Wide Load: Tips for Printing LARGE

Background

Wide format printers are getting cheaper and more economical, making large prints like 13x20, 20x30, and larger possible even for the advanced amateur. Logic dictates that a wide format inkjet printer is nothing more than a big printer and that printing to a wide format printer should be no different than printing to your typical desktop inkjet except that it allows you to work with larger page sizes. Unfortunately there are a lot of snags that you may encounter when printing (very) large prints. Most involve printer/driver setup and are easily corrected while others may require a rethink on how you have your equipment connected, what type of equipment you are using to print, whether or not your current hard drive has the capacity for wide format printing, whether or not you need more RAM, etc. Let's take a look at printing large and we'll try to cover all the common missteps in the minefield. We'll keep both Qimage and PhotoShop in mind for this article as those are popular PC/Windows printing applications and are the applications that I deal with most in wide format printing.

Page Size

Wide format printers often handle paper/page size differently than your average inkjet, particularly with respect to borderless or "no margins" printing. First, it is important to realize that there are two methods that drivers use to perform borderless printing: expand page and expand prints. In the expand page mode, the driver simply increases the size of the page so that it is larger than the physical paper size. In this borderless printing mode, the driver will actually show a printable area larger than the physical paper size. For example, a 16 inch wide roll may show as 16.23 inches across in your printing software. What is actually happening is that the driver is printing approximately .12 inches off the left and right edges of the roll. With this method, it is important to print your large prints in the center of the page. For example, use "centered" or "optimal/spaced" in Qimage. This will ensure that the "overspray" that extends off the edges of the paper is minimized and you won't lose the edges of the print because they are printing up against one edge or the other. If you use something like "compact" or "optimal", Qimage will place the print at the left edge of the paper and .12 inches of the print will be off the page, cropping the print slightly. Epson calls this expand page mode "Retain Size" in their latest wide format drivers. In the older (7600/9600) drivers, this was the only option available so no options were visible. What you need to keep in mind with the expand page mode is that the driver expands the page size so that it extends slightly beyond the edges of the paper. In doing so, it is possible to print off the edge of the paper and lose some of your prints. Try to avoid this "clipping" by not printing anything all the way against the left/right edges of the paper when aligning your prints on the page preview on screen.

The other method of borderless printing (one that is used on most standard inkjet printers) is the expand prints mode. In this mode, the printable area remains the size of the paper (16.0 inches across for example), but prints are expanded in size. With this mode, you can specify 16 inches as the width and the driver will "artificially" expand the print to 16.23 inches so that the print is large enough for some overspray to the left/right: the overspray eliminates tiny slivers of unprinted paper at the edges due to slight misalignment of the paper. This mode is more common but often more confusing because every print you send will be slightly larger than what you specified. Even if you print 4x6 prints on a 16x20 page, the 4x6 prints will be just slightly larger than 4x6 and this may confuse people or prompt them to blame the printing software for the size problem when in fact it is the driver that took the 4x6 print and expanded it after the fact. If the expand prints mode (called "Auto Expand" by Epson in their latest wide format drivers) is being used, Qimage does have an option that can defeat the size expansion so that you can obtain prints of the specified size without the driver expanding them. See "Page Formatting", "Borderless Overspray/Expansion" in Qimage. Some drivers even allow you to turn this expansion off (or at least reduce it) by dragging the "amount of extension" slider all the way to the left in the driver. Keep in mind that doing this produces less overspray so any "sloppiness" in the paper loading mechanism may show up as unprinted slivers on the edges of the print.

