Sliced Banner Prints not Lining Up

[bobbyizq]

I created a banner that is 11x42 inches and sliced it into three 11x14 prints. I used the slice tool to cut the 11x42 layer into three vertically and exported them as jpg images using the Export for Web (Legacy). When I open each image in Photoshop and merge the layers, they line up perfectly, But when I print each image, the prints don't line up. I have Borderless Printing enabled and disabled all print scaling options. I'm unsure what is happening here, but I can't use these prints as a banner. What do I do?

[Stephen Marsh]

It doesn't sound as if you have any overlapping areas for tiling, so perhaps you need to adjust your file setup, expectations and/or choice of printer.

By the way, the slice tool was originally designed for web banners, not print banners when using save for web which has limitations in pixel dimension input of 8192 px on the longest edge.

There are custom scripts that can output slices without the limitations of save for web.  That being said, I wouldn't use slices anyway as I'd be looking for overlapping content on each tile.

Another option is to save to Photoshop PDF format as a single banner and use Acrobat Reader to print tiles.

[bobbyizq]

My long dimension was 14 in at 300 ppi which is 4200 px and this is less than 8192 px so I don't see the problem here. The problem is not with the slicing because I can open the slice images as layers and line them up edge-to-edge and it's perfect. The problem is with printing in that it looks like at least one of the images was scaled even though I didn't enable scaling. I must be missing a print setting. I have an Espon P-800.

[Stephen Marsh]

I was just noting that the slice tool was never intended for making tiles for printing and that save for web has limitations for input.

The problem as I see it is that you have no overlap and are expecting borderless printing to deliver tiled prints that will join together perfectly to create a three section banner,  presumably printed on a device which isn't capable of printing the banner in a single piece.

As sound as the theory may be, there are obviously practical issues.

[Conrad_C]

I have Borderless Printing enabled and disabled all print scaling options.

By @bobbyizq

Which of the Epson 11 x 14 Borderless options was used for printing? (Your options for the P800 may differ from mine)

[bobbyizq]

I don't show any of the options ypur're showing. I only have a checkbox in Printer Preferences for the Epson P-800.  There is a Center o Page and Scaling option that are not tied to the Borderless option. I have these options disabled. Is it possible that the Epson driver is scaling when Borderless is checked.

I tried a different approach from Slicing and Export to Web Legacy to divided my banner into three equal parts I set Rulers to add Guide Lines at 14 in and 28 in marks, then duplicated the image, cropped each section and saved as PSD files. I printed each section file using the same print settings and got the same misaligned results. So in my mind, this confirms that the problem is specifically with what I'm doing to print each section and not to create each section. 

[Conrad_C]

OK. If your options are different then it's safe to assume, as you said, that the Epson printer driver is scaling to achieve borderless printing. I think this is the root cause of the problem. Because when I look at the images of the prints up against each other, bits are missing that should be achieving the seamless transition. I think those bits are cut off by the slight enlargement during printing. The bits are scaled past the edges.

A little background. Epson borderless printing is designed for photos, not graphic arts, and definitely not designed for tiled images. So I’m not surprised that this is happening. The reason for the slight enlargement is that if you are printing a single photograph, and you want it borderless, the Epson driver scales it up slightly to achieve the ink overspray beyond the paper edges. It’s the same thing you would do in a chemical darkroom: Put 11 x 14 paper under the enlarger, and set the enlarger to make the image size slightly larger than the paper to eliminate all borders. Most people don’t notice that a sliver of the photograph went past the paper edge. So that works as expected on Epson printers, replicating the traditional darkroom method.

That scaling to achieve borderless works great for photos, but not in any situation where you need to maintain specific dimensions such as graphics arts or technical drawings. So don’t use any borderless options for this type of non-photographic document.

Then what do you do about the slight mandatory edge margin for non-borderless printing? What Stephen said: Add an overlap, you probably won’t need more than 1/4 to 1/2 inch. The overlap is not printed at the actual paper edge, so nothing gets cut off, and the overlap ensures no gap. That will require four sheets instead of three. Needing to print one more sheet sounds unfortunate at first, but actually, three 11 x 14 sheets for 11 x 42 was never realistic in the first place because it doesn't allow for overlap. If you look at how very large images are tiled traditionally in the industry, for example for a roadside billboard, there’s always overlap between the printed tiles, it’s an industry best practice to guarantee seamlessness, to technically leave no possibility of a gap when the tiles are combined.

The nice thing about your design is that there is no content anywhere near the edges. If there were, this would be an 8-sheet tiling job to preserve graphics on all four edges, and probably extending the image size to create a “bleed” area that will be trimmed. (That’s how “borderless” is achieved in traditional printing from a press.) But you should be fine with the current document, printing it as just one row of four 11 x 14 sheets with a slight overlap, because the only seams you have to resolve are in the middle. And do not enable the Borderless option.