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Piezography BW Banding Issues
Please report errors or omissions to Bill Bergh - bill@cone-editions.com

There are several reasons why banding can occur while printing with inkjet printers: Banding is essentially a series of lighter or darker bands running across the print, that are not part of the image. White banding is most often caused by print nozzles not printing or misfiring. Dark banding across the entire image is often caused by paper feed issues. Banding in a particular tonal range that does not extend through other tonal ranges (or color ranges with color printing) can be related to a physical misadjustment of the print head.

BANDING CAUSES:
1 - WRONG DPI SETTINGS SELECTED FOR PRINTING.
2 - DIRTY OR CLOGGED NOZZLES
3 - MISALIGNED NOZZLES
4 - MIS-FIRING NOZZLES
5 - PAPER FEED PROBLEMS
6 - PHYSICALLY MISALIGNED PRINT HEADS
7 - BANDING CAUSED BY SCANNING
8 - BANDING CAUSED BY BAD PRINTER CABLES

SOLUTIONS:

1 - WRONG DPI SETTINGS SELECTED FOR PRINTING.
To get the best prints possible you need to select the finest mode the printer can print. Even for experienced printers, many times the cause of the problem was that the printer settings have reverted to 360 DPI draft mode. (When using the Epson Driver, 360, 720 DPI or high speed or Bi-directional printing can result in a poor print). This happens to the best of us and is a waste of good paper and ink. The best print mode is usually the slowest. While we all wish inkjet printing was faster, it is better to wait a bit for a great print in the highest quality (slowest) mode.

PROCEDURE:
It is a good practice to double check the printer settings prior to starting a print. The Epson page setup allows you to save a set of print settings, however many a good sheet has been ruined trusting this. It seems more reliable on the Mac platform, more problematic on the PC platform.

2 - DIRTY OR CLOGGED NOZZLES.
Typical symptoms are usually very fine light bands that are in a specific tonal range (or area of color when printing with color inks). When you are first switching inksets, or over time as you print, it is not uncommon that some nozzles will plug up. This is part of dealing with inkjet printers and trying to produce fine art from relatively inexpensive printers. Fortunately the printer manufacturers have given us tools to deal with this issue. Many clogs develop when you run out of ink unknowingly and air is introduced down into the print head. Clogging problems can develop as you change ink cartridges for the same reason.

PROCEDURE:
Consult your printer manual and learn about the cleaning utilities that are part of the printer software. In your printers Utilities menu, run a nozzle check test. The entire pattern should print. A missing line will result in banding. Perform cleaning procedure to unclog missing lines. Cheap typing paper is perfectly fine for this procedure as you are just trying to see that all the nozzles are firing correctly.

2A - MINOR CLOGGING.
The main trick here is to avoid excessive cleaning cycles. If the printer nozzle check pattern shows improvement after a cleaning cycle, but is not perfect, then run another cleaning cycle. For general nuisance minor clogs this is all that is required. However if you have run the cleaning cycle 3 or 4 times with no improvement - then stop, to avoid wasting ink. 100 cleaning cycles in a row will probably damage the machine.

2B - MAJOR CLOGGING SWITCHING TO A NEW INKSET OR WHEN CHANGING CARTRIDGES.
Typical symptoms can range from very fine light bands that are in a specific tonal range as discussed above, or bands of flat tones that look like the image is solorized or posterized, where darker dots are not being printed over the underlying tones - so there appears to be a loss of detail. If you have just switched from the Epson OEM inkset and are installing a new archival inkset, or are having problems after replacing a set of cartridges, often the cause was air being introduced into the print head. Statically charged micro-bubbles can stubbornly cling to the small printing orifices and can be very hard eliminate. The best method of clearing this kind of clog is patience and time. Turn the printer off after your attempts to clean the heads and let it set for a few hours or preferably over night. Ninety percent of the problems will disappear by the following morning. While the printer is off, the print head is parked in its home position and the print head cap is raised to seal the print head to keep it from drying out. Over time the micro-bubbles disperse, and the problem is solved.

