Quick answer: For most pours, add about 1 to 2 parts pouring medium to 1 part acrylic paint. Use roughly 1:1 for thin craft paints, 1:1.5 for soft-body artist acrylics and 1:2 or more for heavy-body paint, then add water a few drops at a time until the mix flows like warm honey. Always check the medium’s label, because some brands are formulated for different ratios.
Getting the ratio wrong is behind most failed pours. Too little medium and the paint drags, stalls and cracks as it dries. Too much water instead of medium and colors turn weak, chalky and fragile. Knowing how much pouring medium to add to acrylic paint is less about one magic number and more about matching the ratio to the paint you are using.
This guide gives starting ratios for every common paint type, explains how to test consistency, and shows how to adjust for different pour techniques, canvas sizes and conditions.
Why the Ratio Matters
Acrylic paint is pigment held in an acrylic binder. When you thin it heavily with water alone, the binder becomes too dilute to form a strong film. The result can be crazing, cracking, poor adhesion or a dusty surface. Pouring medium thins the paint for flow while adding more binder, so the dried layer stays intact.
Mediums are not all the same thickness, which is why ratios vary between products; our guide to the leading acrylic pouring mediums and how they handle compares several. Whatever you use, the ratio controls three things:
- Flow: how easily paint moves and levels across the surface.
- Color strength: more medium spreads pigment further and makes color more transparent.
- Film strength: enough binder prevents cracks and peeling.
How Much Pouring Medium to Add to Acrylic Paint: Starting Ratios
| Paint type | Paint : pouring medium | Water | Notes |
|---|---|---|---|
| Craft acrylic (bottles) | 1 : 1 | Little or none | Already thin; too much medium weakens color |
| Soft-body artist acrylic | 1 : 1.5 | Small amount | Balanced default for many pourers |
| Fluid acrylic | 1 : 1 | Minimal | Very pigmented and thin to begin with |
| Heavy-body acrylic | 1 : 2 to 1 : 3 | Moderate | Needs more medium and some water to loosen |
| Metallic and interference paint | 1 : 1 to 1 : 1.5 | Small amount | Too much medium can dull the sparkle |
| White (base layer) | 1 : 1.5 to 1 : 2 | Slightly more | Slightly thinner base helps colors move |
These are starting points. Brands differ in thickness and pigment load, and pouring mediums differ in viscosity. If the medium’s label recommends a specific range, start there.
How to Use Acrylic Pouring Medium: Mixing Step by Step
- Measure by volume. Use graduated cups or a syringe for accuracy. “Eyeballing” makes it hard to repeat a successful pour.
- Add paint first. Squeeze 1 part paint into a clean cup.
- Add medium. Add the amount from the table above.
- Stir slowly for two to three minutes. Scrape the bottom and sides so no clumps remain. Slow stirring traps fewer bubbles.
- Test the flow. Use the drip test described below.
- Adjust with water. Add water in very small amounts, about half a teaspoon at a time for a few ounces of paint, stirring after each addition.
- Rest. Let mixed cups sit for 5 to 15 minutes so air bubbles rise.
- Record your recipe. Write down paint, medium, ratio and water for every color you like.
The Drip Test: Your Best Consistency Check
Numbers get you close; the drip test confirms it. Lift your stir stick a few inches above the cup and watch the stream.
- Too thick: paint drops in blobs, piles up and stays as a mound for several seconds.
- Just right: a smooth, unbroken stream that forms a small mound and sinks back into the surface in about two seconds.
- Too thin: paint runs like water and disappears instantly, often with a watery edge.
Many pourers describe the right consistency as warm honey or slightly thinned cream. Some like it a bit thinner for big, sweeping lacing and a bit thicker for dirty pours that keep more defined colors.
Adjusting the Ratio for Different Pour Techniques
| Technique | Consistency | Ratio tendency |
|---|---|---|
| Flip cup / dirty pour | Warm honey | Standard ratios |
| Swipe | Slightly thicker colors, thinner base | Less water in colors, more in base |
| Dutch pour (air blown) | Thinner | More medium and a little more water |
| Ring or tree ring pour | Slightly thicker | Standard ratio, minimal water |
| Puddle or bloom pour | Thinner, very smooth | Higher medium ratio |
| String pull | Medium-thick | Standard ratio, little water |
How Much Mixed Paint Do You Need?
Running out halfway through a tilt leaves bare corners. A rough guide many pourers use is about 1 ounce of mixed paint per 16 square inches of surface for a flat pour, plus extra for edges and runoff.
| Canvas size | Approx. mixed paint |
|---|---|
| 8 x 10 in | 5–6 oz |
| 11 x 14 in | 9–10 oz |
| 12 x 12 in | 9–10 oz |
| 16 x 20 in | 20–22 oz |
| 24 x 36 in | 50–55 oz |
Deeper canvases with painted sides need more. If in doubt, mix a little extra; spare paint can go into a small panel or test card.
How to Use Liquitex and Apple Barrel Pouring Mediums
Branded mediums each come with their own guidance, and it is worth following it. Some artist-grade mediums are fairly thick and designed to be mixed at around 1 part paint to 2 parts medium, sometimes more. Some craft-brand mediums are thinner and designed to pair with that brand’s craft paint at roughly equal parts. The safest approach is to start with the label ratio, then fine-tune with the drip test.
If you are still choosing a medium, ratios are one of the details our roundup of the best pouring medium for acrylic paint compares, alongside finish, flow and cell behavior.
