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Author Topic: An approach to setting head gap and vacuum settings on larger printers.  (Read 356 times)

Doug Gray

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There has been some discussion on how to set inking levels for best results. Particularly in shadows but little in these other areas

One of the side effects from the various experiments I've run to get optimal prints is a statistical technique that proved quite effective.

Basically, it starts with the set of 64 RGB colors, evenly spaced on a 4x4x4 grid. This set is repeated 15 times leaving off three of the white patches to produce a standard, 957 randomized patch printer target. Duplicates are made as needed across roll paper.

Each printed target is then scanned. Each set of 15 printed colors is then collated and standard deviation computed and the overall average is printed out.

I have found tweaking the head gap as well as the vacuum setting in the 9800 improved the average standard deviation by about 40% over just using the defaults or what seemed to match an OEM paper. Most significantly, it improved the positional variation that I had seen earlier.  This has resulted in better profiles too.

I use some Matlab programs to process the data so it's a fairly simple operation. It should also be easy to do in Excel with a VBA function.

Just some ideas for the OCD amongst us.
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