2C - MAJOR CLOG from HELL.
Look for the Windex Treatment on the FAQ’s.
http://www.inkjetmall.com/store/ts/piezobw.htm

3 - MISALIGNED NOZZLES
Banding can occur due to the misalignment of the print heads. Flawless prints are made with precise alignment of rows of minute dots. Also it is imperative to align the printers nozzles on the thickness of paper that you are printing on. This is one time that cheap typing paper will not work. Save any ruined prints, or bent pieces of good fine art paper, as these sheets are worth their weight in gold for alignment sheets. You do not have to print on the coated side of the paper - the back side will do. The paper can be rotated around at least 4 times and if you get creative you can get many alignment patterns printed on the same piece of paper.

PROCEDURE:
Consult your printer manual and learn about the alignment utilities that are part of the printer software. In your printers Utilities menu, run a nozzle alignment test. The entire pattern should print. The print head alignment procedure varies the placement of the vertical dot patterns so that the vertical lines are offset to the left and right and the center pattern in theory should be the best aligned. You should look at the alignment patterns with a loupe or magnifying glass and determine which pattern is best aligned. You tell the printer which pattern is the best if it is not the center - and the printer adjusts the heads accordingly. People often ask how many times should they run the test? The answer is until it is right and the center group is best.

HOW OFTEN SHOULD ONE DO THE ALIGNMENT PROCEDURE?
FIRST - When ever you change thicknesses of paper. An alignment that is perfect for thin glossy stock will not be correct for a thicker water color paper.

SECOND - We always start the day with an alignment check. Why start out the day with a ruined print? It takes a few minutes to verify that the first print of the day is a keeper. This is part of being a professional printer. Tune your hardware and then get to work.

THIRD - Whenever you notice that your prints are starting to band during the course of the day. Printer quality here differs among the different models. The Epson 3000 can wander off sometime after lunch if you are printing all day. The 1160 can go all day (or maybe all week) without realigning. Get to know the quirks of your individual printer and do an alignment when you suspect it is about to ruin a print.

4 - MIS-FIRING NOZZLES
The nozzle check and alignment check are actually good tools to assess the health of the printer. Look very closely at the alignment check with a loupe or magnifying glass.

4a - NOZZLE CHECK USED AS A DIAGNOSTIC AID.
Are all the lines in a step pattern? A line may jump up or down resulting in a gap. If the steps of the nozzle check are not perfect, and cannot be fixed by cleaning, the print head may be bad. Nozzles that are sprayed in the wrong place can result in find razor thin bands.

4b - ALIGNMENT CHECK USED AS A DIAGNOSTIC AID.
Are all the vertical dot line patterns well formed? Are the dots weaving back and forth from the vertical line? Is there a secondary set of dots that look like an over spray? These symptoms can result in razor thin bands on the printed image.

PROCEDURE:
If there are serious problems as listed above, these may imply that the print head is defective or dying. Some of these may be caused by inkjet streams being deflected by a seriously dirty print head. If you have printed many hundreds of prints, then it may be time for a serious head cleaning. If cleaning does not help the problem, it may be time for a trip to the Epson repair depot.

5 - PAPER FEED PROBLEMS
Banding can be caused by physical paper feed issues. Typical symptoms will be dark banding across the entire image from edge to edge of the image. Printing on paper too thick for the printers paper feed mechanism can result in slippage of the pinch rollers. Improper adjustments of the printer hardware can cause paper skewing or improper advancement. If the paper does not advance exactly the right amount, the tiny rows of dots may overlap and the result appears to be dark bands.

5a - PAPER THICKNESS ISSUES
We are all pushing these desktop printers past their intended design when we try to run thick water color paper through the machines. The Epson 3000 stalls out on 350g/m2 paper and squeals, and dumps a lot of ink in the center of the sheet. 310g/m2 paper will work in some machines and not others. The more common weights of 225 or 190g/m2 and anything thinner work well.

