Select rutile TiO₂ by the cost per square metre of a finished paint that meets the required dry hiding, shade, finish and film performance. For white waterborne acrylic or styrene-acrylic interior paints, first shortlist grades intended for the formulation’s finish and pigment volume concentration. Then compare replacement behavior in the existing recipe and optimize suitable candidates. Calculate the full formulation cost and the spreading rate that meets all acceptance conditions. A lower powder price or lower TiO₂ loading establishes a saving only when that calculation and representative application trials support it.

Shortlist Grades for the Required Finish

Define the dry contrast-ratio target, white shade, gloss or sheen, minimum film build, and relevant scrub and water-resistance requirements before testing. A high-PVC flat wall paint and a washable satin paint should have separate shortlists and acceptance conditions.

Pigment volume concentration (PVC) is the dry volume of pigments and extenders divided by their combined volume with dry binder. Above the critical PVC, insufficient binder leaves interparticle voids. Air can contribute to dry hiding, while the resulting structure can affect film integrity. TiO₂ particle spacing also matters: closely spaced particles can scatter less efficiently, so increasing TiO₂ does not necessarily increase hiding proportionally. The original study by Raghavendra and Shreepathi discusses these mechanisms in high-PVC waterborne paints.

Commercial grades address different formulation priorities. Two published examples illustrate why TiO₂ content alone cannot rank them:

These are manufacturer design descriptions, not comparative test results or ChemicalCell supply claims. They do not establish a winner between the grades. www.tronox.com

A lower TiO₂ percentage can reflect more surface treatment. Its suitability depends on the coating task. The treatment and particle characteristics affect how the pigment interacts with dispersant and binder; “rutile” alone does not specify that behavior. Powder whiteness and relative tinting strength also cannot replace dry hiding measurements in the intended paint.

Both cited data sheets note that particle-size results depend on measurement technique. Compare particle-size values only with their preparation and measurement methods identified.

Distinguish Replacement Performance from Formulation Improvement

Test the Existing Recipe First

Replace the reference with the same mass of commercial pigment powder. Keep other ingredient quantities, addition sequence, equipment, batch geometry and processing conditions fixed.

This trial answers whether the candidate works under the existing recipe. Equal powder mass can introduce different TiO₂ amounts, treatment levels and pigment volumes. Calculate the resulting TiO₂ content and PVC; use particle density rather than powder bulk density for volume calculations.

Record incorporation behavior, processing time, temperature, pH, viscosity and dry optical performance. Equal nominal PVC does not establish equal proximity to critical PVC when packing and binder demand differ.

Optimize Without Losing the Reference

Evaluate promising candidates through controlled changes to dispersant level or processing. Keep binder solids and extender composition fixed initially, then document any further formulation changes.

BYK’s technical overview of dispersing additives for aqueous systems explains that dispersion and stabilization can influence hiding and viscosity. It also identifies water resistance as a consideration for hydrophilic additives. Record dispersant dosage on both an as-supplied and active basis, and include its cost.

If a revised dispersant package improves the candidate, test that package with the reference pigment where technically appropriate. This comparison helps determine whether the benefit depends on the new grade, the revised formulation, or their combination.

Without that control, the economic conclusion applies to the formulation package. An ingredient change that benefits both grades may offer a useful reformulation opportunity without requiring a pigment substitution.

Compare Dry Hiding at Controlled Film Build

Use a defined black-and-white substrate comparison:

Contrast ratio = Y over black / Y over white

Y is the measured luminous reflectance factor under the selected measurement conditions. A ratio closer to 1 indicates less visible substrate contrast.

Datacolor’s opacity-measurement training material expresses contrast ratio as Y over black divided by Y over white, multiplied by 100. This guide uses the equivalent 0–1 ratio: 0.98 corresponds to 98%.

ISO 6504-3:2019 addresses hiding measurements for white and light-coloured paints for masonry, concrete and interior use. Select an applicable procedure and follow the full standard when claiming conformity. The comparison outline below does not replace it.

Measure both:

• Contrast ratio at matched dry-film thickness, to compare the formulations at the same film build.
• Spreading rate at the agreed acceptance conditions, in m²/L of finished paint, to establish how much acceptable area a litre can cover.

Use several film builds that bracket the hiding target. Document deposited quantity or film thickness using a suitable method, together with volume solids, substrate, conditioning and measurement settings. An identical applicator gap does not guarantee identical dry-film thickness.

Repeat preparations and measurements sufficiently to establish variability. A thick film near complete opacity may hide differences between grades, and a small contrast-ratio increase cannot be converted directly into the same percentage of paint savings.

The acceptable spreading rate must also meet minimum film build, shade, finish and relevant film-performance requirements. Hiding alone cannot set the economic application rate.

Trace Pigment Price and Loading into Paint Cost

Calculate cost from the complete wet formulation:

Raw-material cost per kg of paint = Σ(ingredient mass fraction × delivered ingredient price per kg)

Then:

Raw-material cost per litre = raw-material cost per kg × paint density in kg/L

Use the commercial pigment powder price and its as-supplied loading. Include water, binder, extenders, dispersants and every other ingredient in the mass balance. If the candidate requires reformulation, cost those changes explicitly.

An Arithmetic Illustration

All figures below are hypothetical. Grades A and B are unnamed calculation inputs and are unrelated to the commercial grades cited earlier. The table is not a proposed recipe or a report of measured performance.

Each wet batch totals 100 kg. The non-TiO₂ ingredients therefore total 80 kg for A and 82 kg for B. Of their assumed costs, USD 130 is unchanged; the remaining USD 10 for A and USD 17 for B represent the respective formulation balances, including any adjusted additives, binder, extenders or water.

For the arithmetic, assume both formulations meet an internal dry contrast-ratio target of at least 0.98 and the same shade, finish, minimum film-build and film-performance requirements at the stated rates. Those rates are assumed inputs, not experimental results.

B uses less pigment, yet its pigment cost and total formulation cost are higher. Its assumed spreading advantage produces the saving:

Paint-material cost per m² = raw-material cost per litre / acceptable spreading rate

Under these assumptions, B costs approximately 6.7% less per square metre. Its break-even spreading rate is:

8.0 × (2.94 / 2.80) = 8.4 m²/L

B must exceed 8.4 m²/L to offer a paint-material saving against A on this basis. If repeat measurements place B near that boundary, the evidence does not establish a reliable saving.

Confirm the Decision Under Application Conditions

Take the shortlisted formulations into a representative application trial and measure total litres consumed per accepted area:

Paint-material cost per accepted m² = paint cost per litre × total litres consumed / accepted area

Consumption should include relevant application losses and rework. Do not add a second loss allowance for material already counted. Record coat count and labour separately; laboratory hiding results do not establish that an application coat can be removed.

The illustration covers raw materials only. Add documented differences in manufacturing cost when processing time, energy or yield changes, using the same accounting basis for both formulations.

Before routine substitution, confirm that the comparison remains acceptable after relevant storage and across representative pigment lots. Retain the reference when the candidate’s advantage disappears within normal variation or depends on compromising film performance.

ChemicalCell’s Pigments category provides an initial browsing route. Confirm the exact coating grade and supporting data before treating a listed material as a candidate.

For the selection decision, bring together the grade identity, complete costed formulation, acceptable spreading rate and representative application consumption. Approve the formulation package when these records support a repeatable saving while preserving the required coating performance.