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Tuesday, February 24, 2015

Visiting Australia

February 15-18, 2015, Paul Crawford (Business Director - Asia) and I visited our agent in Australia, IDM Instruments.  IDM Instruments was established in 1972. It is a privately owned company, that prides itself with an outstanding reputation as Australia's leading supplier of testing and measuring equipment.  This includes working with various companies in foam, packaging, paper, plastics and automotive industries.
Tommy Halmos (IDM) & Todd Popson (Technidyne)
President, Mr. Tommy Halmos, led our discussion with the staff of IDM.  We discussed Technidyne's new products the Color Touch X and TEST/Plus.  We also looked at the resources of IDM and plans for the future.  Tommy, Paul and I also made customer visits to several paper and packaging companies throughout Australia. Technidyne has worked with IDM in Australia for over 10 years.  The relationship allows customers in Australia to use the latest technology in the Paper Industry with extremely good, local technical support and service.

Thanks to the people of IDM Instruments for their continued good work, hospitality and professionalism.

Tuesday, February 17, 2015

New TAPPI Brightness Calibration Standards Format

For over 50 years, TAPPI optical calibration has been performed using small 1.5 inch X 2 inch paper 'tabs'.  Technidyne is issuing a new format that will consist of a tablet which is easier to handle and will provide more consistent data since the measurements will come from the same sheet of paper. In past, it was possible that the tabs were each from a different sheet of paper.

Technidyne customers who subscribe to TAPPI brightness and/or color standards will be receiving standards in this new format in March 2015.  

Here are links to two videos showing the use of the new calibration standards with the

Brightimeter Micro S-5


Brightimeter S-4M

These can be found on our Technidyne YouTube Channel.

When using the new standards format it is important that the standards not be dragged or slid across the instrument sample plate and aperture. This can damage the surface of the standards.

Please let us know if you have comments or ideas on how these will be best implemented. Contact our Lab Manager, Nick Riggs.

Monday, February 16, 2015

Paper Roughness (Smoothness) - The Printing Process

The Printing Process:One of the most important reasons for measuring and controlling surface smoothness is for print quality. For the contacting-type printing processes, the ink film will transfer to a paper surface upon physical contact. When the voids in the paper surface are deep enough prevent such contact, ink will not transfer to the low spots, and non-uniform ink transfer causes poor print quality. When the ink film is adjusted to achieve satisfactory print density on the rough areas of a web, the same ink film may be too heavy to achieve optimum print quality on the smoother portions, perhaps causing mottle and other problems.

Xerography Processes:
There are many reasons why the manufacturers of photocopy machines have target ranges for Sheffield roughness. A xerographic machine needs optimum paper surface properties for reliable sheet feeding, image transfer, and image fix. The fix level decreases as the Sheffield roughness increases, as it affects toner adhesion. Print density loss is observed as roughness increases. There also can be image problems with papers that are too smooth. Toner particles can be flattened and appear as larger dots, thus increasing the perception of the background. Rougher papers produce less background. With regards to paper handling, smoother papers are less stiff for a given basis weight. Smoother papers increase “electrostatic tacking” in the image transfer process. The coefficient of friction decreases with increasing roughness, a factor that is important in sheet transfer operations. The Sheffield roughness properties are carefully specified for the
electrostatic copier printing process.
Inkjet printing:
Similar to the photocopy machines, inkjet printers have paper handling requirements. The method in which a single sheet is transferred from the supply stack generally relies upon the friction differences in paper-to-rubber versus paper-to-paper in a stack. In recent years, there has been development work on optimizing 2-sided surface roughness for ink jet printers. The printing surface was manufactured to be smooth for image quality and the back side was rough in order to facilitate paper feeding and also to avoid excessive contact with a freshly-printed surface as printed sheets are successively stacked in the printer tray.

Related posts include information on the relationship between paper roughness (smoothness) and the following items:
  • Papermaking Process
  • Printing processes
  • Formation
  • Parker Print Surf Test
  • Sheffield Test
  • Applications

Thursday, February 12, 2015

Two New ISO Standards for Tissue Measurement

ANSI (American National Standards Institute) has just announced that two new optical standards have been published by ISO TC 6 (pulp, paper and paperboard) for the measurement of tissue.

ISO12625-15:2015  Tissue paper and tissue products -- Part 15: Determination of optical properties -- Measurement of brightness and colour with C/2° (indoor daylight) illuminant

ISO12625-16:2015  Tissue paper and tissue products -- Part 16: Determination of optical properties -- Opacity (paper backing) -- Diffuse reflectance method 

These standards have taken a while to be resolved. Experts from the United States and Canada have worked very hard to have these standards accepted by ISO since they are common measurements for tissue products in North America.  There was another standard that passed through the ISO system quickly due to partisan support of many European Experts.  The addition of Opacity and optical properties with UV Level C were added to complete the standards which reflect the practices and trade requirements of the entire worldwide Paper Industry.

ISO 12625-7:2014 Tissue paper and tissue products -- Part 7: Determination of optical properties -- Measurement of brightness and colour with D65/10° (outdoor daylight)

Monday, February 9, 2015

Basics of Spectral Reflectance

In 1666, Sir Isaac Newton observed that white light is made up of the spectrum of colors. Therefore, giving us the understanding of the Additive Color Mixing. That is when you combine primary lights (blue, green and red) in their highest intensity and equal amounts this results in white light.

When looking at spectral reflectance curves produced from different objects, it can be seen that:

White is 100% reflectance at all visible wavelengths from 400 to 700 nm.

Black is 0% reflectance at all visible wavelengths from 400 to 700 nm.

Therefore, "straight lines" with equal reflectance at all visible wavelengths from 400 to 700 nm are shades of gray. If the reflectance is nearer to 100%, this is a light gray. Likewise, if the reflectance is nearer to 0%, this is a darker gray.

Not until there is deviation from this "straight line" do we see various colors.

Blue reflectance curve

Here we see a blue reflectance curve. It has reflectance in the blue region of the spectrum (400-500 nm) and very little or no reflectance in the green (500-600 nm) and red (600-700 nm) regions of the spectrum.

Green reflectance curve

Here we see a green reflectance curve. It has reflectance in the green region of the spectrum, but very little or no reflectance in the blue and red regions of the spectrum.