How do I blow up a picture to be poster size without changing the way it looks?

I have a picture but, its too small and if i try and make it bigger myself it comes out all blurry. I have heard of online places that blow up pictures but, will they come out blurry???How do I blow up a picture to be poster size without changing the way it looks?
The problem you are having is resolution. The more pixels you have in your original, the bigger enlargements that you will be able to get. Simply put, it the source file does not have the details, you are not going to get it done with an enlargement.



Hope that helps.How do I blow up a picture to be poster size without changing the way it looks?
If this is any guide for you, Flickr does not recommend using any less than 3000 x 4500 for a 20 x 30 poster. That's 150 dpi/ppi. This would look a little blurry if you viewed it from a 18-20'; away as you would a normal photo, but it will look okay from 3-4 feet away.



You can try making the largest print that is still acceptable to you and then scan that to yield a 3000 x 4500 ppi image that could then be uploaded to Flickr (Shutterfly, etc) to get a poster print. You will not add any detail, but at least it would not be pixellated (';blocky';)
If it is coming out blurry now, it will come out blurry at larger sizes.



As a guide, if you want a high quality colour print, you generally need to be printing at around 300dpi. You can get away with less, but with some loss of quality. Some half tone publishing is done at around 150dpi, depending on the paper. Newspaper publishing is even less.



My 4MP camera (2288x1712 pixels) can be enlarged to about 8';x6'; at 300dpi, or 12';x9'; (around A4) at 200dpi.
Like Inthemoment said, a lot depends on the resolution that is set for the image, otherwise the photo will come back blurry. Also the type of file you saved the picture as, as well as how many times you have altered it, may affect whether or not the file can be blown up or not. If it is a standard JPEG document, the file becomes more compressed each time you open and re-save it, making the file much smaller. Hope this makes sense.
You have to enlarge the image the proper way.



1) bicubic enlarge - done with photoshop, you go to the resloution screen and increase the size of the image by 10%(make the value 110%), do this as many times as it takes to get the resolution you need for the lrge size print.



2) Use a third part tool like BlowUp from alien skin or similar.