Sigma is our very popular heatset web black for low-quality uncoated and newsprint stocks. Sigma delivers the smoothness, density, blue tone and low-linting of a more expensive heatset ink at nearly newsink cost! Sigma prints a dense, even, very flat, dull finish perfectly suited to rough uncoated and news stocks especially in the halftones. The vehicle system in Sigma is truly superior to common newsinks. Sigma can also be run without heat at high speeds, setting within minutes to a scuff and smear-resistant finish just like a heatset ink. As you can see, this makes Sigma a multi-purpose economy black for almost any web service on news-type papers. Sigma is also available in toned and in gelled versions as "Special Order" items. Check the chart below for different tack ratings.
Tack (1 min at 1200 RPM) |
Regular Version |
Toned Version (with 4% alkali blue)  |
Gelled Version |
Tack 6+ |
Sigma 1 |
Sigma 1 Modified |
Sigma 1 G |
Tack 6 |
Sigma 2 |
Sigma 2 Modified |
Sigma 2 G |
Tack 5+ |
Sigma 3 |
Sigma 3 Modified |
Sigma 3 G |
Tack 5 |
Sigma 4 |
Sigma 4 Modified |
Sigma 4 G |
Tack 4 |
Sigma 5 |
Sigma 5 Modified |
Sigma 5 G |
Sigma "G" Series Gelled Heatset
Blacks
A special family of gelled Sigma blacks is available. The gel modification is particularly useful for older presses that have problem ink trains prone to spitting, misting, and waterlogging. Additionally, Sigma "G" series blacks are very convenient when the ink must be handled in buckets, since low-tack inks tend to be difficult to "knife" into the ink fountain. Sigma "G" series blacks are available as "Special Order" items.
Sigma "Mod" Series Toned Heatset
Blacks
A toned version called Sigma "Mod" black is offered for customers who want extremely blue halftones along with Sigma's famous flat, dense look on newsprint stocks. The Sigma "Mod" blacks all have approximately 4% of Alkali Blue flush added to them. Halftone density is excelent on news stocks, and the tone is quite blue. Sigma "Mod" series blacks are available as "Special Order" items.
