#31 Tales from the Press Trial

On April 17th and 18th I had the pleasure of participating in a press trial with MacDermid Printing Solutions to evaluate the effectiveness of their new Stabil-X offset printing blanket. I am writing today about the TVI curve of the various trial conditions.

We ran five different conditions during the course of the trial. All the trials shown in the graph involved only one printing unit running magenta ink. The curves also represent the averaging of 10 press sheets. The five trial names and descriptions are:

• STX opt – Stabil-X blanket run at optimum packing level
• Press std – The set-up of the press when we arrived
• STX -.003 – Stabil-X purposely under packed by 3 thousandths
• STX +.002 – Stabil-X run at 2 thousandths over
• STX +.004 Stabil-X run at 4 thousandths over

As one might expect the STX -.003 has not only the lowest TVI, but also a very poorly formed curve. A pretty good example of why you do not want to run your press under packed.

The Press std curve shows how this shop runs the press on a regular basis. Notice the hump in the TVI curve from 25 to 50%. Not an uncommon condition on many presses.

The STX opt curve is much smoother than the Press std curve, missing the hump from 25 to 50%. Also, run at virtually the same densities the dot gain (50%) and overall TVI is lower at all points than the normal press set-up.

Even the two STX over pack conditions produced smoother overall TVI curves than the press standard set-up. While the TVI is higher in most cases this is to be expected when adding that much squeeze to a blanket that really does not need it.

I will continue to write about this press trial for a least 2-3 more weeks. There is a great deal of data and information to still go over. I even have some sheets here I will be doing additional readings on.

If you would like more information about the MacDermid Stabil-X blanket, please contact me and I will put you in touch with the right people at MacDermid.