Requirement 4b — Tape and Pencil Method

You can create a complete set of fingerprints without fingerprint ink, official cards, or a police station. This simple method—using tape, pencil, and paper—has been used for years in schools and forensic science classes. It’s exactly how forensic examiners sometimes develop latent fingerprints at crime scenes. You’re going to learn this technique.

Why This Method Works

This technique works because it mimics how forensic examiners develop latent fingerprints at crime scenes. A latent fingerprint is invisible—left behind by the oils and sweat on your skin. To make it visible, examiners use various methods. The tape-and-pencil method is one of the simplest and oldest.

When you rub your finger across pencil graphite, the graphite particles stick to the oils and ridges on your fingerprint, making it visible. When you press clear tape over it, the graphite transfers to the tape and you have a permanent record.

What You’ll Need

• Clear adhesive tape (regular transparent tape works best; avoid colored or frosted tape)
• A wooden pencil (regular #2 pencil is fine) or pencil lead shavings
• Plain paper (white paper works best for visibility)
• A flat surface to work on
• Optional: A pencil sharpener (to create graphite shavings if you want finer particles)

The Step-by-Step Process

Step 1: Create Your Graphite Source

You have two options:

Option A: Pencil Rubbing

Take your pencil and lightly scribble on a piece of scratch paper (not the one you’ll use for your final record). You’re creating a layer of graphite that you can rub your finger across. Make a dark smudge about 2 inches by 2 inches.

Option B: Pencil Shavings

If you want even finer graphite particles, sharpen your pencil and let the shavings fall onto a piece of paper. You’ll then rub your finger in the shavings. This creates a fine, even layer of graphite particles.

Step 2: Coat Your Finger in Graphite

Take the finger you want to record (let’s say your right index finger) and rub it back and forth across the graphite layer you created. Keep rubbing until your fingertip is well-covered with dark graphite. You should see your fingerprint patterns becoming visible on your finger as the graphite sticks to the ridges.

You want a good coating of graphite, but not so much that it’s a thick, muddy layer. If you can still see your ridge patterns clearly on your finger, you have the right amount.

Step 3: Prepare Your Tape

Tear off a piece of clear adhesive tape about 3 to 4 inches long. Have it ready to press down.

Step 4: Press the Tape onto Your Graphite-Coated Finger

This is the critical step:

1. Position the tape: Place one end of the tape against the bottom edge of your fingerprint (the side closest to your palm).
2. Roll the tape slowly and steadily up your finger, covering the entire fingertip and part of the surrounding area.
3. Press firmly: As you roll, use your other hand to press the tape down firmly so the graphite transfers to the tape.
4. Smooth it out: Once the tape is in place, smooth out any air bubbles so the tape makes full contact with your finger.

Step 5: Remove the Tape

Gently peel the tape away from your finger. You should see your fingerprint in graphite particles stuck to the tape.

Step 6: Mount the Tape on Paper

Press the tape—graphite side up (so the ridge patterns are visible)—onto your sheet of plain paper. Press it down firmly and smooth out any air bubbles. Label the tape with the finger name and date (e.g., “Right Index, 3/8/2025”).

Step 7: Repeat for All Fingers

Repeat steps 1-6 for all ten fingers, creating a complete set of fingerprints on your paper. You should have ten tape impressions arranged in order: right thumb through right little, then left thumb through left little.

Alternative: Recording Another Person’s Fingerprints

The requirement allows you to record your own fingerprints or someone else’s (with permission). To take someone else’s fingerprints:

1. Have them coat their finger in graphite (same process as step 2).
2. They can either press their finger onto a piece of tape, or you can press the tape onto their finger (both work).
3. Mount the tape on paper.
4. Have them sign the paper to verify you have their fingerprints.

This is especially useful if you want to compare fingerprints from multiple people and show that each person has unique patterns.

What You’ve Created

You’ve created a permanent record of your (or another person’s) fingerprints using a simple method that requires no special materials. This tape-and-graphite method is:

• Inexpensive: Most homes have tape, pencil, and paper.
• Reversible: You’re not using ink that stains; you can wash your hands and the graphite comes off.
• Educational: You’ve experienced a version of the forensic techniques used to develop latent fingerprints.
• Replicable: You can repeat this process multiple times and always create clear fingerprints.

Comparing Your Two Methods

If you completed Requirement 4a (official fingerprint card), you now have two different records of your fingerprints. Compare them:

• Ink impressions: Clear, dark, professional-looking. These are what law enforcement uses.
• Tape impressions: Lighter, more textured, showing the graphite particles. These are what you see when forensic examiners develop latent prints.

Both show your ridge patterns. Both are valid. But they look different because of the materials used. This is actually useful in forensic science—examiners become skilled at recognizing fingerprints in different forms: ink, graphite, blood, dust, paint, etc.