Image Resolution

I recently read an article on iStockphoto about image resolution. Many people get confused when it comes to amount of pixels versus pixels per inches (ppi, also known as dots per inch or dpi). As a graphic design professional, I have known many professional designers who didn’t understand the difference. iStockphoto’s article gives a very good overview of the difference and explains how to calculate the total inches (or centimeters) of an image based on the ppi and total pixels.

Photoshop users have it easy. The Image Size dialog box automatically calculates the inches for you based on the resolution you need. The most important thing to remember when changing an image’s resolution from 72 ppi to a printable resolution is to uncheck the Resample Image checkbox at the bottom of the dialog box. If the box is checked, you will pixelate your image and it will be unusable.

The most important thing to remember about image size is the resolution is not important – the total pixels are. The resolution can be changed, but the total pixels need to stay the same to avoid pixelation. A 3000×4000 pixel 72 ppi image can be changed to 300 ppi, but the 3000×4000 pixels must NOT be changed. There are techniques to get around this in a pinch, but changing the amount of pixels should be avoided unless absolutely necessary.

To figure out the measurement of the picture in inches, you will need to divide the number of pixels by the resolution. A 3000×4000 pixel image at 72 ppi will be roughly 41.6″x55.5″. When the image is changed to 300 ppi, it will be 10″x13.3″.

And remember…not all images need to be printed at 300 ppi. It really depends on the project and the printer.


LearnKey Blog Guest Post: Woman Turns Alien via Photoshop

A little while ago, I had the opportunity to write a guest post for LearnKey’s blog, and my post went online today. The post is about a picture I made a while back in Photoshop of an alien while following a tutorial online. We’re going to be filming the Adobe CS5 Suite, starting with Photoshop next week, so I was asked to write a little something showing an interesting way to use Photoshop. Check out my post at blog.learnkey.com/?p=789.


Paint.NET

About a week ago, I discovered an image editing program called Paint.NET. It was originally a college project meant to create a program to replace Microsoft Paint, but has grown into a full-fledged photo editor, supposedly rivaling Photoshop and PaintShop Pro.

While I haven’t had much time to test this claim, I like what I have seen so far. For my first experience with the program, I attempted to cut out a picture of a buffalo using the Magic Wand tool, and I actually got a better result than I did doing the same thing with the same picture in Photoshop. One thing I like about Photoshop is all the filters, but Paint.NET has plug-ins which can be downloaded which may do the same things. I haven’t had a chance to look through them yet.

While I love Photoshop, Paint.NET definitely has one advantage: the cost. It’s pretty hard to beat Free.