On Sep 6, 2005, at 7:45 PM, Matt Smolka wrote: Fellow list-members,
One of the projects at Ryerson University's Graphic Communication Program is to design a special project in which students design and carryout their own testing of a printing process.
In light of this, I'm looking at fingerprinting our GTO52 2/c as well as our DI 4/c presses using M-Real coated and uncoated stocks. What would be the ideal method in going about this? IT8 target? GATF testform? Can anyone provide me with links to resources or testing procedures?
Ideally, he aim is for a neutral grey balance as well as target wet densities. Printing conditions are such that SWOP standards are used even though it is a sheetfed press. I'm thinking that maybe we should be using GRACOL standards for this test and implementing the use of these standards for the future, unless someone can suggest reasons to keep using SWOP.
Data gathered here would be used to generate dot gain compensation curves for both uncoated and coated stocks for our premedia labs, i.e. Photoshop curves. The intent here is to produce a press sheet that can be profiled and used as a curve template for our Apogee RIP/Meta Dimension RIP as well as being used to "soft-proof" documents on lab workstations (which are profiled every week).
As far as using data for your Meta, Heidelberg has a control strip that can be printed and then read with a DTP 41 (or you can use a CCDot Press or any other densitometer that will read press gain). You would use Meta's Calibration Manager to collect the data. What you must remember is that this information from the press is generated from plates that are not going to be used for the other profiling data. You need to run out plates with no dot gain added to the plates. You would print sheets using these uncalibrated plates to determine how much gain you should add to each color plate, so they will be comparable to SWOP standards.
You then enter the data from the DTP 41 into the Calibration Manager, which adds the curve to the plates, and then run your profiling test.
Without adding the gain first, your press sheets may print a 50% as a 55%, not what one visually expects from a press. According to SWOP standards, it is something more like a 70% dot in the 50% swatch.
It is important that the density values used on the first test run, such as the recommended Gracol values, are the same on the subsequent runs, and forever after.
Matthew Kelly Technical Supervisor Litho Press, Inc. 4334 Milling Road San Antonio, TX 78219 210-541-0707
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