My New Liquid Dye Seems Much More Concentrated Than the Previous Bottle — Should I Create a New Dosage Curve Rather Than Using My Old Formula?

First, confirm the new bottle really is stronger

Before you rewrite anything, rule out the explanations that have nothing to do with the dye lot. Liquid dyes can settle. The last third of an old bottle that sat for months unshaken may have been weaker or stronger than its first pour, so the lot you remember may not be the lot you last used. A new dropper can deliver bigger drops. And if you switched pack sizes, check the unit: CSI's own dye listings mix gm and ml sizes across colours, so a recipe written in millilitres and a new bottle dosed by weight are not automatically the same amount.

The clean test is a tint-strength comparison: the same small weight of old and new dye, each stirred into the same weight of uncoloured production wax, poured into identical containers and cooled together. Low doses reveal strength differences far better than deep shades, because a dark colour saturates and hides the gap. If you have no old dye left, use your retained reference candle or puck instead and accept that the comparison is less precise.

One scaling factor or a new dosage curve?

If the new lot is simply stronger, a single factor is tempting: use 60% of the old dose everywhere. That works only when the dye behaves the same way across your whole range of shades. In practice, colour depth does not rise in a straight line with dye dose. Pale shades respond sharply to small additions; deep shades flatten out as the wax approaches saturation. A stronger lot can move along that curve differently, especially if its tone is also slightly different.

So the honest answer to the title is: test whether one factor holds at the shades you actually sell. If it holds, use it. If it does not, build a short curve. Most makers who sell three depths of one colour need a curve; makers with one colour at one depth can usually get away with a factor.

There is also a production reason to prefer a curve with a strong dye. The smaller the dose, the larger the weighing error as a share of it. If the new lot needs roughly half the old amount, any slip on the scale now moves the shade twice as far. That is often the point at which a coloured wax masterbatch, dosed by weight, becomes worth the extra step.

What a dosage curve is here

A dosage curve is a small table, per dye lot, that says: to match my approved pale, medium and deep standards, this lot needs these weights per kilogram of wax. It is your own internal record, validated on your wax. CSI does not publish dye concentration or a dosage per kilogram for any dye, so there is no supplier curve to copy.

Worked example: three depths of one blue

You sell a pale, a medium and a deep blue in CSI 468 coconut-soy. Your old formula, expressed in parts of dye per kilogram of wax, was 1 part, 3 parts and 8 parts. You pour a ladder of the new lot around each standard, cool the pucks together, and find the matching dose for each.

The ratio drifts from 0.55 to 0.80. If you had applied the medium factor of 0.60 to the deep shade, you would have dosed 8 × 0.60 = 4.8 parts instead of the 6.4 parts that matched, and your deep blue would have come out visibly light. That is the case for a curve: three measured points, not one factor stretched across the range.

Now weigh the effort. A ladder of five pucks around each of three standards is fifteen pucks. At a suggested starting point of 40 g each, that is 600 g of wax. CSI 468 at ₹650.00 per kg makes that 0.6 × ₹650.00 = ₹390.00, or less if you buy the 5 kg pack at ₹3,185.00, which is ₹3,185.00 ÷ 5 = ₹637.00 per kg, giving 0.6 × ₹637.00 = ₹382.20. An afternoon and under ₹400 of wax buys a curve you will use for the whole life of the bottle.

How to build the curve without wasting a day

When to accept, when to hold, when to send it back

A much stronger lot is not a defect in itself. It becomes a problem only if you dose it by the old formula. Where it matters for the supplier is consistency: if every bottle you buy lands somewhere different, the cost is in repeated curves, not in the dye.

For a CSI dye, message the colour, pack size, invoice number and photos of your cooled ladder on WhatsApp (+91 7397976926), ask whether anything changed, and file the reply with the curve. If the explanation does not satisfy you and your shades cannot be matched, the lot does not go into production, even when it came from us.

What to write down so the next bottle is faster

There is one more thing a record protects you from: an over-correction. If the next bottle drifts back towards the original strength and you are still dosing by the reduced curve, every candle comes out pale. Checking the tint strength of each new bottle against the last approved lot, not against the first one you ever bought, catches that swing before it reaches a customer.

Keep a one-page dye record per colour: each lot received, the date, the tint-strength result against the previous lot, the matched doses, and who approved it. After three or four bottles you will know how much this colour tends to move between lots, and your ladder can shrink to two or three points around the expected match. That is how a curve pays for itself: the second time is quicker than the first.

Where this page fits

CSI already has guides that cover parts of this question. This page covers the goods-in check for the question above; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions