## Introduction: 3D Lenticular Printing Using Photoshop and Inkjet Printer

3D lenticular print is a way to present 3D effect on a flat surface.  The idea is to use a plastic sheet with many lined lenses so that light will be refracted in different angle for our left and right eyes.  When an image behind the lenticular sheet is designed in such a way that one image will be seen by the left eye and another image will be seen by the right eye a 3D effect will be rendered by our brain.

Lenticular sheet can be purchase online from microlens.com at about \$5.00 per piece.  In this tutorial we assume you will use the 8" x 10" 40 LPI lenticular sheet.  We further assume that only two pictures will be taken.  If you use LPI other than 40 and if you want to take more pictures to make the final image less sensitive to horizontal head movement then please refer to the original tutorial in the 3D Lenticular Printing Tutorial section of vicgi.com

## Step 1: Take Two Pictures With Binocular Disparity

Find an object of interested about 2m from the camera, then take two pictures along a straight line with the displacement between the left and right about 60mm.

Refer to the instructable on how to make a track for the camera to move horizontally, https://www.instructables.com/id/Stereo-Photography-Track-quick-and-dirty .

You can also purchase the slider bar for about \$100 from http://www.stereoscopy.com/jasper/slide-bars.html.

Alternatively, just tie the camera on a die-cast model car and move it along a straight line.

If you just want to do it as an exercise, you can download the two high resolution pictures in this step.

## Step 2: Find the Key Plane of Lenticular Picture

Once the pictures are taken, conceptually divide the picture into three planes, i.e. the foreground, the middle-ground, and the background.

Now make the decision which will be the focal plane.  A focal plane is the plane that does not have parallax.  In other word the left and right eyes will be seeing the same image on the focal plane.

If you choose the foreground as the key plane, everything behind the foreground will go into inside of the lenticular picture.  If you choose the middle-ground as focal plane, the foreground will pop out of the picture and the background will go into the picture.  If you choose the background as the focal plane, the middle-ground and the foreground will pop out of the picture with the foreground being closer to your eyes.

## Step 3: Align a Common Point on the Key Plane

Now find a point on the focal plane.  The purpose is to align this point so that the x-y coordinate of this point will be the same on both the left and the right picture. For the two pictures in step-1 as example, we can choose the pot as the foreground and as the focal plane, or we can choose the table and chair at the middle-ground as the focal plane.  For the sake of exercise let's choose the latter, i.e. the table and chair as the focal plane.

Open both picture in Photoshop.  Copy and paste the right picture on top of the left picture.  Adjust the [Opacity] of the right picture to about 50% so you can see through it and the left picture below it.

Now choose the [Move] tool from the tool bar and then press the [Right] arrow on the keyboard multiple times so that the most forefront table legs overlap.

You can adjust the [Opacity] of the right image back to 100% now.

## Step 4: Crop the Image to Account for the Shift During Alignment

Because of the alignment in the previous step, the right picture has shifted to the right leaving some empty space on the left.  Use the crop tool from the tool box to crop the image to eliminate the empty space.

## Step 5: Resize the Image

Resize the [Resolution] of the image to 720 dpi if you are going to use an Epson printer.  Resize it to 600 dpi if you are going to use an HP or a Canon printer.

Once the resolution is adjusted, resize the width or height so they will match the size of the lenticular sheet you have.

## Step 6: Create a Mask for the Left and Right Image

Create a new file of the same size as the picture.  Draw some vertical bars 9 pixel wide and 9 pixels apart.  For the left picture you will need the mask start with white stripe and then black stripe.  But for the right picture you will need the mask start with black stripe and then white stripe. Flatten this image.  Press [Ctrl-A] to select all and the [Ctrl-C] to copy and put the pattern into the clipboard.  We will need to paste it over the mask of the left and right image in the next step.

## Step 7: Interlace Each Image With the Mask Created

Go back to the original file with the left and right image.

Create a mask for each of the layers by clicking the little [Mask] button on the [Layer] palette, i.e. the third one from the left.

Bring up the [Channel] palette and  highlight the mask layer under [Channel].  Paste the left patten we did in the previous step over to the mask layer.

Highlight the right layer on the [Layer] palette.  Repeat the same for the right layer, i.e. paste the pattern for the right layer, the one starts with black stripe, to the mask layer under [Channel].

## Step 8:

Flatten the final image.  Print it on photo glossy paper.  Put your lenticular lens on top to do some careful alignment.

If your lenticular sheet has adhesive backing then you will need to use a cold laminator to do the lamination.  If it doesn't have adhesive backing then try to tape it in position.

Voila! Your 3D DIY lenticular print is done.

As you can see making a single sheet of lenticular print is very tedious.  If you need volume mass production you should consider hire a lenticular printing company to do it.