Paper Marbling Coverage Calculator
Marbling medium and paint volume from paper size.
About this calculator
Paper marbling — floating carrageenan-thickened water in a tray, dropping paint onto the surface, then laying paper down to lift the pattern — needs three supplies sized to your tray and sheet count, which is what this calculator works out. Solution volume per fill is simply tray length × width × your chosen solution depth (converted from cm³ to liters), and carrageenan powder is dosed at the standard ratio of about one tablespoon (8g) per liter of that solution. Because the size bath degrades with use, the calculator assumes a fixed 30 sheets per fill before it needs refreshing, so total sheets requested divides into that to determine how many tray refills — and how much total solution and carrageenan — the whole session will consume. Alum, used to pre-treat (mordant) paper so paint adheres properly, is calculated separately from a rule of thumb of one liter of soak solution per 10 sheets at 30g of alum per liter, rounded up to whole batches.
Paint volume assumes a flat 1 ml per color per sheet, a reasonable average for typical marbling drop counts, multiplied across your sheet count and number of colors. The maximum paper size simply subtracts a 1cm margin from each tray dimension so the paper won't drag against the tray walls. Two default numbers here are worth double-checking against your own setup — the assumed 30-sheet bath lifespan and the 1ml-per-color-per-sheet paint estimate — both vary in practice with your specific paints, drop technique, and how contaminated you let the bath get before refreshing, so treat these as a shopping-list starting point rather than an exact budget.
Inputs
Results
Solution per fill (liters)
3.6
Total solution needed (liters)
3.6
How to Use This Calculator
- Enter the internal length and width of your marbling tray in centimeters.
- Set the depth of carrageenan or size solution in the tray — typically 2–4 cm.
- Enter the total number of sheets you plan to marble in this session.
- Enter the number of paint or ink colors you will use on each sheet.
- Read the solution volume in liters and carrageenan grams needed per tray fill, plus total solution required.
- Use the alum grams output to pre-treat your paper for proper paint adhesion before marbling.
How the result changes with Tray length (cm)
| Tray length (cm) | Solution per fill (liters) | Total solution needed (liters) |
|---|---|---|
| 20 | 1.8 | 1.8 |
| 30 | 2.7 | 2.7 |
| 60 | 5.4 | 5.4 |
| 100 | 9 | 9 |
What each input means
- Tray length (cm)
- Internal length of your marbling tray in centimeters.
- Tray width (cm)
- Internal width of your marbling tray in centimeters.
- Solution depth (cm)
- Depth of carrageenan/size solution in the tray. Typically 2-4 cm.
- Number of sheets to marble
- Total sheets of paper you plan to marble.
- Number of paint colors
- Number of different paint/ink colors used per sheet.
What each result means
- Solution per fill (liters)
- Volume of carrageenan/size solution needed per tray fill.
- Total solution needed (liters)
- Total solution including tray refills.
- Carrageenan per fill (g)
- Grams of carrageenan powder per tray fill.
- Alum for mordanting (g)
- Grams of alum (potassium aluminum sulfate) for paper pre-treatment.
- Total paint needed (ml)
- Total volume of marbling paint/ink across all colors and sheets.
- Paint per color (ml)
- Volume of each paint color needed for all sheets.
- Tray refills needed
- Number of times you will need to refresh the size bath.
- Max paper size (cm)
- Largest square paper that fits in the tray with 1 cm margins.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersTray length (cm) = 40, Tray width (cm) = 30, Solution depth (cm) = 3, Number of sheets to marble = 20 = 5 input(s) provided
- Calculate Solution per fillSolution per fill = solutionVolumeMl / 10003.6 = 3.6
- Calculate Total solution neededTotal solution needed = solutionVolumeLiters * trayRefills3.6 = 3.6
- Calculate Carrageenan per fillCarrageenan per fill = solutionVolumeLiters * 828.8 = 28.8
- Calculate Alum for mordantingAlum for mordanting = alumSoakLiters * 3060 = 60
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does increasing my sheet count raise tray refills instead of just more paint?
The size bath is modeled as degrading after a fixed 30 sheets, so trayRefills is ceil(numSheets / 30) — once you cross that threshold the calculator assumes you'll refresh the solution, which multiplies both the solution volume and carrageenan needed by however many refills that requires. Paint, by contrast, scales linearly with sheets regardless of refills, since paint is consumed per sheet rather than degrading the bath itself.
Why is the alum calculation independent of tray size?
Alum mordants the paper itself, not the marbling bath, so it's calculated from a dip-solution ratio of one liter per 10 sheets at 30g of alum per liter — a function purely of how many sheets you're treating, rounded up to whole liters. Tray dimensions only affect the carrageenan size solution the paper floats on, which is why the two supplies are computed from completely separate inputs.
Is the carrageenan dosage exact for my specific brand?
No — the calculator uses a common ratio of about one tablespoon (8g) per liter of water, which works for typical culinary-grade carrageenan powders used in marbling, but different brands and particle sizes can need slightly more or less to reach the right viscosity. Mix a small test batch first and check that paint drops spread and hold their shape properly before committing to the full calculated amount.
How is the maximum paper size determined?
It simply subtracts a 1cm margin from both the tray's length and width (maxPaperLength = trayLengthCm − 2, and the same for width), then reports the smaller of the two as the largest square sheet that fits. That margin exists so the paper doesn't drag against or catch on the tray walls when you lay it onto the floating pattern.
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