Building a grid in Photoshop

by Fred Showker
J.R., a Photoshop 911 reader from Oklahoma writes :

quoting I've been reading tutorials online for a grid, but none of them really work out the way I want
      can you help me do a grid that works out evenly to the image montage I've got? end quote

Building a grid in Photoshop

This is the kind of grid mosaic photo we will buildGenerally speaking, most of those tutorials are quick and basic, just to generate ad revenue, and never really take into account the intended purpose of the piece. When planning a photo montage to fit into a grid -- if you want the grid to come out accurately -- you've got to do a little math and planning before Photoshop.

1) What is the final size and intended use?
2) Are the images all to the same, proper resolution?

Once you've established those two questions about the project, you can proceed at good speed. For this demonstration, I'll use a 600 pixel "final" size. (Since my web column is 600 pixels!) Knowing that, I assertain how many blocks I want in the grid. So, let's say 8.
600 divided by 8 = 75.

With that math, we know that our grid size will be 75 pixels. So, lets set up the file.

STEP Mosaic Montage File: Start the new file: 600 pixels by 400 pixels
Set the resolution to what ever is required for the final project, also keeping in mind the resolution of your existing images.

STEP Grid File: Start a second file and set it to 75 x 75 pixels, by the resolution of the original file. This is going to be your grid "tile" size.

Setting the Marquee to a fixed size to set up grid lines

STEP Pattern File for Grid Separators: to save time and tedium, we'll work in the 75 pixel grid file, with our Marquee (M) tool set to a Fixed Aspect Ratio of 78 x 3 pixels, and draw our first grid separator across the bottom.

Photoshop fixed ratio draws a perfect 3-pixel border

STEP Then reverse the numbers to 3 and 78 to draw the right side grid separator. I added some slop with the 78 just to make sure I got the full 75 pixels.
From this file, we'll make our Pattern for the Mosaic file.

Edit to Define Pattern in this file for our grid patternSTEP Define the Pattern: Now, Select All (Cmd/Ctrl A) and then choose
Edit > Define Pattern and then
Name the pattern and click Okay

This will save the two border lines as a pattern, which will become our grid in the Mosaic file. Note that we saved the right and bottom, white lines on a transparent layer. This will remain transparent in the pattern once generated.

To apply the pattern Select Edit then Fill and Pattern STEP Apply the Pattern: Keep this file open, but now select your 600 pixel Mosaic file to bring it to the front and active. In this file,
STEP Create a new blank layer (Click the "New Layer" button at the bottom of your Layers Palette.) and then
STEP Select Edit > Fill to initiate the Fill dialog
STEP Contents > Use: > Pattern
STEP Then scroll down until you find the pattern you just created. Select that pattern and finally, click Okay.

Your 600 pixel file now has a white pattern on a transparent layer that works out perfectly to the width of the file.

Mosaic montage file with grid ready for the montage

The depth is secondary, we'll work within even tile openings, then trim the depth later. If you are required to have a set depth to the file, then you'll have to do the math thing for both dimensions until you arrive at even tile sizes in both directions. Let me warn you at this point -- if the aspect ratio of the file doesn't allow for even sized grid tiles, you'll be forced to have rectangular grid tiles. This may or may not be what you want.

Next: Build our montage mosaic in the grid file

... continues on the next page!

30th Anniversary for DTG Magazine