Guy writes: : I am interested in knowing the group's experience with blowing-up files for : printing to very-large format. I am working with a Sony A100 10 megapixel : DSLR and I am curious to find out how far I can blow-up a picture. have a look here Guy for a guide to algorithms relating to upward interpolation - really, REALLY worth a look! http://www.americaswonderlands.com/digital_photo_interpolation.htm and a point I've made before: different algorithms are better for different jobs, so it's well worth knowing which one is best for whatever you are doing.. a basic primer can be found here: http://www.interpolatethis.com/interp.html : What is the best program to use? not so much the program, as what the program offers in the way of upsizing algorithms (inherently or as a plugin). Photoshop's default is bicubic (eww!) it also has bilinear. That's all it offers.. and beating a far from dead horse again - Irfanview has the inbuilt algorithms : Bell B-Spline Hermite Lanczos Mitchell Triangle (and Irfanview is both free and tiny! :) : How far can I go on enlarging the file? that very much depends on the image ;) S spline is rather nice too I might add.. However if it's for a print then I'd recommend examining the output of various RIP's from whatever each printer offers, often they'll do a FAR better job than any of the RIP's available to us photographers. Using a RIP is less demanding time wise on the computer too, and prevents the printer falling in a heap when it gets a terabyte image sent to it (!) The best way to do this is to select a small portion of the image and have enlarged X times to make say an 8x10.. have them print this and look at the results with a critical eye. hope this helps.. karl
