Enlarging picture details without any visible losses(Photoshop CS, CS2, CS3, CS4)

               Today, a 12 megapixel resolution is almost standard; in spite of that, it can still be less, basically when you want to enlarge a small detail in the picture. Conventional enlargement techniques hamper the eff ect of the photo, which leads to loss in details in the photo.
               At the latest when the resolution falls below 100 dpi (Dots per Inch, pixels per inch) because of upscaling the picture contents, it has a negative effect in print. It is not only the blur edges then, which spoil the joy of a large format print. You can get optimum quality even for bigger prints with a resolution of approximately 300 dpi. Detail enlargements are basically possible hundred times more. The achievable result naturally depends on the subject and its sharpness largely. The reason being that soft and unfocussed area look rather unpleasant in the enlargements.

ELIMINATING IMAGE NOISE: Scaling not only enlarges the desired image contents but also interfering artefacts. It is better if you try and eliminate them beforehand. First remove the image noise since the filter does no longer recognizes this as such later. For that, click ‘Filter | Noise Filter | Reduce noise’ (from CS3 onwards, ‘Noise | Reduce noise’ previously) and adjust the effect of the filter on your subject. However, proceed cautiously otherwise you will end up eliminating too many details. After this treatment, the photo looks a bit soft at first. Never mind, it can be sharpened later.
SPECIFYING THE DETAIL: Now specify the desired picture detail. Activate the ‘Crop’ tool for that; the fastest way to do it is by pressing the key [C] and drawing a frame. Adjust its size more accurately using the controls. Double-clicking the selection releases the area. If you want to set accurate dimensions, enter them in the field in the options bar. Important here: release the ‘Resolution’ field, otherwise Photoshop will integrate the missing pixels.
UPSCALING THE PICTURE: Now call up the ‘Image Size’ function with [Alt]+[Ctrl]+[I]. Activate ‘Re-apply image with’ and select ‘Bicubic smooth’. Enter the desired value in ‘Resolution’, e.g. ‘300 dpi’, and change the height and width if necessary. Clicking ‘OK’ executes the command.
RE-SHARPENING THE EDGES: The enlarged pictures looks relatively soft at first, basically at the contrast edges such as letterings. You must re-sharpen them at any cost and it is best if you do it with the ‘Unsharp Mask’ function, which is below the ‘Filter | Sharpen’ menu. In case of large format prints, you can easily sharpen more strongly. You can carry out a quick Before-After comparison by just clicking the preview picture once.