File Prep for Large Format Printing

Resizing Images

Your images should be scaled to the desired print size before sending them for printing. To correctly resize images, students should open their file in Photoshop, then do the following:

1. Go to Image → Image Size 

A screenshot of the menu across the top of the screen in Photoshop. After clicking the "Image" option, choose "Image Size" in the dropdown that opens.

2. Entire the desired dimension for the print. Your image must be ¼ inch smaller than the width of the paper. If your paper is 24 inches wide, your smallest dimension cannot exceed 23.75 inches.

3. With the Resample box checked, enter an appropriate resolution. Many images have the default resolution of 72 pixels/inch, which is screen resolution. The minimum PPI (pixels per inch) for printing is generally 300 pixels/inch.  

A screenshot of the Image Size menu in photoshop. A preview of the photograph being edited is shown on the left, and the settings are on the right. The editable settings are set to a width of 23.75 inches, a height of 17.625 inches and a resolution of 300 inches. The box for "resample" is checked, and in the resample drop down, the option "Automatic" is chosen.

4. In the drop down list next to Resample, there are multiple selections for which algorithm photoshop can use to enlarge or reduce the image. You can experiment with several to decide which method works best with your image. There is no one best option — the level of detail present and the original size of your image will influence which choice  looks best.

A screenshot of the dropdown menu of "Resample" options. The options are Automatic, Preserve Details (enlargement), Preserve Details 2.0, Bicubic Smoother (enlargement), Bicubic Sharper (reduction), Bicubic (smooth gradients), Nearest Neighbor (hard edges), and Bilinear.
A screenshot of the Image Size Menu. The Resample box is set to Nearest Neighbor (hard edges). In the image preview, the image has crisp edges.
A screenshot of the Image Size Menu. The Resample box is set to Automatic. In the image preview, there is some distortion and blurring.

While automatic resampling often works well for photos, it can create a halo of distorted color when working with a highly graphic image like pixel art. Nearest neighbor preserves clean lines and shapes.

5. Make sure to check your image in the preview at 100%. You can drag the image in the preview box to check the most important sections, to ensure that all components of the image look good at the size and settings you’ve chosen.  

A screenshot of the Image Size menu. In the preview box on the left, the preview is zoomed into the face of a groundhog.

Checking to see that the face is not too pixellated or too blurred. 

A screenshot of the Image Size menu. In the preview box on the left, the preview is zoomed into a red rectangle.

Checking to see that digital components added to the image don’t have any added halo.

Color Proofing for Printing

Note that without a color-calibrated monitor, color proofing will never be exact. There are, however, steps that can be taken to better predict the color of your print. While the 9900 printers are capable of producing a large range of colors, no printer is able to exactly reproduce colors as they appear on a computer screen. Very bright colors will often appear darker or tinted to a different shade. To see which colors will be affected, open the image in photoshop and do the following: 

1. Download the Epson paper profiles by clicking this link. 

2. Unzip the file, then install it by copying the Pro9900_7900.profiles file into the folder Macintosh HD > Library > ColorSync > Profiles

3. In Photoshop, go to View → Proof Setup → Custom

A screenshot of the menu in photoshop. In the top menu bar, "View" is selected, and then "Proof Setup" is selected from the dropdown menu. "Custom" is then chosen from the drop down menu that opens to the right.

4. If the profiles were installed successfully, you should now see a list of Epson papers in the Device to Simulate drop down list. Choose the paper type you intend to use. Paper types that end in _MK are for printing with matte black ink, and paper types that end in _PK are for printing with photo black ink. The ink type should match the finish of the paper. 

A screenshot of the Customize Proof Condition Window. Next to "Device to Simulate" is a drop down menu where "Epson Stylus Pro 9900_7900 EnhancedMattePaper" is selected.

5. After hitting OK, Photoshop should now simulate what your image will look like when printed.

A photo of a groundhog with a rainbow rectangle around it. The colors are bright and the image is vibrant.
A photo of a groundhog with a rainbow rectangle around it. The colors are duller and the image is less bright.

Before and after changing the Proof Setup.

6. To easily see which areas have had their color changed, go to View → Gamut Warning. Photoshop will show which colors are out of the printer gamut, which is the technical term for the range of color the printer can produce. These out of gamut areas are highlighted in gray. These areas will still print in color, it is just a warning of which colors will not be accurately reproduced.

A groundhog with a gray rectangle around it.

Photographs are usually less affected by the printer’s color limitations, while high-saturation colors in digital work are often out of gamut. Desaturated colors fare better.

7. You may wish to readjust the colors or contrast in your image after seeing the print preview. Do this as you normally would.