Understanding software differences WRT sizing

All software including PhotoShop and Qimage must work within the
limitations of the printer which are defined by the driver. If you specify an impossible task, like printing a 16x20 print on 16x20 paper without using borderless printing, different software may handle the request differently. For example, if you don't specify borderless printing, the maximum size print allowable on 16x20 paper using the Epson 4800 is 15.766 x 19.333 inches. If you try to print a 16x20 using PhotoShop, you will be told that the print size is larger than allowed but you will be given a "Proceed" option. If you proceed, PhotoShop will print at 16x20 but will clip the edges of the print and you'll end up with a 15.766 x 19.333 inch print that has the edges missing. In Qimage, you will be told that the print size is larger than one page and will be asked if you want a poster. If you say no, you'll end up with a 15.766 x 19.333 inch print (same size as PhotoShop) but without the edges cropped off. These are just two different ways of handling the same problem and in both cases you end up with (no more than) a 15.766 x 19.333 inch print: a printer/driver limitation. It is important to recognize how different programs handle sizing tasks and in particular, what happens when you try to print sizes that do not fit on the paper. Whatever printing software you use, be familiar with how it handles sizing discrepancies.

Spooling options

Qimage will almost always send more (potentially much more) data to the driver than PhotoShop or other printing programs due to Qimage's interpolation process. As such, you must make sure that the printer is set up properly for large format printing. Not having the printer/spooler set up properly may result in partial prints, no print at all, or crashes due to the system not being able to handle the [large] amount of data being handed to the driver. First and foremost, go to control panel, select "printers and faxes", and right click on your printer. Select "Properties" from the right click menu and then click the "Advanced" tab. If "Enable Advanced Printing Features" is checked at the bottom, UNcheck this option. This is the cause for 98% of printing troubles when printing large prints as this feature can only handle a small amount of data and isn't meant for photographic printing so the option should remain UNchecked. The other options on that tab usually make little difference but I recommend checking "Spool print documents so program finishes printing faster" and also "Start printing immediately". Those options will ensure the best use of resources on the machine. Finally, click the "Print Processor" button and make sure that the right side is set to "RAW". If any other data type is selected, it is likely your photographic printing will not work properly. Click "OK" to save the changes.

Maximum print sizes

Some online sources report that the maximum print length in PhotoShop CS2 is about 90 inches. I have not confirmed this, but I can tell you that when set up properly, Qimage has no length limit. PhotoShop and most other applications that print photos try to send the image all-at-once to the driver: they basically hand off the entire original image at once and simply specify a print size for that image. Depending on the initial image size and specified print size, this all-at-once printing method can overwhelm the driver/spooler and lockups/crashes may ensue. Qimage has a "smart" handoff to the driver that passes the data in smaller chunks that don't overwhelm the system and can allow for much larger prints. With Qimage, you are only bound by the amount of RAM, virtual memory, and hard drive space available and by how well your print driver handles the printing task when dealing with the large amount of data normally used for big prints. Most of the big print failures that I've seen fall into three categories:

(1) Printer is connected through a network. I have not yet seen a reliable setup when printing through a network and working with large prints. My advice here is just don't do it! In fact, if your wide format printer is connected via an Ethernet cable, switch to USB and print directly to the printer via a local machine connected directly to the printer. There are dozens of complications that arise when trying to send large amounts of print data across a network so if at all possible, print from a machine that is directly connected to the wide format printer as a local printer. You will avoid a lot of hassles this way! It may be possible, depending on many factors, to have a reliable network printing setup to a wide format printer, but the complications are so diverse and varied that I don't dare get into that here. When dealing with "wide loads", it is best to avoid network connections altogether!

(2) Don't upsample originals. I've seen people scan 8x10 photographs at 2400 PPI ending up with a 1.4 GB file thinking they want the most resolution possible for printing large. In this case, the original photo only holds maybe 300 PPI of real information so scanning the photo at 600 PPI and then letting Qimage handle the interpolation makes more sense (and often produces better results). Your system and the driver will have enough to do processing your 10 foot long print, so don't hand it a 1-2 GB file unless you truly have enough resolution in the original to support it. If you have enough pixels in the original to support the resolution of the final image (like a montage or panorama using a dozen photos from a dSLR), your original images have reason to be big, but don't "oversample" lower resolution photos or "overscan" media at ridiculous PPI as this may do nothing but hurt you in the long run! Taking a 30MB original, for example, and resampling it to 400MB might make sense if you plan to print from PhotoShop, but if you are printing with Qimage, do not upsample that 30MB image because Qimage will do all the upsampling at print time very efficiently and with much less resources (RAM and hard drive space) if you simply print the original 30MB image!

