Curable vs. Non-Curable Reducer

This week’s tip was inspired by a conversation I had at Print Hustlers 2025 with Sam from Branded Threads. He asked, “What’s the difference between Curable and Non-Curable Reducer?”

This is an EXCELLENT question that everyone in the print community should understand!

I just answered a tech email from a guy trying to find the perfect white to print in a single stroke. (We’ll talk about the farcical quest to find a “single-stroke white” and why that’s nonsense in another article.) This printer was adding Fashion Soft and 3% Non-Curable Reducer to his whites and was disappointed to find his prints cracking.

First off—without getting too far into the weeds—any white ink from Avient should not need any additives. It only needs to be pre-sheared, as I discussed in my previous article, “Why Pre-Shearing Your Plastisol Ink Is Essential for Better Prints.”

But back to Sam’s question: Curable reducers, extenders, Fashion Soft Base, Chino Base, and Soft Hand Base are all curable. They can either be tinted with colors or added to colors to create a softer hand, adjust tone for sepia or vintage effects, or produce subdued, distressed prints.

Fashion Soft Base is more of a specialty product, designed to create a super-soft hand that imitates water-based prints. It will not hold down fibers. First-time users may think the ink has washed off after laundering—when in fact, the soft fibers of the garment are simply showing through the print, much like a soft-base water-based print.

Use it as an additive to PC Base plus pigments to achieve a super-soft feel similar to water-base printing, or add it to finished inks for a softer hand—up to 70% by weight.

Chino Base is Rutland’s counterpart to Fashion Soft Base but offers slightly more opacity on its own. That added opacity helps retain more color density and minimizes tonal loss when extending inks. Use to create a “worn and washed” effect. It can also be printed on it’s own to create a “Tone-on-Tone” effect on darker color garments. Works as a curable reducer.

Soft Hand Base is a softer version of an extender base but isn’t suitable for darker garments. It’s used to make ink more translucent and softer on lighter garments—similar to Union’s classic Halftone Base product. Add until you get the desired effect. It can be mixed in at any ratio but reduces the opacity and color strength. This base will diminish the gloss of the ink it’s mixed into.

Extender Base is a general term, similar to products like SHAPE, or Finesse for everyday inks. These allow you to extend your ink, effectively increasing your print yield per gallon by reducing the concentration of the color base—helping you save money while maintaining print quality.

Primer Clear can be printed as a first down to lock down fibers and control fibrillation. This can also be used to reduce opacity, Mix with opaque colors to reduce cost when printing on lighter colored garments.

Viscosity Buster / Non-Curable Reducer is used to improve the flow of inks that may have thickened or “bodied up” over time. Use 1–3%. Any more than 3% will affect cure. On the low end, use it to optimize flow; on the high end, use it to revive old, cakey, or dried buckets of ink.

For example, if you bought out a shop’s inventory of old plastisol inks that were stored with lids off and have cracked or dried out, you could use Viscosity Buster to reintroduce the plasticizer that has evaporated over time. Viscosity Buster (Non-Curable Reducer) is simply plasticizer.

Plasticizer and resin combine during the curing process to form the ink film—they cannot cure properly without each other. If you upset the balance by overloading an ink with plasticizer it will not cure.

Be careful when adding Viscosity Buster. I usually advise starting with 0.5% by weight and not exceeding 2%, reserving 3% for worst-case scenarios.

You can also use Non-Curable Reducer to perform a dye-migration test, as described on The Ink Kitchen website and article.

Be sure to explain this to everyone on the print floor, and consider storing Non-Curable Reducer / Viscosity Buster away from your ink-mixing area so that no one innocently adds it “willy-nilly” to improve flow. A gallon of this product will normally last for years. Lock it up in a cabinet and clearly label any ink you’ve added it to with the percentage used. That way, your printers know not to add more Viscosity Buster to those inks that already contain it.