You cannot put in detail that is not there. It is empty magnifications you get it in optics also. If you want detail do not use jpeg. Other forms of compression are available like TIff and Gem. These are lossless. You need a big aperture lens also and a large format camera... Like the old days and of course a big optical sensor with a huge number of pixels. Dr Chris. Christopher Strevens -----Original Message----- From: owner-photoforum@xxxxxxxxxxxxxxxxxx [mailto:owner-photoforum@xxxxxxxxxxxxxxxxxx] On Behalf Of Eichhorn, Roger Sent: 23 August 2014 23:55 To: List for Photo/Imaging Educators - Professionals - Students Subject: Re: Large print - quality issue Scott Kelby, in one of his early photoshop books, suggested that one could blow up photos by a few percentage points at a time. I tried it with a jpeg file and it worked. For example, increasing the size by 5 percent fifteen times will approximately double the size of the image (2.08.) I don't l know if it will work for you, but it might be worth trying. You can solve the equation (1.0x)^n = y, for n, where x is the percentage increase for each iteration, y is the final size and n is the number of iterations. Roger Sent from my iPad > On Aug 22, 2014, at 8:05 PM, "James Schenken" <jds@xxxxxxxxxxxxxxx> wrote: > > Oops, I calculated at 3000 pixels on the long dimension rather than 4000. > Please make adjustments accordingly. > Sorry about that. > > CPAP Therapy is a way to live. > >> On Aug 22, 2014, at 8:44 PM, James Schenken <jds@xxxxxxxxxxxxxxx> wrote: >> >> The problem appears to be that the image magnification is about 44 times. >> The image resolution is about 83 pixels per millimeter. >> So, what you get if everything is perfect is 2 pixels per millimeter or about 50 dpi. >> That's OK if everyone is going to be 15 feet away from the image or so. >> >> Any chance the museum would go for a black and white half tone for a background? >> >> CPAP Therapy is a way to live. >> >