(3) When using a photo editor or other software to prepare a final image for print, use a less proprietary and more internationally accepted standard like the TIFF format or even the JPEG format for the final image to be printed. Other formats such as Adobe's PSD format often have more overhead and put more stress on your system, not to mention that the public spec for such formats is often far behind what is used in the latest version of the software that creates those files. You may often be dealing with very large images when printing large prints. To decrease the overall resource requirements for the job and make the whole process go smoother, use a standard format like an 8 bit/channel TIFF file with no alpha channels and no layers! All print drivers are 8 bits/channel so there is rarely any need to carry 16 bit/channel through to the final print-ready image as it is just going to end up getting converted back to 8 bits/channel anyway for the print driver. Using PSD or layered TIFF's can put more strain on memory resources and may cause longer print times or even an occasional crash as the system tries to read a 400 MB image and print the 3.7 GB of data needed for a 720 PPI 40x60 inch print. For printing large, I recommend 2 GB of RAM with both the minimum and maximum virtual memory set to 4 GB. This should avoid most disk swapping unless your originals are extremely large.

(4) You can never have too much free hard drive space when printing large prints! Printing a 44 inch wide print that is several feet long can take 5 GB (yes, gigabytes) of hard drive space or more. As a general/safe rule of thumb, try to keep 10 GB free on the drive where your print driver spools data. If you print with Qimage, Qimage will not need much hard drive space to process the job but it is passing a lot of data to the driver and the driver will in turn cache that data to disk while it is spooling. Due to Qimage's high quality interpolation, it will almost always send more data to the driver than your average printing program, so don't assume that you have enough drive space just because you were able to print a print through some other software. Qimage rarely has a problem processing the job and will finish its printing task, but after the printing task is over (sometimes before), I've seen the print driver itself crash even when several gigabytes of free space remain on the drive so don't be fooled into thinking it isn't a drive space problem just because you have a few gigabytes free on the drive!

(5) I have assisted professionals with the above tips and have printed prints as large as 44 inches wide by as much as 10 feet long (44 x 120 inches) with no problem using Qimage. When printing super large prints like this with Qimage, however, I would recommend setting Qimage to interpolate no higher than 360 PPI for the final print. That means that if the page resolution (current driver base resolution) shown above the preview page on Qimage's main window shows 720 x 720 PPI or 600 x 600 PPI, set your interpolation levels to "High". If the resolution shown above the preview page is 360 x 360 or 300 x 300, set your interpolation level to "Max". When printing huge banners, you rarely need the maximum 600 x 600 or 720 x 720 offered by the driver, so setting Qimage's interpolation level to "High" instead of "Max" will cause it to interpolate to 1/2 the listed PPI.

When printing prints larger than about 20x30 inches:
Qimage's preview page shows Set interpolation levels to
MORE than 720 x 720 Med
600 x 600 up to 720 x 720 High
Below 600 x 600 Max

Use the above table as a good rule of thumb for printing prints larger than 20x30 inches to avoid system overload. Under 20x30 inches: just keep the interpolation levels set to "Max". While there should be no problem printing at "Max" interpolation level in Qimage well beyond this arbitrary 20x30 size on a capable machine, it will take longer to process and will increase the strain on the entire system (particularly with respect to hard drive space).

Summary

Hopefully the above tips will help clear up some of the confusion and questions being tossed around from people printing in wide format, particularly when using the latest Epson wide format printers which have some new options. I print wide format myself and have helped others like local camera store employees who printed 44 inch wide prints 10+ feet long from Qimage to display on the front of their store using the above tips. Most of the issues with printing large involve just setting up the equipment, system, and driver properly. I occasionally run into something out of the ordinary, but most of the time the information on this page is all you need to resolve any wide format printing problems even when they occur in software other than my own Qimage.

-- Mike Chaney