How do I Copy a Grid Line in Photoshop?

Unfortunately, you cannot directly copy a single grid line in Photoshop in the same way you would copy a guide. Grid lines are a visual aid that are generated based on the Grid Preferences. However, you can copy guides, which are very similar and serve the same purpose. Here's how to work with guides to achieve similar results:

Working with Guides Instead of Grid Lines

Since you can't copy grid lines, use guides instead, which provide a similar functionality and can be copied.

Option 1: Creating and Copying Guides Manually

1. Create a Guide: Drag from either the horizontal or vertical ruler (View > Rulers). If rulers are not visible, press Ctrl+R (Windows) or Cmd+R (Mac).
2. Select and Copy the Guide: Ensure the Move Tool (V) is selected. If your guides are locked, go to View > Lock Guides and uncheck the option. Click on the guide to select it. Copy the guide by pressing Ctrl+C (Windows) or Cmd+C (Mac).
3. Paste the Guide: Open the target Photoshop document. Paste the guide by pressing Ctrl+V (Windows) or Cmd+V (Mac). The guide will be placed in the same relative position in the new document if the documents have the same dimensions and resolution.

Option 2: Copying Guides Between Documents (If Dimensions Differ)

If the source and destination documents have different dimensions, pasting will place the guide at the same pixel coordinate, which may not be the desired relative position. In this case:

1. Determine the Guide's Position: In the source document, select the guide with the Move Tool (V). Note its X or Y coordinate in the Properties panel (Window > Properties).
2. Calculate Relative Position: Divide the guide's coordinate by the width (for vertical guides) or height (for horizontal guides) of the source document. This gives you the relative position (a decimal value between 0 and 1).
3. Calculate New Coordinate: In the destination document, multiply the relative position by the width (for vertical guides) or height (for horizontal guides) of the destination document. This gives you the corresponding coordinate.
4. Create the Guide Manually: Drag a new guide from the ruler and then, with the guide selected and the Move Tool active, enter the calculated X or Y coordinate in the Properties panel to precisely position the guide.

Option 3: Saving and Loading Guide Presets

For repetitive tasks, consider saving and loading guide presets:

1. Create your Guides: Arrange guides as desired in your source document.
2. Save Guide Preset: Go to View > New Guide Layout… Click "Save Preset..." and name it accordingly.
3. Load Guide Preset: In the destination document, go to View > New Guide Layout… and load your saved preset from the "Preset" dropdown.

Notes:

• Ensure "Snap" (View > Snap) is enabled for precise placement.
• Locking Guides (View > Lock Guides) prevents accidental movement.

In conclusion, while you can't directly copy grid lines, using and copying guides, or saving and loading guide presets, offers a flexible alternative for replicating layouts across multiple Photoshop documents.