PIEZOGRAPHY BW - PROBLEMS CENTERING IMAGES
Please report errors or omissions to Bill Bergh - bill@cone-editions.com

When we release the Piezography driver, we print many images and use finely divided rulers, and measure the margins to make sure that the centering algorithms are very accurate.

We get a number of calls with people having trouble centering the images.  There are a couple of issues that cause problems that are easily corrected. 

PiezographyBW takes full advantage of the Epson print head capabilities, and prints a tighter dot structure than the Epson CMYK driver.  A CMYK driver needs to dither dots in a pattern that will use the C, M, and Y inks to create the illusion of many colors.  When the color value approaches the lightest values near white, the CMYK driver spaces the dots farther and farther apart. Most CMYK drivers do not print any thing below about 5% because the dot pattern is spaced so far apart it becomes visually annoying.  Because the PiezographyBW driver is optimized for a monochromatic inkset, we begin printing at 1% ink black at the highest DPI the printed will allow, and continue so up to 100% black.  In other words, the dot spacing is programmable - and we print all black values at the tightest dot pattern the printed will allow.

When driving the printed in this mode, the firmware of the printer requires greater margin allowances than those listed in the Epson printer manual, and these need to be understood in some cases to properly center an image.  The Margin requirements are defined in the PiezographyBW Manual on the CD disk.  Any new updated versions of the manual can be found http://www.inkjetmall.com/store/ts/piezobw_update/

Note - VERSION 6.X.X AND ABOVE
Starting with Version 6.0.0 - Image offset features were added to the Piezography interface to help with precise image placement on a sheet of paper. On the Piezography BW window - you have the choice of centering the image -or- using the image offset features. People that print greeting cards etc. need the ability to move the image down and to the right so that the card media may be folded. The image offset feature allows for this without having to add white space to the left and top of the image in Photoshop.

If a person is having problems centering paper with Version 6.x.x - in some cases, it is the specific printer itself that is offset due to some printer misalignment. For a person that has a printer that whose margins are continually off by a measurable amount - it may be easier to use the Offset features to center the paper, to counter a printer flaw.

PROBLEMS & SOLUTIONS
1 - FILE SIZE EXCEEDS PRINTER MARGINS (Image Clipped)
2 - WHITE SPACE ADDED AROUND IMAGE
3 - UNEVEN TOP AND BOTTOM MARGIN REQUIREMENTS
      cause perception that the image is not centered
4 - DIFFERENCES BETWEEN THE EPSON DRIVER AND PiezographyBW driver using the
      MAXIMUM selection -  (Piezography BW Version 5.x.x and below only)
5 - USING WHITE SPACE TOP and LEFT TO CONTROL IMAGE PLACEMENT 
      (Piezography BW Version 5.x.x and below only)
6 - EPSON PAGE SIZE WEIRDNESS
      What paper size you select may not be the size that you thought you were selecting.

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1 - FILE SIZE EXCEEDS PRINTER MARGINS
If you are printing an image and suspect that the image is getting clipped, you may be exceeding the printable area of your particular printer.  For any printer, there are margin requirements that are mandated by the printers firmware.  The reason for these vary, and include problems guaranteeing that the dots are precisely placed on the right and left edges, and having enough paper left at the bottom to eject the paper, when printing is finished.

These printer margins are set in the printers firmware and are values the print driver does not control.

In practical terms what this means - is that you can not print an 8.5 x 11 image on 8.5 x 11 inch paper.  This seems pretty simple - but to someone new at printing, it is not necessarily obvious.  See topic number 2 below.

PROCEDURE
Make sure that you are sending images that are no larger than the printable area for your particular model printer.

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2 - WHITE SPACE ADDED AROUND IMAGE
Related to topic 1 above, many people mistakenly create a white image that is the paper size (example 8.5x11 inches) and then paste the smaller photographic image inside this white sheet.  Their idea is that they can then move the smaller photographic image around on its layer and control the placement on the printed sheet of paper.  The problem with this method is that the original size of the image was 8.5x11, and this violates the printable size the printer can handle.  Something will be clipped during printing.  Because it is part of the white space that is clipped, the smaller photographic image appears to be not centered on the printed sheet.

PROCEDURE
It is better to not add white space around the image.  Crop off the white space and trust the centering algorithm.

White space can be used on the top and left margins in conjunction with the "Maximum" setting to control precise image placement.  Refer to topics 4 & 5.

