Reactive Print Batch Losing Shade and Fastness Mid-Order
A screen-printing unit in Cuttack has taken an order for 500 cotton voile dupattas (100 cm × 200 cm) for a festival buyer, printed with reactive dyes. After the first 100 pieces the shade becomes noticeably lighter and duller, motifs show colour haloes wicking 2–3 mm beyond the screen edge, and dry rubbing fastness on the latest pieces is only grade 3. The printer had to stop at midday and mix fresh paste because, as the helper said, 'the colour was dying in the screen'. The voile arrived in two lots; the second lot was not desized. Steaming was done for 25 minutes in an open chamber, although the unit's own standard is 45 minutes at 102 °C. Four hundred pieces remain to be printed, the buyer's deadline is 12 days away, and the unit has already been paid a 30% advance.
1. Rank the likely causes of the three symptoms and state the evidence you would collect.
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Four causes, ranked.
- Paste hydrolysis - most likely for the shade drift. Reactive paste with alkali has a pot life of only a few hours; a midday re-mix to 'revive colour' is a classic sign. Once hydrolysed, the dye cannot bond, so shade drops and unfixed dye raises crocking, matching the grade 3 rub result.
- Thickener viscosity loss - most likely for the haloes. A thin paste bleeds under the screen, giving 2–3 mm wicking. Check stock paste viscosity and squeegee angle and pressure.
- Inadequate steaming - 25 minutes in an open chamber at 102 °C is below the unit's own 45-minute standard; poor fixation explains both dullness and low fastness.
- Fabric variation - the undesized second lot carries a size-loaded, hydrophobic surface, so paste sits on top and gives patchy penetration and a lighter shade.
Evidence: retained paste samples, viscosity readings, lot numbers of both fabric lots, the steaming log, and laboratory wash and rub tests on pieces from the first and last fifty.
2. Prepare a corrective plan for the remaining 400 pieces that fits the 12-day deadline.
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Stop printing and fix the process, not the pieces.
Sort the remaining voile by lot; desize and scour the second lot (or return it), dry and cool before printing. Prepare paste in small batches of 40–50 pieces, add alkali last, keep the bucket shaded and discard after 4–6 hours, recording mix time on each batch. Standardise the thickener with a measured stock paste and check viscosity with a Ford cup at the start of each shift; set and lock squeegee pressure and angle. Print a three-piece strike-off per lot and stop if the shade is out. Steam properly: 45 minutes at 102 °C with saturated steam, then wash off thoroughly and dry.
With 12 days and 400 pieces, a realistic plan is 2 days for fabric preparation and strike-offs, 7 days printing at about 60 pieces a day, and 3 days for steaming, wash-off and finishing. Tell the buyer now and ask for a two-day extension rather than shipping doubtful goods.
3. Decide the fate of the 100 printed pieces and set out the quality records and buyer communication.
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The 100 pieces are not first quality: haloes and grade 3 rubbing fastness will not survive a festival wash, and the buyer will return them.
Options in order of preference: re-print them in a darker colourway if the halo can be hidden and fastness corrected - test first, do not assume; sell them to the buyer as a disclosed second-quality lot at a reduced price with the defect named in writing; or hold them as internal samples. Never mix them into the good lot.
Documentation: batch-wise shade card, paste batch record, steaming log, fabric lot numbers, wash and rub test results, and a signed deviation note from the buyer. Send a short written update with photographs within 24 hours stating the root cause, the corrective action and the revised delivery date. Returning the 30% advance or offering a small credit is cheaper than a rejected consignment and a damaged reputation in a small cluster.