Printing help: how to get 18x24" size photo on 20x30 Costco print

DriedStrawbery · Jan 15, 2017

Costco has cheap 20x30 prints.
Michael's has cheap 18x24 frames.

I want to crop my pics in 3x4 aspect ratio and want to order a 20x30 size print in Costco. The space outside the 18x24" can be white.

How can I prepare an image (maybe by adding extra white border outside the pic?) so that the final 20x30" print at Costco can be cut and I get my pic that leave me with 18x24 print?

Alternatives are: I buy 20x30" frame. Or order 18x24" prints

. But these are relatively expensive.

Any suggestions?

Thanks.

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480sparky · Jan 16, 2017

What is the size, in pixels, of the image you want to print? From that, you can calculate mathematically, how big (in pixels) your white canvas should be. Create the white canvas that big, copy and paste your image to it, and center it on the white canvas.

Send it off to Costco, making sure they understand you know you're getting a large white border. Otherwise, you just might end up with a full 20x30 print.

KmH · Jan 16, 2017

I take it you don't want a mat in front of the print?

A mat in front of a print serves 2 purposes - 1 artistic and the other physical.
The physical purpose is keeping the print away from the glazing (glass/acrylic).
The artistic purpose is to visually separate the image from the wall where it hangs.

However, when I wanted a custom size print I did just as Ken (480sparky) has suggested, but added thin lines to indicate where I wanted the lab to trim off some of the excess blank white border so the print would fit in a frame of the size I intended to use.
If I wanted no excess white border I simple added text in the blank white space saying "Please trim to image edges."

Most labs don't charge extra to trim for you, though they usually have a size limit such that you have to order a print larger than their limit.

adamhiram · Jan 16, 2017

Here is how I would do this using Photoshop, no math needed...

Image > Image Size

Uncheck "Resample"
Width = 16 inches
Height = 24 inches (should default to this after setting width)

This will adjust the DPI setting without affecting the image quality. Now Photoshop knows your image is 16x24.

Image > Canvas Size

Width = 20 inches
Height = 30 inches
Anchor = Center (default)
Canvas extension color = white

This will extend the canvas to the full print size that the printer needs. The actual image printed will be 16x24 with a white border.

DriedStrawbery · Jan 16, 2017

Thanks! Are there any other software that can do this? Seems like a simple function in image processing.

I was confused about how to get print measurement from pixel length... as we have a high res pic printed into one of many sizes...

480sparky · Jan 16, 2017

Most editing software can do it. It may not be the same steps as PS.

To get print measurements from pixel sizes, it's must a matter of calculating the multiplier. Your desired print will be 24", and your Costco print will dress out to 30 inches. 30/24= 1.25. Meaning, your canvas size will need to be the long pixel dimension of the image x 1.25.

Also, if you can work with inches instead of pixels with your software, set it up that way and you're golden.

KmH · Jan 16, 2017

adamhiram said:
This will adjust the DPI setting without affecting the image quality.

It adjusts the PPI setting.
If you look at the Image Size dialog box we can see that Adobe uses the correct terminology.

DPI and PPI are not interchangeable terms because they refer to different things.

While no math may be needed with that method, understanding the math is very, very, very beneficial most of the time.

Garasaki · Jan 31, 2017

adamhiram said:
Here is how I would do this using Photoshop, no math needed...

Image > Canvas Size

Width = 20 inches

Height = 30 inches

Anchor = Center (default)

Canvas extension color = white

This will extend the canvas to the full print size that the printer needs. The actual image printed will be 16x24 with a white border.