Adding Silicone and Other Additives
Additives change consistency slightly, so factor them in after the main ratio is set. Silicone oil for cells is used in tiny amounts, often one or two drops per few ounces of paint, and stirred in only briefly so it stays in small droplets. Adding it before you finish adjusting consistency makes it hard to judge the drip test. Some pourers add a small splash of isopropyl alcohol for cell effects; it thins the paint a little, so check consistency again afterward. Mix the paint, medium and water first, then add any cell additive last.
Where Water Fits In
Water is the fine-tuning tool, not the main thinner. A common guideline is to keep added water small, often well under a quarter of the total mix, so the binder stays strong. If you find yourself pouring in lots of water to get the paint moving, add more medium instead.
Use distilled water if your tap water is very hard or contains a lot of minerals, as it can occasionally affect mixing and finish.
Sample Recipes to Start From
These example recipes show how the ratios translate into real cup amounts. Adjust each with the drip test.
Beginner flip cup on an 11×14 canvas (craft paint)
- White base: 2 oz paint + 2 oz medium + a few drops of water
- Three accent colors: 1 oz paint + 1 oz medium each
- Total: about 10 oz of mixed paint
Swipe on a 12×12 canvas (soft-body artist paint)
- Base color: 2 oz paint + 3 oz medium + about 1 teaspoon water
- Four accent colors: 0.5 oz paint + 0.75 oz medium each, little or no water
- Total: roughly 10 oz, with slightly thicker accents for crisp swipes
Dutch pour on a 16×20 canvas (heavy-body paint)
- Background: 3 oz paint + 6 oz medium + water to a thinner flow
- Three blowing colors: 1.5 oz paint + 3 oz medium each, thinned slightly
- Total: about 22 oz
Write down each successful version, including the brand of paint and medium, so you can repeat it later.
Signs Your Ratio Is Off
Cracks or crazing after drying
Often too much water, too little medium, or a very thick layer drying unevenly. Increase the medium ratio, reduce water and dry at room temperature away from fans.
Colors look washed out
Too much medium relative to paint. Add more paint or use a more pigmented paint.
Paint stalls and will not cover the canvas
Too thick. Add medium and a tiny amount of water, then repeat the drip test.
Colors bleed into mud
Often too thin, so colors mix as soon as they touch. Thicken slightly and tilt less.
Some colors sink and vanish
Heavier pigments, such as many whites and earth colors, can sink through lighter ones. Adjusting the ratio of each color so densities balance can help, as can a slightly thinner base.
Dimples or craters
Usually trapped air from fast stirring, or too much silicone. Stir slowly, rest cups, and reduce additives.
Balancing Ratios Across a Whole Palette
Each color in a pour is mixed separately, and each pigment behaves a little differently. Titanium white and many earth colors are dense and thick. Some transparent colors, such as phthalo blue, are very strong and can overpower a mix even in small amounts. Metallics often contain mica particles that settle quickly.
A practical way to balance them:
- Mix every color at your standard ratio first, for example 1 part paint to 1.5 parts medium.
- Line the cups up and drip test each one in turn.
- Adjust the outliers. Thicker colors get a little more medium or a few drops of water; runny ones get a little more paint.
- Make the base color, often white, slightly thinner than the rest so the accent colors can move through it.
- For very strong pigments, use less paint and more medium so they do not dominate the pour.
The aim is not identical ratios but matching consistency. Two colors at different ratios that drip the same will usually pour well together.
Effect of Temperature and Humidity
Conditions in the room change how the same ratio behaves. In a cold room, paint and medium are thicker, so you may need slightly more water to reach the same drip. In a warm, dry room, paint flows easily but skins over faster, which can cause crazing as the surface dries ahead of the layers beneath. High humidity slows drying and can leave the surface tacky for longer.
A comfortable room temperature, roughly 65 to 75 degrees Fahrenheit, with no fans or heaters blowing directly on the work is a sensible target. If you change rooms or seasons, repeat the drip test rather than trusting last month’s notes.
Measuring Tools That Make Ratios Easier
- Graduated plastic cups: marked in ounces or milliliters, inexpensive, and easy to read.
- Plastic syringes without needles: accurate for small amounts of water or silicone.
- A kitchen scale: some pourers measure by weight for even more consistency, especially for large batches.
- Squeeze bottles: handy for storing premixed medium so you can pour it cleanly.
Tips for Consistent Results
- Mix all colors for one pour at the same time so they share temperature and consistency.
- Bring paints and mediums to room temperature; cold paint is thicker.
- Use the same cup size for every batch so your volume estimates stay reliable.
- Keep a small notebook or phone note of every recipe that works.
- Stir again just before pouring; pigment can settle in mixed cups.
FAQs
What is the ratio of pouring medium to acrylic paint?
Start with 1 part paint to 1–2 parts pouring medium. Thin craft paints need less medium; heavy-body paints need more.
Can I use too much pouring medium?
Yes. Too much makes colors transparent and weak. It will not usually harm the film, but you may lose the color intensity you want.
Should I add water to pouring medium and paint?
Only small amounts for fine-tuning. Pouring medium should do most of the thinning so the paint film stays strong.
How do I know if my pouring paint is the right consistency?
Use the drip test. Paint drizzled from a stick should form a small mound that sinks back into the surface in about two seconds.
Do all colors need the same ratio?
Not always. Different pigments vary in thickness and density, so some colors may need a bit more or less medium to match the others.
How much pouring medium do I need for a 12×12 canvas?
About 9–10 ounces of mixed paint is a reasonable target, so roughly 4–6 ounces of medium depending on your ratio.
Final Thoughts
Start at 1 part paint to 1.5 parts medium, adjust for your paint type, and let the drip test have the final say. Measure, record and repeat what works, and your pours will become far more predictable. Choosing a medium that suits your paints makes ratios easier to hit; see our guide to pouring mediums that improve acrylic flow and finish to compare your options.
