Basic Black Dyes
Deep black on mechanical pulp needs a dye with real affinity for lignin, or the shade washes out into white water.
Buying support
Colour Selection And Shade Control
Picking basic or direct chemistry by furnish, then holding the shade batch to batch.
Start from the furnish, not the shade card
Basic dyes are cationic and have strong affinity for lignin-containing pulp - mechanical, semi-chemical and groundwood. Direct dyes are anionic and suit chemical-pulp and packaging furnish.
Pick the shade family
CHEMSUM carries basic black, brown, green, red, violet and yellow, and direct black, brown, orange, red and yellow.
Fix the dye so it stays in the sheet
A Fixing Agent binds anionic dyes and pigments to fibre, cutting dye loss into the white water and improving uniformity.
Control what the water loop gives back
Colour that accumulates in a closed loop comes back as shade drift. PolyDADMAC removes suspended solids and colour from the circuit.
Set brightness separately from shade
Optical Brightener Agents work on whiteness by re-emitting UV as visible blue light; they are a brightness tool, not a shade tool.
Products in play
What You Will Be Choosing Between
Direct Red Dyes
Red dye lost to white water is red dye paid for twice.
Fixing Agent
Dye and filler that do not fix on fibre end up in the white water loop as anionic trash.
PolyDADMAC
Anionic trash in a closed loop drags down retention and drainage at the same time.
Optical Brightener Agents
Brightness targets are set by the buyer, not the furnish.
Frequently Asked Questions
What does colour selection and shade control involve?
Picking basic or direct chemistry by furnish, then holding the shade batch to batch.
Which products are involved?
Basic Black Dyes, Direct Red Dyes, Fixing Agent, PolyDADMAC, Optical Brightener Agents.
Do you support the trial on the machine?
Send the grade, furnish and target and we will give a dosage starting point and the sequence to run. Technical questions go to the same WhatsApp thread.
Colour Selection And Shade Control
Send the grade and the target and we will walk the sequence with you.