For printers like the Epson 3000 that has 3 different paper paths, try out all three. We typically print the thicker papers using the tractor feed slot - this is perfect area for feeding paper in a straight-through path. Do not engage the tractor feed mechanism, but rather place the paper above the feeds. Inserting the sheet will cause an auto feed to occur. After the edge of the paper touches the sensor, you will have approximately one second to make certain that it is aligned properly. The paper will feed in about 1/2 inch. Some people find that their best prints are made using the top manual feed slot. Perversely there are some people that can get a perfect print only using the auto sheet feeder in the front. This may be a horrible way to feed in 17x22 inch thick water color paper, but if it is the only solution, use it. The 3000 is the last of a kind of printer. It has the old style large rubber platen (roller) like an old typewriter. The printer looks a lot like the old dot matrix printers with an inkjet printing mechanism installed. (Why put a tractor feed on a fine art printer?) The platen gap adjustment made at the factory is crucial to proper paper trajectory. Mis-gapped platens can cause the paper to skew to the side during printing resulting in a print that is not square. Paper slippage can cause a short print, resulting in dark banding. The stepper motor that advances the paper is one of the most often replaced parts on the Epson 3000 at the repair depots.

The smaller desktop printers only have an autosheet feed angled paper path. Typically there is a lot less problems with these printers. Success can be had up to about 330 g/m2 paper, but the printer really struggles to pull this through and it is not recommended. These printers have a stainless steel shaft that is very thinly coated with textured rubber material. They tend to pull the sheet through very evenly.

PROCEDURE:
If your printer will not accept the thicker papers, there is not a lot you can do about this. Print on thinner papers.

If you are on an Epson 3000, try all three paper pathways to see if one of them is the best. If your printer is skewing the paper to one side as it prints, this is something that Epson will have to fix. Print out a 20 inch line on the back of sheet of paper and measure it with a ruler. If your print is 19.5 inches in length, you have a printer problem. Slippage can be caused by very smooth coatings on some papers. Try a different paper if this is the case. We tried removing the covers and strengthening the internal springs for the pinch rollers, but with limited success. Any improvements we made were probably masking a deeper problem that is more correctly fixed by having Epson adjust the machine to manufacturing tolerances. If all else fails, the printer may have to be returned to Epson for servicing.

6 - PHYSICALLY MISALIGNED PRINT HEADS
Banding in a particular tonal range that does not extend through other tonal ranges (or color ranges with color printing) can be related to a physical misadjustment of the print head. This assumes that the nozzle check is good.

The desktop printers seem to be less problematic. We have not seen this to be much of a problem with the 1160 or 1200 etc. printer families.

The Epson utilities for aligning the print head have limited effect that assumes that the physical alignment done at the factory or repair center is perfect. The Epson 3000 user alignment utility only aligns the black to the magenta head. The magenta head is in the center of the three color heads. The three color heads sit on a plate that rotates. Only the repair depots and factory have the alignment utility to physically align the 4 heads together using the mechanical adjustments. If the plate that the three color heads sit on is not perfect that the cyan and yellow heads may not be tracking well. The alignment utility that we can use to align the print heads cannot overcome a gross physical misadjustment.

PROCEDURE:
This one is hard to diagnose and can only be fixed by Epson.

7 - BANDING CAUSED BY SCANNING.
We have provided a reference image on the Piezography BW CD as a reference for comparison. Print this image, or if this image is unavailable - the sample images from the Photoshop folders will suffice in a pinch. (They are only 72 DPI). If these images print free of bands, then you may have scanning induced flaws in your image. WE can't advise you on how to use your scanner, but large amounts of sharpening or other filters applied in the scanning software have been known to cause banding. Refer to "The Ideal Workflow" for some ideas on how to best prepare images for printing.

8 - BANDING CAUSED BY BAD PRINTER CABLES
There have been a few instances where customers called back to say that they traced the root of their banding problems to a bad printer cable. This is probably not a common cause, but has been known to exist. If you can borrow a cable or have an alternate cable you can use - this is worth a quick test.

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