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Photoshop Corner #008

"Intelligent Upsampling: Stair Interpolation (SI)"

by Fred Miranda

 

Everyone involved with digital imaging has heard about Genuine Fractals. This utility claimed to do a better job interpolating digital images than Photoshop's bicubic engine. Now I would like to introduce a new utility. It's called SI.

In my opinion, Photoshop's Bicubic interpolation, when done in several small steps (like SI is designed), yields better results than the expensive Genuine Fractals plugin. In addition, it works in 16-bit mode!

I have many examples which prove this point. Using the Stair Interpolation (SI) action, your interpolated images look sharper and make beautiful 8x10, 13x19, or even 20x30 prints. The secret of SI is that it interpolates images in small steps rather than one large step. The results are remarkable. After running the action, the SI images are clearly superior to Genuine Fractal's and much better than if you had used Photoshop Bicubic alone.

The samples are 100% crops from the image below:

 
 

Genuine Fractal was used with its best interpolation method and encoding.

Compatible with Photoshop 5.0, 5.5, 6.0 or higher (PC and MAC)

 
1.5x Full Size
 
Genuine Fractals v2.0
Stair Interpolation (SI)
 
Photoshop Bicubic
 
2x Full Size
 
Genuine Fractals v2.0
Stair Interpolation (SI)
 
Photoshop Bicubic
 
3x Full Size
 
Genuine Fractals v2.0
Stair Interpolation (SI)
 
Photoshop Bicubic
 

As you can see from the above examples, the SI action is clearly a winner when it comes to interpolation of digital images before printing. Keep in mind, that much like Genuine Fractals, this action works better with faster systems. If you have an old system and not much RAM, this action may run slow, but it's well worth the extra time. I hope you enjoy it!

The 1.5X, 2.0X, 3.0X, and 4.0X options refer to the amount of up-sampling (interpolation) relative to your image size. My intention was to make this action compatible with any digital camera. Therefore, I chose these commonly used increments.

My advice is to choose between the given choices that closely match your output print size and then use Photoshop's "image size" to fine-tune it.

 
 
Fred Miranda
 
 
 
 

 

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