How to Set an Exact Print Size in Lightroom

How to Set an Exact Print Size in Lightroom

Frustrating isn’t it. You have a great photo that you want to print in Lightroom, but you can’t seem to print it at the right size. Either the height is too large for the width or vice versa. Or perhaps the image fits the page, but with an important area cropped off. If you find yourself nodding as you read, then this article will explain what’s happening and show you how to produce exact size prints in Lightroom.

But before we dive into the Lightroom Print module, there are a few important things to understand about printing and print sizes. We’ll start with the Aspect Ratio.

Choose the Correct Aspect Ratio

The aspect ratio of the image is extremely important if you want to produce an exact size print. It measures the ratio between the long and short edges of the image. For example, if all the sides of the image are the same length, then the image is square and has an aspect ratio of 1:1. But if the longest edge of the image is twice the length of the shortest edge, then the aspect ratio is 2:1.

The problem the aspect ratio creates when printing an image where you want to set the size of the long and short edges. A good example of this is when printing a photo for a frame. A lot of frames, particularly in the UK use old photographic sizes like 8” x 10” which is an aspect ratio of 5:4. Now compare this with the default aspect ratio of most digital cameras which is 3:2. Because the aspect ratio is different, the image won’t fit the frame exactly.

Often when people encounter this problem, they try resizing the image. But when they resize the long edge of the image to be 10” they find there is empty space along the edges. Then when they resize the short side of the image to 8” they find part of the image is cropped off because the long edge is now too long. Some people even then try to change the aspect ratio of the image so that it matches the frame, but this distorts the image, which isn’t acceptable.

There are only two possible solutions to this problem:

1. Crop the image to match the aspect ratio of the frame and lose part of the image.
2. Use a different frame or mount that matches the aspect ratio of the printed image.

Now let’s discuss the next problem which is the image resolution.

Image Resolution

When printing, you need the image to have enough resolution to produce a photo quality print. Generally, this will be 300dpi, but it does depend on the paper you are using as well as the image subject matter. A matte paper for example needs less resolution to look good than glossy paper.

The easy answer to this is to enlarge the image if it’s not big enough, but there are limits that you might run into. If you enlarge an image too far, the fine details that you expect to see in a good print break down and the print quality looks poor. Ideally, you should start with an image that will produce your desired print size at a resolution of 240dpi or higher. The Lightroom Print module will then handle the image resizing automatically when you print but without risking the print quality.

Image resolution is quite a lengthy subject so if you want to know more see my Image Size and Resolution tutorial for printing.

Print Module Settings

Having covered these important points, let’s turn our attention to the Lightroom Print module and how we can use the controls to produce an exact print size. You can see a screenshot of the Print module interface here.

On the left of the interface (number 1) is a series of print templates you can use. Clicking one of these configures the page layout with those settings. These settings are the ones that you will find over on the right side of the interface (number 2).

Print Templates

The print templates can be extremely useful but there is no saying they will match the size of the print you want to make. They may also be different to your paper size and therefore require trimming to remove the excess paper.

Here the template “(1) 4 x 6, (6) 2 x 3” was selected. This produces the selected image seven times at the dimensions indicated in the template name. This template would typically be used by a commercial photographer who is selling prints. I’m sure this will remind you of school photos.

But what’s important about this template (and a few of the others) is that they use the “Picture Package” style in the “Layout Style” panel. You will find this at the top of the panels on the right side of the Print module.

Both the Picture Package and Custom Package options provide access to something called a Cell. Cells are important because they make it easy to set an exact size for the image you want to print.

Print Cells

Over on the right of the interface we have the “Cells” option expanded. We can use these controls to add new pages to the print package as well as adding new cells. A cell is just a way of placing an image onto the page with the required size as in this screenshot.

When you want to produce several copies of an image at exact print sizes, creating a layout with cells may be the solution. Despite this, be aware that adding a cell with a different aspect ratio to your image will crop the image. You can see an example of this in the screenshot where a “3 x 7” cell was added causing the image to be cropped on the top and bottom.

What you may not also realise is that the other cells on this second layout page have the wrong aspect ratio for the image. Because of this, these images are also being cropped but as the difference isn’t that great, you don’t notice it.

Adding Cells to a Layout

If we look at the “Cells” panel more closely you will see the different sizes of cell you can add.

In the top part of the panel, you can see six buttons displaying sizes like “3 x 7” and “8 x 10”. These are the sizes of the image to be displayed in the cell and are in inches. If you don’t like using inches and would rather use something like mm, you can switch in the “Rulers, Grids and Guides” panel.

When you click a button, it adds an image cell to the page of the selected size. If you don’t like the 6 sizes, you can click the dropdown arrow to the right of the button to select another. There’s also an “Edit…” option where you can define your own custom size.

A further option to print an image with an exact size is to resize an existing cell. Click the cell on the page that you want to resize and then use the “Adjust Selected Cell” sliders at the bottom of the Cells panel.

Important Image Settings

Earlier I said that when you select a cell that doesn’t match the aspect ratio of your image, the image is cropped to fit the cell. To be completely accurate, that doesn’t always happen, and you can Lightroom’s behaviour in the “Image Settings” dialog.

The setting that causes the image cropping is the “Zoom to Fill” option. When ticked the image is magnified to fill the available cell space on all sides. This is important because it ensures your image has the exact dimensions set for the cell. If you untick the option, you will find the image is resized so that it fits in the cell entirely without any cropping. If the aspect ratio of the image doesn’t match that of the cell it creates additional white space around the image, which changes its size.

Another option that can change the size of the image is the “Photo Border”. When you want to print an image with an exact size ensure this is turned off. It adds a white border inside the cell which will change the image dimensions. It’s only useful when printing several images on the same sheet as it helps to separate them.

Summary of How to Set an Exact Print Size in Lightroom

In this article we’ve looked at how to produce a print in Lightroom using an exact size. The easy way to do this is to use the Cell panel in the Picture Package or Custom Package Layout style. This allows you to place the image on the page and for it to have the exact dimensions you require. Whilst we’ve looked at an example where the image is repeated multiple times on the page, you can easily create a layout with a single image of an exact size.

This article has also assumed that you want to print an image of an exact size. It’s also possible to use the Lightroom “Print to JPEG” option to produce a JPEG image with an exact size. This can be especially useful when you want to send your photos for printing by an online lab. To find out more read my article “Using the Lightroom Print to JPEG Feature”.