Please note: this costume is "50 Shades of Grey," not "Fifty Shades of Grey."
My husband wanted a simple costume for Halloween. This is what we came up with. Neither of us has read the book "Fifty Shades of Grey." While this makes it difficult to build a costume around the characters, we decided to interpret the title more literally and made a "50 Shades of Grey" costume.

Step 1: Supplies

This will produce one t-shirt with roughly painted blocks of color in fifty different shades of grey.

You need:
One T-shirt (preferably grey)
Wide Masking Tape (1.5 - 2 inches wide)
Paint Brush
Acrylic Craft Paints in white, black, red, yellow, and blue.
Textile Medium (designed to be used with acrylic craft paints)
Permanent Marker or Fabric Marker
5 cups or bowls (for mixing paint)
5 plastic plates (for mixing paint)
Names for 50 types of grey (find my list in Step 6)

Step 2: Prep

If your shirt is new, wash and dry it.

Cut your wide making tape into 50 relatively equal lengths. I did this by laying the tape in strips onto a cutting mat and then using a paper cutting wheel and acrylic grid ruler. For a large man's shirt, I cut 2" wide tape into 3" strips. It really filled the front of the shirt well. For smaller shirts, us narrower tape and cut into smaller lengths.

Lay the shirt, front side up, on a flat surface. Slide a piece of flat cardboard, plastic, or other material into the shirt to prevent bleeding paint from transferring to the back of the shirt.

Lay your pieces of tape out in whatever pattern you'd like, with the edges of the pieces just touching their neighbors (no gaps). For this large man's shirt, 5 columns of 10 was ideal.

Finally, apply a tape border around the entire grid of tape.

Step 3: Mixing Paint

I used Tablespoons to measure each "part" in the ratios.

This required 3-2oz bottles of black paint, 3-2oz bottles of white paint, 2-2oz bottles textile medium, and less than a bottle each of yellow, red, and blue paints. However, you can use smaller amounts.

I used too much paint. You could easily cut the amount of paint in half and still get enough for a single finished shirt.

You'll want 5 containers (disposable cups, bowls, etc.)

Label the containers 1, 2, 3, 4, 5.
Add 3 parts Textile (fabric painting) medium to each container.
Add black and white paint to each container in the following amounts:
Container 1 - 5 parts white, 1 part black
Container 2 - 4 parts white, 2 parts black
Container 3 - 3 parts white, 3 parts black
Container 4 - 2 parts white, 4 parts black
Container 5 - 1 part white, 5 parts black

Step 4: Painting the Shirt; the First 20 Shades

Either remove 5 random pieces of tape from the grid (not touching--you want the edges to be as neat as possible) or follow a pattern. Carefully set aside the pieces of tape. You may need them later.

Using a disposable brush apply paint colors 1-5 on these squares. (Total: 5 shades)

Divide each container of paint into three parts onto individual plastic plates.

On every plate, add a squirt of yellow paint to one pool of paint; add a squirt of red paint to one pool of paint; add blue paint to the last pool of paint. One at a time, mix the color into the grey paint, then remove a piece of tape from the grid and paint the new color. Clean the brush between colors (or not, it's up to you). (Total: 5+15=20 shades)

Cover the plates of paint with plastic wrap and allow the paint on the shirt to dry. It shouldn't take more than an hour or so.

Step 5: Painting the Shirt; the Final 30 Shades

Once the paint is dry, you may apply the tape over the painted squares (you might want to mark them with an X or something to identify the painted squares. If you want to free-hand the squares between the borders of paint, don't reapply the tape.

Consider leaving one square unpainted, to be the shade of grey of the shirt (if you used a grey shirt).

In each pool of red-grey paint on each plate, add a squirt of blue paint. Mix this in and apply to a fresh square. (Total: 20+5=25)

In each pool of blue-grey paint on each plate, add a squirt of yellow paint. Mix this in and apply to a fresh square. (Total: 25+5=30)

In each pool of yellow-grey paint on each plate, add a squirt of red paint. Mix this in and apply to a fresh square. (Total: 30+5=35)

In each plate, mix together all of the colors of paint thoroughly, Apply to a fresh square. (Total: 35+5=40)

In each plate, add a squirt of yellow paint. Mix this in and apply to a fresh square. (Total: 40+4=45)

In each plate, add a squirt of blue or red paint. Mix this in and apply to a fresh square. (Total: 45+5=50)

At this point, you should have 50 squares of paint on the front of your shirt!

Let the paint dry. For best results, follow the directions on the bottles of textile medium for drying wait times and for setting the paint. Mine says to wait 24-48 hours before ironing to set the paints.

Step 6: Naming

Once the paint is dry and cured according to the directions on your textile medium, you can name your colors. This is optional but adds another element of fun to the shirt. I have developed a list of 50 names. Use your own or pick-and-choose what you like from this list. Be prepared to have people stand in front of you, reading your chest.

Use a permanent marker or fabric marker to write the names. Set according to the instructions on your markers.

Color Names: