Is Acrylic Paint Waterproof? Three Liquitex Mistakes That Cost Me $1,200

The Short Answer: Acrylic Paint Is Not Waterproof

Acrylic paint is not waterproof. It's water-resistant after full cure — and the difference between "dry" and "cured" cost our art program $1,200 in 2022. I varnished 42 student paintings two days after the paint felt dry. The Liquitex acrylic varnish did its job: it sealed the paintings. The problem is, it sealed in moisture still leaving the paint layers, and every canvas bloomed with cloudy white patches.

Fast version:

• Is acrylic paint waterproof? No, not truly. Water-resistant after curing (7–14 days, not 20 minutes).
• Do you need Liquitex acrylic varnish? If the work matters and will ship, sell, or hang, yes. But only on a fully cured painting.
• Are Liquitex paint markers worth it? Yes, for opaque paint in marker form. Just don't use them as highlighters.

Why I Have a Strong Opinion

I've handled art supply orders for a mid-size school district for seven years. In that time, I've personally made nine significant buying or usage mistakes, totaling roughly $4,300 in wasted budget. The varnish disaster was the most expensive. The marker mix-up was the most embarrassing.

In my first year (2018), I made the classic error: I approved an order for Liquitex Professional paint markers and assumed "marker" meant the same kind of tool as the translucent highlighters in our supply cabinet. It does not.

Mistake One: Paint Markers Are Not Highlighters

A student used a white Liquitex paint marker to "highlight" key sentences on a research handout. It looked good on the desk. The text underneath vanished. By the time anyone spotted it, 90 students had the worksheet.

We reprinted the handouts — about $40 in paper and toner — but the bigger cost was the interruption. An entire art history session became a cleanup discussion about opaque vs. translucent media. Not ideal. Not the end of the world either. But entirely avoidable.

Here's the thing: Liquitex paint markers are excellent at one job — putting opaque paint down precisely in marker form. They're for dark paper, canvas details, and sign work. They are not highlighters. A highlighter is translucent ink designed to add color while keeping text readable. A paint marker is opaque paint that covers whatever is underneath. Different tools, different look, different lesson plan.

If you want translucent color, use Liquitex soft body acrylic diluted with water. The ratio varies by color — honestly, I've never fully understood why. My best guess is pigment particle size. (Note to self: I really should document this in the teacher orientation packet.)

Mistake Two: Varnish Before Cure = $1,200 in Bloomed Canvas

In September 2022, we had a student exhibition at a local gallery. Forty-two canvases, all acrylic, all painted with Liquitex heavy body paints. They looked dry. They felt dry. I approved the varnishing step two days after the last brushstroke.

What I didn't account for: acrylic paint dries in 20–30 minutes but cures over 7–14 days. Drying is the water evaporating from the surface. Curing is the polymer film fully forming — the paint particles fusing together into a stable, continuous layer. Varnish belongs on the cured film. If you seal too early:

• The varnish forms a skin while moisture is still escaping the paint layers.
• That trapped moisture clouds the paint. It's called blooming (or blushing).
• In a humid climate — our classroom pushes 70% humidity in September — the problem gets worse.

Result: white patches under the varnish on 40 of 42 canvases. We had to strip and redo the varnish, and some paintings needed touch-up. Cost: roughly $600 in varnish and solvent, plus two weekends of my time, which I value at another $600. $1,200, straight into the trash (metaphorically — the canvases survived; the deadline didn't).

We didn't have a formal cure-time check process before that. Now we do: a simple label-and-date system that marks the last brushstroke day and blocks the varnish shelf until 14 days have passed. In March 2024, that checklist stopped me from making the same mistake again.

Five minutes of verification beats five days of correction.

The Waterproof Question

"Is acrylic paint waterproof?" Around here, that's a parent question, usually a week before the art show, holding a painting with something vaguely sticky on it.

The honest answer, broken down:

• Wet paint: washes off with water. Not waterproof.
• Dry but not cured (first 7 days): water won't instantly ruin it, but moisture can soften the film. Not waterproof.
• Fully cured (2+ weeks): genuinely water-resistant. It won't dissolve under a faucet, but prolonged submersion or constant dampness can soften and peel the film, especially on non-porous surfaces.
• Cured plus varnished: the closest you'll get to waterproof. That's the combination I trust — and why I still order Liquitex acrylic varnish in bulk.

What I mean by "waterproof" in a practical sense: wipe it with a damp cloth. Ship it without a plastic sleeve. Hang it in a bathroom without immediate damage. Unvarnished acrylic in the same conditions? A gamble.

What the Discount Calculator Taught Me

After the varnish disaster, I built a simple spreadsheet — our team calls it the discount calculator — to compare per-unit costs across set sizes, bulk discounts, and varnish coverage rates. It looks boring. It saves us money on every order.

Key findings:

• Bigger sets aren't always cheaper per marker. A 12-pack of Liquitex paint markers has a better per-marker price than a 6-pack. But if your classes only use four colors, the per-use cost tells a different story. The calculator caught a 15% cost overrun in our February order because I was comparing list prices instead of cost per color after the discount.
• Varnish cost per square foot is the real number. Liquitex acrylic varnish bottles come in several sizes, and the biggest jug isn't always the best deal once you check the coverage rate on the technical data sheet. The calculator made me check that math.
• Cheaper brands aren't automatically cheaper. A budget acrylic brand quoted at 40% below Liquitex's list price. After accounting for redo rates and color shifting, the real difference was about 11% per completed painting. We stayed with Liquitex. (Prices as of January 2025; verify current rates.)

What the Standards Say

Two industry references deserve a mention if you're making the case for Liquitex in a school budget.

First, color consistency. Pantone's matching system sets a tolerance of Delta E < 2 for brand-critical colors. We don't own a spectrophotometer, but the concept still matters: our Liquitex professional colors have stayed visibly consistent across three batches since 2022, while a cheaper test brand shifted noticeably on the reds between two batches in Q3 2024. In a classroom, that means repeatable color mixing. That matters.

Second, paper weight. The safe entry point for wet media is 120 gsm (about 80 lb text). Below that, Liquitex paint markers will buckle almost any paper. We order 100 lb cover stock (around 270 gsm) for the marker station, and the difference is dramatic — no bleed-through, no curl. Check the gsm before you order, not after.

The varnish bloom also showed up when we scanned the paintings for the gallery catalog — at the 300 DPI print standard we use for reproduction, those white patches were impossible to miss. Cleanup took another 40 minutes per image. It was a reminder that mistakes in the studio follow you into reproduction.

One more thing: Liquitex's professional line is cadmium-free in the colors we use, which simplifies our classroom ventilation protocols. A quiet advantage that doesn't show up on a spec sheet.

Where I'd Push Back on My Own Advice

Not every painting needs varnish. Not every marker purchase needs to be professional grade.

Skip the varnish when: the piece is a study, a practice exercise, or anything that won't leave the classroom. Dust it and move on. The $1,200 disaster happened because we varnished everything by default. Now we ask: is this piece going through a show, a storage room, and a parent's car? If no, varnish is optional.

Consider budget markers when: the goal is process, not product. Practice sketches, layout work, learning exercises — a budget set is fine. Liquitex paint markers earn their price when the work has to last, and when batch consistency matters for the lesson.

The waterproof caveat: on properly prepared rigid surfaces — primed wood with sealed backs, or non-absorbent panels — a cured painting with quality varnish handles water exposure impressively well. But "well" isn't "yes," and I've never fully understood why art teachers keep telling parents it is. A little honesty in February saves a lot of disappointment in May.