How much can you enlarge JPEG's?

defektive

Veteran
May 4, 2011
43
Tasmania, Australia
Sam
I have an image that was shot in JPEG that I would like to enlarge. I have not enlarged anything since going digital so would like some comments on how far you can push a JPEG before things start getting ugly please.

Cheers,
Sam
 

Streetshooter

Administrator Emeritus
Jul 12, 2010
123
Philly, Pa
It depends more on the file size then the format of the file.
What file size do you have? What sensor/camera is the file from?
I am very comfortable with 11 x 14 paper with a 9 x 1/ image size. This gives me a standard uncropped image. It's my standard size. I've made 16 x 20 & a few 20 x 24's and I am very happy.
Most online printers prefer jpeg files. So I shoot raw, make a tiff in LR and convert to jpeg for printing.
Hope this is a start.
Don
 

bilzmale

Super Moderator Emeritus
Jul 17, 2010
124
Perth, Western Australia
Bill Shinnick
If you want to enlarge any image you are using interpolation which means the program 'makes up' the new pixels based on what is nearby. This leads to degradation of the image as you have alluded to.

Suppose you want to increase the size by 50% from say 4000x3000 pixels to 6000x4500 pixels. The number of pixels goes from 12 million to 27 million - that's a lot of new 'made up' pixels.

There is a strong belief that it is better to use no more than a 10% increase and to repeat the resizing in 10% bites till you get to the size you want.

There is software that will resize with minimal quality loss such as onOne's Perfect Resize (previously called something like Genuine Fractals). I have this software and you can probably download a trial.
 

defektive

Veteran
May 4, 2011
43
Tasmania, Australia
Sam
It depends more on the file size then the format of the file.
What file size do you have? What sensor/camera is the file from?
I am very comfortable with 11 x 14 paper with a 9 x 1/ image size. This gives me a standard uncropped image. It's my standard size. I've made 16 x 20 & a few 20 x 24's and I am very happy.
Most online printers prefer jpeg files. So I shoot raw, make a tiff in LR and convert to jpeg for printing.
Hope this is a start.
Don
Thanks Don. I generally shoot as you do, in RAW then convert to JPEG, but for some reason the camera was set to JPEG when I captured this one. Is there a difference in image quality when you enlarge one that has been shot in JPEG vs one that has been shot in RAW then converted to JPEG?

In answer to your questions:
1) File size is 6.30MB, 3615 long, 672 high, resolution 300
2) Camera used was an M8 set to ISO 640

If you want to enlarge any image you are using interpolation which means the program 'makes up' the new pixels based on what is nearby. This leads to degradation of the image as you have alluded to.

Suppose you want to increase the size by 50% from say 4000x3000 pixels to 6000x4500 pixels. The number of pixels goes from 12 million to 27 million - that's a lot of new 'made up' pixels.

There is a strong belief that it is better to use no more than a 10% increase and to repeat the resizing in 10% bites till you get to the size you want.

There is software that will resize with minimal quality loss such as onOne's Perfect Resize (previously called something like Genuine Fractals). I have this software and you can probably download a trial.
Thanks Bill. I am not sure how pixels equate to inches/centimeters but I would like to end up with an image around 36-40 inches on the long side.
When you talk about resizing in 10% increments does that require special software or can I do that in PSE 9?

Sam
 

Petach

Hall of Famer
Oct 22, 2011
123
UK, Essex
Peter Tachauer
If it helps: As a prolific enlarger.........(I print BIG) I have never seen a discernible loss of quality. I have printed jpeg files of 5mb at up to A1, framed and sold them.

If printing t home, what does make a difference is HOW you print the files. i.e. make sure your monitor/printer calibrated, use the right inks, use the right paper settings. I use a Canon ix6550 and my experience in printing (I can do A3+) is that I wasted a hell of a lot of ink and paper before I got it off to a T. All printer manufacturers have updated print profiles available for downloading.

Hope this helps.


Pete
 

Lawrence A.

Hall of Famer
Nov 8, 2012
124
New Mexico
Larry
I took a 3 mp file a number of years back, resampled and resharpened and had a 20x24 inch poster made of it that looked quite good. It was a humorous shot, and not gallery quality, but retained a suprising amount of detail.
 

ReD

Hall of Famer
Mar 27, 2013
123
Likewise I have had very acceptable 20x24 prints done off a 3Mp image camera
 

SnapDawg

Rorschach Test Pilot
Apr 18, 2014
103
Canary Islands
Ken
I did a number of A0 and A1 B&W prints from my X10 about two, three years ago. They look just fine, but it took some time in PS to polish the files.
 

ReD

Hall of Famer
Mar 27, 2013
123
A0 sounds good would love to give that a crack - it then depends on the distance viewed at
 

SnapDawg

Rorschach Test Pilot
Apr 18, 2014
103
Canary Islands
Ken
In case of the X10, those files are not exactly made to be printed at sizes beyond A3, if at all - even at base ISO. The 12MP (L mode) are nowhere near ideal 12MP, there are EXR specific artifacts, no proper RAW converters, a lot depends on the structures of your subject and so on. With 4000*3000 pickles on A0 you'd end up at about 85dpi or 3.5 dots/mm and I'd say 2 feet would be the minimum viewing distance but I spent some time experimenting with those files, used different masking, sharpening and upsizing techniques, did a number of small sample prints until I got what I wanted - huge jpgs and the prints. Anyway, I had lots of fun, a great print service and it's not that expensive.
 

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