Gradual increase
10% at a time
Used a good
commercial software
Gradual Interpolation vs Commercial Software
You can get excellent results when upsampling by increasing the image size in several small increments rather than one extreme step. One advantage to using this technique is that it will work on 16-bit mode images and it requires no additional software other than a standard photo editor.
This technique is simple: rather than using the image size command to go directly from 100% to 400%, you would use only increase the size by 10% at a time. Then you would repeat the command as many times as it takes to get to the size you want.
Is it really possible to resample an image manually as described above maintaining reasonable quality?
Will a leading software programme dedicated to resampling, achieve better results?
We have made a test and you can judge the result.
Both images were treated the same.
I selected a RAW photo and did the usual adjustments in LightRoom 3, then saved it as a 16-bit image, (Fig 1).
This became the source image and nothing else was done it.
First, I cropped the Kestrel and upsampled it manually as described above until it reached the size, 1800 X 2400 pixels., document size, 6 X 8 inches).
Second, I used the commercial software. The operation is done automatically and quickly. Selected the best quality option - the conversion process took about 5 minutes to complete.
Then from each picture I enlarged the right eye by 200%.
CONCLUSIONS
Both methods produced excellent results considering the size of the enlargement.
The left eye is softer and has less contrast than the right eye.
The commercial package gave better results - but is the difference that great? Unless you need to resample your pictures often you may find that the manual method is good enough.
