With careful upscaling you can increase almost any image to the size you need.
We all have been there; sometimes a client gives us an image he wants to use for a printed material but the image is at 72 dpis for web and it is the only image he has, he can’t replace it.
Normally this is a disaster and you would need some antacids. But with a careful upscalling you can increase the size of the image and use it even for printed material.
When you make an image larger you have to contend with the problem of inventing extra information that isn’t present at the original.
Photoshop uses a method of interpolating pixels. The problem is that interpolating tends to produce results that are fuzzy and blurry. You can’t put data that wasn’t in the original.
There are several methods to correct this. The first one is using a Plugin. Alien Skins Blow up http://www.alienskin.com/blowup/ brings a lot of detail. The downside is the price $ 199
The second method can be used directly in Photoshop, doing increases by 105%.
Sample Image: this image is 300 x 200 pixels at 72 dpis.
Step 1. 105% Increases
a) Select image size: image > Image Size
b) Multiply the width for 105%. In this case the result is 315.
c) Select Resample image: Bicubic Smoother
Step 2 Repeat the process
Repeat this process several times until obtaining the desire size. You can create a simple Photoshop action to perform this task. I repeated the process several times until my image was 800-pixel width.
By repeating many small enlargements you retain much of the crispness.
Step 3 Surface Blur
Filter > Blur > Surface Blur. Set it to 7 radius and 7 threshold.
Step 4 Smart Sharpen
Filter > Sharpen > Smart Sharpen. Set the amount to 100% and play with the radius to obtain the desire result.
Here you can se a comparison of and image scaled directly to 800 pixels and the other with 105% increments.
800 pixels directly
105 % increases
In spite of the hard edges of the calculator we have a very good result. It works better in smooth surfaces as skin.