How To Print Posters with Photoshop (Mac)


This document will instruct you on how to print an Adobe Photoshop document on the large format color printer available at GroundWorks. It covers how to take a poster file you've already created and set it up for printing on our printer, but not how to create a poster from scratch in Photoshop.


Step 1: Open your file


Find and open the Adobe Photoshop


In Adobe Photoshop, choose Open from the File menu. Select your file and click Open.

Step 2: Resize your image

Manipulating the physical size of your image directly affects its file size: the larger the physical dimensions of your image, the larger the file size will be, and the longer it will take to print your document. To save yourself time and aggravation it is best to print at a resolution no larger than 150 dpi. Any additional data from a higher resolution only serves to slow down your print job, and doesn't provide noticably better detail.

If your file is already set to the print size you wish (height and width), and to a resolution of 150 dpi, you may skip this step and move on to Step 3.

If this is not the case, then you will need to resize your image file.


Choose Image Size from the Image menu.

  • Check the box next to Constrain Proportions.
  • Uncheck the box next to Resample Image.

This will allow you to change the resolution of your image while simultaneously and proportionally changing the document's print size.


Change your resolution to 150 pixels/inch. (Don't click OK yet.)

Your Width and Height will increase proportionately. This will give you the maximum size image you can print while still maintaining a good quality.

Once you have set the resolution to 72 pixels per inch, you may discover that your document's dimensions (width or height) are too large for the printer's 36-inch wide paper. In this situation, you will need to adjust them:


In the Image Size window, check the box next to Resample Image.

You may now change the width and height without affecting the resolution. Use this option to decrease the size only, because increasing either dimension beyond your original size will decrease your image quality. As long as the Constrain Proportions option is checked, the dimensions will change proportionally.


When your image is set to the size you would like to print, click OK.

Note: If your image is not oriented so the dimension along the top of your poster is under 35 inches, then select Rotate Canvas from the Image menu, then select 90° CW from the submenu to rotate your image 90° clockwise.

Step 3: Save your file


Choose Save As... from the File menu


In the dialog box that appears, type a descriptive name for your file.


Select Photoshop EPS as your format.

Note: If the Photoshop EPS option is dimmed, click Cancel and make sure that your image has been flattened. You may need to select Flatten Image from the Layer menu.


Navigate to the Postershop Queue and click Save to save your file into the queue.


In the EPS Options window that appears, click OK.

Step 4: Preview your file

Once your file has been saved to the Postershop Queue, ask one of the consultants on duty at the GroundWorks consultant station to preview it with you.

Examine the preview carefully, paying particular attention to fonts and the integrity of any images. If you are satisfied that your poster looks the way it should, then give the consultant approval to print it.


When your poster has finished printing, remember to let it dry for at least 15 minutes before attempting to roll it up. For posters with larger areas of color, we recommend waiting upwards of an hour. Please ask a consultant if you are unsure about taking your poster home. Also remember that the ink is water soluble, and will smear if you touch it with your fingertips or get it wet.