how to interpolate/scale up digital photos?

[betoinorge]

Hi ! I wonder if anyone could tell me how to interpolate a file (jpeg or Tiff) using Adobe Photoshop 7 ? I am gonna send some photos to a Photo Stock Agency and they asked me to interpolate my photo files so that they can be between 18 and 25 MB. I use a Canon powershot S45 that gives me files of 10MB.

 

[Kliot]

From File - Image Size select "Resample Image" and you have 3 options for interpolation (Bicubic, Nearest Neighbor & Bilinear)

 

[Eggles]

Bear in mind that PS is guessing what colour those extra pixels should be by sampling the neighbouring pixels. Sometimes it does a good job and other times it looks terrible, depending on the subject/colour. It is best if you do the upsampling in small increments rather than one big jump as the results are usually a little better.

Have a read of Fred Miranda's site

http://www.fredmiranda.com/SI_PRO/

 

[blueark]

If you are starting from a 10mb file, using the bicubic setting in Image Size will more than likely give you acceptable results.

Also, when you are dealing with file sizes, keep in mind that it refers to the uncompressed image (as shown at the bottom of the Photoshop window) rather than the file size itself (which may be compressed to save space). This is especially important for JPEGs.

 

[fotog]

Interpolation/resizing info can be found in great detail at (you guessed the URL!):

http://www.interpolatethis.com

particularly the forums section.