbox.

For this illustration, I reused a simplified version of a Brooklyn brownstone I had painted previously, placing it on the left side of the scene. I then sketched the New York City skyline and added a large tree with the moon glowing behind it.

STEP 2 - Choosing the color palette

Choosing colors is one of my favorite parts of the process. Lately, I’ve been experimenting with limited color palettes to create more cohesive illustrations, while also learning how different colors interact and blend together. To decide on the final palette, I create swatches and a color chart, which helps me visualize the overall tone of the piece. With my chosen colors, I make a quick color study to see how everything will look together.

Color chart and color tests

STEP 3 - Painting the main background

In the past, I used to paint the entire illustration all at once. However, after taking my illustration class, I’ve found it more effective to paint individual elements separately and then combine them digitally in Photoshop. This method reduces the risk of mistakes (watercolor can be tricky to correct!), allows me to reuse elements in future illustrations, and offers more flexibility when adjusting the final composition.

For this illustration, I painted the house, the sky with the full moon, the New York skyline, and the street separately.

STEP 4 - Painting the pumpkins and trick-or-treaters

With the background complete, I moved on to painting the kids in their Halloween costumes. I based their outfits on photos of my own children, as well as reference images from free photo resources like Pexels and Unsplash. To maintain cohesion, I used the same limited color palette for the costumes and pumpkins.

Watercolor painting of the background and other elements of the illustration

STEP 5 - Assembling Everything in photoshop and adding final touches

The final step is assembling all the individual elements in Photoshop. I scan the watercolor paintings and clean them up digitally, placing each element on its own layer. This allows me to adjust the composition until everything fits just right. Once I’m satisfied, I add digital finishing touches, such as glowing light from the lamps, shadows for the kids, and subtle highlights on the tree branches to capture the moonlight.

Editing in Photoshop

And with that, the illustration is complete!

Final Illustration - Halloween in Brooklyn

I hope this gave you a glimpse into my illustration process. If you’re looking for some festive Halloween décor, this print is now available in my Etsy store. Thank you for following along!