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3 - UNEVEN TOP AND BOTTOM MARGIN REQUIREMENTS CAUSE PERCEPTION THAT THE IMAGE IS NOT CENTERED
This topic is a bit trickier to understand.  As an example we will discuss the 1160 printer and a media size of 8.5x11 inches.  The Printer firmware requires a top margin of 0.375 inches and a bottom margin of 0.625 inches - for a total of 1.0 inch top/bottom margin.  This means that you can fit a 10 inch image on the sheet, BUT, it will not appear to be centered.

If the image was printed in the portrait mode, the bottom margin (0.625 in.) will be appear approximately twice as big as the top margin (0.375 in.).

If the image was printed in landscape mode - the left side comes out of the printer first.  When the image is fully printed and the artist pulls the print from the machine, then rotates the print 90 degrees to look at the print.  Now the border of the right hand side (bottom as it was printing) of the print appears to be twice as large as the left hand side (top as it was printing).

PROCEDURE
Option 1 - Trim the paper on the bottom so that the borders match.

Option 2 - If it is undesirable to trim the paper, an you want the print to be perfectly centered top to bottom, (or left to right for landscape) you will have to change the image size.  Because of the uneven margin requirements of the printers firmware, you can not print a 10 inch image centered on 11 inch paper.  Try changing the image to be 10 - (0.625 -0.375) = 9.75 inches.  Now there is enough room to have a .625 margin top and bottom.

Option 3 - This option is not recommended, but has been known to work.  You can lie to the printer and define a custom paper size in the Epson page setup box that is longer than 11 inches.  If you do this - just watch out for the last stripes that are printed on the page.  If the paper runs short as the last stripes are laid down, the printer may eject the paper before the dot patterns have finished printing.

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4 - DIFFERENCES BETWEEN THE EPSON DRIVER AND PiezographyBW DRIVER USING THE MAXIMUM SELECTION (Piezography ver 5.x.x and below only)
The Epson Page Setup box has a selection for "Maximum.  When you select this option for Epson printing, there is a message box that states that this option allows you to extend the printable area but that the quality may suffer.

The PiezographyBW Plug-in treats the "Maximum" selection differently.  Selecting Maximum in the Epson Page Setup box, overrides the centering option, and causes the Piezography driver to top left justify the print.  In other words, the print will be printed in the top left corner of the paper, minus the printer margins.  (The narrow white space at the top and left are put there by the printers firmware.)

PROCEDURE
The "Maximum" selection is found on the Epson Page setup dialog box. Refer to the Epson printer manual if you cannot find it. Selecting the "Maximum" selection will override the "Center" option when exporting through the Piezography BW Plug-in.

The "Maximum" selection can be useful in a couple of ways.  When printing test images that are small, you can print the test at the top left of the page.  Rotating the page around, it is possible to get 4 tests on one sheet of paper.  A good example is printing the 21 step test strip when trying to tune in a new unsupported type of paper.  Another example is for precise image placement, which is covered below in topic 5.

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5 - (Piezography ver 5.x.x and below only)
USING WHITE SPACE TOP and LEFT TO CONTROL IMAGE PLACEMENT
Many users are printing greeting cards, or other promotional materials.  The greeting card is a good example  because the image needs to be moved down and to the right so it will be inside when the paper (card) is folded. By selecting "Maximum" in the Epson Page setup dialog box, and it is possible to push the image down and to the right with precision.

PROCEDURE
You can add some white space to the top and left of your image easily in Photoshop by making sure that pure white is your background color and then clicking on "Image" -> "Canvas Size".  In the Canvas Size box, move the "Anchor" to the bottom right corner.  This will ensure that the additional canvas will be added to the top and the left of the image.  Photoshop will add canvas using the background color, in this case - white.  Change the image height and or width sizes to add the required offset.  When calculating the offset size - you must take into account the printers required left and/or top margins.

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6 - EPSON PAGE SIZE WEIRDNESS
There are a few quirks in Epson's paper sizes as well that may cause problems. These can best be explained with a real world example.

The Epson driver for the 1200 returns a page size of 4.46 x 6.46 in. to the Piezography plug-in, when "Photo Paper 4x6 in" is selected, which would cause a centering problem when using 4x6 in. media.

Later printer drivers, the 1280 for example, have a second paper selection "Photo Paper 4x6 in. No Perforations"; and the 1280 page setup returns a proper paper size of 4x6 in for this selection. So obviously the original intent for 4x6 photo paper for the 1200 was designed for Epson specific media that had perforations that were to be torn off.

For the 1200, in this case, if the user wants to control the exact paper size, the user should select the "User Defined" paper size and specify the values required for 4x6 in. media.

Using the custom paper size features of the Epson page setup, and the Image Offset features of the Piezography driver should give anyone full control of the page on these desktop printers.