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Monday, March 31, 2014

Ranking Tissue Softness

Tissue softness and optical properties such as brightness and color share similar characteristics. Many years ago, most considered the best tool for evaluating optical properties to be the human eye. Modern tools like the spectrophotometer today help us quantify what the human eye perceives. For tissue, the human hand has long been considered the best tool for determining tissue softness. The difficult reality is that any subjective evaluation creates uncertainty and uncertainty leads to variation. Variation is the enemy of consistency and quality.

Simply put, the Emtec Tissue Softness Analyser (TSA) is a tool that quantifies the otherwise subjective hand feel or “softness” evaluation of tissue.

Many aspects of tissue production have long been considered “art” rather than science. The subjective nature of hand feel is a perfect example. Anyone can rank order tissue samples in order of perceived softness, but can you get a group of people (especially papermakers) to agree? The Emtec Tissue Softness Analyser (TSA) quantifies different components associated with “hand feel” or softness perception into a single numerical value that can be used as an indication of “tissue softness.”

Why is the TSA beneficial?

1.   The TSA is fast and easy to use. Anyone can learn to use the TSA to determine a measurement value indicative of tissue softness. That measure is the tissue softness index.

2.   With quantified measurements, process parameters such as crepe or furnish can be optimized to improve softness.

3.   With a measurement tool, benchmarking becomes easier. The attached graph illustrates benchmark results for several different retail brands of bath tissue.

4.   With the TSA, customer feedback or feedback from “Hand Feel” panels can be quantified, and from that feedback, product specifications are improved.

With meaningful product specifications, I have historically seen more stable production. Stability and consistency are hallmarks of higher quality. If you want to improve the quality of your tissue products, try the Emtec TSA or consider sending in samples of your current tissue. You can see at any point in time, quickly how your current tissue compares to your competitors.

Monday, March 24, 2014

Paper Machine Control Strategies: Color Matching (Part 2)

There are predominantly two approaches to color control in the Paper Industry.

The second approach is to control color separately and fluorescence simultaneously.  This method includes ultraviolet (UV) light from the light source for controlling color as well as fluorescence.  This mingling of the affects of optical brighteners with the affects of the dyes is then used to match the standard.Pros and cons:

When pulp brightness is especially good or other variables help increase the sheet brightness, less optical brighteners can be used and this helps lower costs.

This method leads to metamerism even from the same machine in the same mill, as different optical brightener levels lead to a very different looking sheet under different lighting conditions.  The control strategy is also more complex - with a three-dye system there are 13 variables to control.

Control variables for Grade 1 using the UV included measurements
to control Color and Fluorescence

Dye 1
Dye 2
Dye 3
variable 1
variable 2
variable 3
variable 4
variable 5
variable 6
variable 7
variable 8
variable 9
variable 10
variable 11
variable 12
Fluorescent component

variable 13

Part 1 of this discussion on approaches to control color in the Paper Industry revolves around controlling color and fluorescence separately.

If you have questions or comments, please contact me at