Large scale poster printing can be expensive in colour or black and white. Here are my champagne results with beer budget priced methods, for large scale printing for wheatpaste. Officeworks staff have a high tolerance for experimental methods and are also the cheapest. It’s possible to print photographic images on a plan printer but the quality is less defined, black and white only, and more expensive than this method.
- Original image as high a resolution as possible (300/600 dpi)
- Resize/Resample to finished measurements at 150/100 dpi, LOW quality JPEG (can go lower than 100 dpi for billboard or larger scale)
- Crop into smaller pieces, save as PDFs
- Print set up: Poster, 100% Tile Scale, zero Overlap, check Crop Marks, A3 size, colour or B & W, laser print
- Test print a small section
Resolution Make sure the original image is as high a resolution as possible. The image has to go through several processes to get to the print stage and resizing to large scale loses a lot of the resolution. I’ve found digitally photographing everything including artwork at the highest setting on the camera is the easiest way to go, but if the artwork can fit in a scanner then use the highest dpi. Upscaling Once the artwork/image is ready for upscaling, resize to the finished size as a LOW quality JPEG file using “resize/resample” in whatever program you are using. Reduce the dpi to 150 or 100 (or lower for billboard or larger images) and save. Billboard printing resolution can go as low as 15 dpi, as the image is so far away it can afford to be grainy or pixellated. As a rough guide for colour printing, keep the file size under 6Mb per 2 x 1.5 metres. Black and white can be a larger file size as it seems to use less printer memory. Prepare for Printing Convert the JPEG to a PDF for printing. Black and white printing can work as one piece at 2 x 2 metres, but not colour. For colour printing, the image needs to be chopped up and printed in sections. If someone knows an easy way of doing this please let me know. I just pick a centre point in the image and crop it into equal sections making sure they all overlap a bit in case I’ve missed a slice when it’s printed. So a 2 x 1.5 metre image will most likely need cropping into four sections to print in colour. I don’t know why this is, but the Adobe Acrobat program jammed up two Officeworks printers on endless repeat of the same section when the image size was 2 x 1.5 metres. It wasn’t the file size that jammed the printer but the actual size of the tiled Pdf. The file size that worked was under 3Mb and no more than 1.3 x 1 metres in actual size. Printing Images for wheatpaste don’t work on an inkjet printer as the ink runs when wet. A laser print is colour-fast unless the image is really soaked and overworked. Once dry, the wheatpaste protects the image from the elements (a year and counting). Open the image in Adobe Acrobat and click print. Select “Poster” print, “100%” Tile Scale, “0” overlap, check CROP MARKS, A3 size, colour or B & W. There must be crop marks or the tiled images will be missing a few millimetres all the way round so won’t perfectly match the image next to it. I’ve given up trying to suggest portrait or landscape layout as the computer often over-rides the choice, but if you can pick, then go for the lowest number of A3 pieces per section as it works out cheaper. Test Print Always test a section before printing the entire piece. If there are any mistakes in the set up now is the time to fix them, not at the end of the run! Cut and paste The A3 tiled images can be trimmed with a border left on two sides to paste with carpenters glue/PVA against the next image. I usually paste about 6 together into a larger section so they are easily manageable for wheatpasting. Too large and it will be difficult to manage; too small and it takes ages to line up on the wall and allows more time for the police to arrive 🙂 Disclaimer: This is my experience for large format printing only. I’m not an expert in this area and there may be faster, easier and cheaper ways to do it.